RASAL1: A Calcium-Regulated RasGAP with Dual Specificity and Tumor Suppressor Function

Introduction

RASAL1 (RAS Protein Activator Like 1, UniProt O95294) is a member of the GAP1 subfamily of GTPase-activating proteins (GAPs) that functions as a negative regulator of Ras signaling. Originally cloned from human frontal cortex cDNA by Allen and colleagues in 1998, RASAL1 encodes an 804-amino acid protein with a distinctive modular architecture consisting of two N-terminal C2 domains, a central catalytic RasGAP domain, and a C-terminal pleckstrin homology (PH) domain [allen-1998-rasal-cloning-abstract]. The protein exhibits a remarkably restricted tissue expression pattern compared to other RasGAPs, being highly expressed in thyroid follicular cells, adrenal medulla, and at lower levels in the brain [allen-1998-rasal-cloning-abstract]. This tissue specificity distinguishes RASAL1 from other GAP1 family members, which show more widespread expression patterns.

RASAL1 functions as a tumor suppressor by enhancing the intrinsic GTPase activity of wild-type Ras proteins, thereby converting Ras from its active GTP-bound state to its inactive GDP-bound state. This regulation is essential for controlling cellular proliferation and differentiation downstream of receptor tyrosine kinase signaling. Importantly, RASAL1 exhibits dual specificity, capable of inactivating both Ras and the related GTPase Rap, although the mechanisms and regulation of these two activities differ substantially [sot-2013-rasal-membrane-abstract]. Loss of RASAL1 function through epigenetic silencing or mutation has been implicated in multiple cancer types and in fibrotic diseases, establishing it as an important regulator of cellular homeostasis.

Domain Architecture and Structure

RASAL1 possesses a characteristic domain organization shared with other members of the GAP1 subfamily, which includes GAP1m/RASA2, GAPIP4BP/RASA3, and CAPRI/RASA4 [simanshu-2019-rasgap-review-abstract]. The approximately 95 kDa protein contains four distinct functional domains arranged in the order C2A-C2B-GAP-PH from N-terminus to C-terminus.

The two tandem C2 domains at the N-terminus share structural similarity with the calcium-dependent phospholipid-binding domains found in synaptotagmin and protein kinase C [allen-1998-rasal-cloning-abstract]. These domains are critical for RASAL1's calcium-regulated membrane translocation and possess distinct lipid-binding specificities. Detailed biochemical analysis by Sot and colleagues demonstrated that the C2A domain binds specifically to phosphatidylserine (PS), while the C2B domain interacts with several phosphoinositide lipids [sot-2013-rasal-membrane-abstract]. This dual lipid recognition enables precise membrane targeting in response to calcium signals.

The central GAP-related domain (GRD) contains the catalytic machinery necessary for stimulating GTP hydrolysis on Ras family members. This domain contributes the critical arginine finger that is essential for RasGAP catalysis [sondermann-2010-dual-gap-mechanism-abstract]. The C-terminal PH domain provides additional membrane-targeting capability and has been shown to interact with calcium-sensing proteins including CaMKII-α and protein kinase C [deurloo-2024-rasal1-neuronal-abstract].

Electron microscopy studies have begun to reveal the relative organization of these individual domains, though high-resolution structural information remains limited [simanshu-2019-rasgap-review-abstract]. The interdomain interactions appear to be critical for regulating RASAL1's catalytic activity, as the protein exists in an autoinhibited state in solution that is relieved upon membrane binding.

Molecular Function and Catalytic Mechanism

The primary molecular function of RASAL1 is to accelerate the hydrolysis of GTP bound to Ras family GTPases, converting them from the active signaling state to the inactive GDP-bound form. A remarkable and distinguishing feature of RASAL1 is its dual specificity for both Ras and Rap GTPases, combined with the unusual property that isolated soluble RASAL1 protein exhibits RapGAP activity but lacks RasGAP activity [sot-2013-rasal-membrane-abstract].

The activation of RASAL1's RasGAP function requires both colocalization with membrane-bound Ras and calcium-dependent binding of the C2 domains to membrane phospholipids [sot-2013-rasal-membrane-abstract]. This spatial and conformational regulation ensures that RASAL1 only inactivates Ras when both proteins are appropriately positioned at the plasma membrane. In contrast, the RapGAP activity of RASAL1 does not require membrane association and can be observed with the soluble protein in vitro. The molecular basis for this regulatory switch involves conformational changes in the GAP domain that are triggered by C2 domain-lipid interactions, though the precise structural mechanism remains to be elucidated.

The catalytic mechanism for GTP hydrolysis on Ras involves the conserved "arginine finger" mechanism characteristic of RasGAPs. The GAP provides an arginine residue that inserts into the active site and helps orient the catalytic glutamine (Gln61) of Ras, which in turn positions a water molecule for nucleophilic attack on the gamma-phosphate of GTP [sondermann-2010-dual-gap-mechanism-abstract]. For Rap substrates, which lack the equivalent of Gln61 (possessing instead a non-catalytic threonine at that position), the mechanism differs. Dual-specificity GAPs like RASAL1 use their extra-GAP domains (C2 and PH) to promote a different orientation of Rap's switch-II region, allowing Rap Gln63 to serve as the catalytic residue [sondermann-2010-dual-gap-mechanism-abstract]. Deletion of the C2 domains dramatically reduces RapGAP activity by more than 1000-fold while having minimal impact on RasGAP activity, demonstrating the essential role of these domains in dual specificity.

Calcium-Dependent Regulation and Membrane Translocation

A defining characteristic of RASAL1 is its regulation by intracellular calcium oscillations. The C2 domains function as calcium sensors that enable RASAL1 to shuttle dynamically between the cytoplasm and the plasma membrane in response to changes in intracellular calcium concentration [simanshu-2019-rasgap-review-abstract]. This behavior differs from the related protein CAPRI, which associates stably with membranes upon calcium elevation; RASAL1 instead senses calcium oscillations and continuously shuttles between compartments.

Live cell imaging studies have demonstrated that elevation of intracellular calcium induces rapid plasma membrane association of RASAL1. In neurons, perfusion with depolarizing solution induced plasma membrane translocation that began within 2 seconds and was complete within 8 seconds [deurloo-2024-rasal1-neuronal-abstract]. This translocation is reversible, with RASAL1 returning to the cytoplasm as calcium levels decline. The calcium dependence is mediated entirely through the C2 domains rather than through direct effects on the catalytic domain; addition of calcium in the absence of membranes has no effect on RasGAP activity, confirming that membrane colocalization is the critical activating event [sot-2013-rasal-membrane-abstract].

The functional consequence of this calcium regulation is that RASAL1 acts as a decoder of calcium signaling, translating patterns of calcium oscillations into modulation of Ras activity [jin-2007-rasal-methylation-abstract]. This provides a mechanism for integrating calcium-dependent signaling pathways with the Ras-MAPK cascade, allowing cells to coordinate diverse extracellular signals that elevate intracellular calcium with growth factor signaling through receptor tyrosine kinases.

Subcellular Localization

Under basal conditions with low intracellular calcium, RASAL1 exhibits a diffuse cytoplasmic distribution throughout the cell body. In neurons, this includes expression in soma, dendrites, and axons [deurloo-2024-rasal1-neuronal-abstract]. Upon calcium elevation, RASAL1 rapidly translocates to the plasma membrane where it colocalizes with its Ras substrates. This membrane localization is essential for its RasGAP function, as the colocalization of RASAL1 and Ras at the membrane is required for catalytic activity.

The PH domain at the C-terminus may provide additional membrane-targeting capability through interactions with phosphoinositides, potentially stabilizing membrane association or directing RASAL1 to specific membrane microdomains. However, the C2 domains appear to be the primary determinants of calcium-regulated localization.

Signaling Pathways and Downstream Effects

RASAL1 functions as a negative regulator of the Ras signaling cascade, and its activity impacts two major downstream pathways: the MAPK pathway (RAF→MEK→ERK) and the PI3K pathway (PI3K→AKT→mTOR). Functional studies in thyroid cancer cells demonstrated that wild-type RASAL1 expression reduces levels of both phosphorylated ERK and phosphorylated AKT, indicating suppression of both pathways [liu-2013-rasal1-thyroid-abstract]. Cancer-associated mutations in RASAL1 that impair RasGAP function lost the ability to suppress these pathways, confirming that the tumor suppressor activity of RASAL1 is mediated through Ras inactivation.

Beyond classical Ras signaling, RASAL1 has been shown to have additional signaling functions in specific cellular contexts. In T lymphocytes, RASAL1 associates with the tyrosine kinase ZAP-70, a critical component of T-cell receptor (TCR) signaling [thaker-2019-rasal1-zap70-abstract]. This interaction involves binding of RASAL1 to the kinase domain of ZAP-70, resulting in inhibition of ZAP-70 kinase activity. Thus, RASAL1 inhibits T-cell activation through two parallel mechanisms: direct inhibition of ZAP-70 and GAP-mediated inhibition of the p21ras-ERK pathway downstream of the TCR.

In neurons, RASAL1 participates in a calcium-decoding complex that includes CaMKII-α and protein kinase C (PKC), both of which are calcium-sensing proteins [deurloo-2024-rasal1-neuronal-abstract]. Additionally, RASAL1 interacts with α- and β-tubulin, suggesting roles in regulating the cytoskeleton. Functional studies showed that RASAL1 promotes tubulin detyrosination, a post-translational modification that stabilizes microtubules. This activity inhibits dendritic outgrowth while promoting synapse formation and NMDA receptor-mediated synaptic transmission, illustrating how RASAL1 coordinates multiple aspects of neuronal maturation [deurloo-2024-rasal1-neuronal-abstract].

Tissue Expression and Physiological Roles

RASAL1 exhibits a remarkably restricted tissue expression pattern. The highest expression levels are found in thyroid follicular cells and the adrenal medulla, with lower expression in brain, spinal cord, and trachea [allen-1998-rasal-cloning-abstract]. This endocrine-enriched expression pattern distinguishes RASAL1 from other GAP1 family members and suggests specialized physiological functions in these tissues.

In the thyroid, RASAL1 appears to be a critical regulator of cell proliferation. The Ras-cyclic AMP pathway is particularly important in thyroid physiology, and RASAL1 acts as an inhibitory regulator of this pathway [allen-1998-rasal-cloning-abstract]. Loss of RASAL1 function through methylation or mutation is strongly associated with thyroid cancer development, consistent with its role as a major tumor suppressor in this tissue [liu-2013-rasal1-thyroid-abstract].

In the nervous system, despite high expression levels in brain, the physiological functions of RASAL1 have only recently begun to be characterized. RASAL1 appears to regulate calcium-dependent neuronal maturation, balancing neurite outgrowth against synapse formation [deurloo-2024-rasal1-neuronal-abstract]. This suggests roles in neural development and potentially in synaptic plasticity.

Role in Cancer

RASAL1 has been established as an important tumor suppressor, with its inactivation contributing to cancer development through loss of Ras pathway regulation. The mechanisms of RASAL1 inactivation in cancer include both epigenetic silencing through promoter hypermethylation and genetic inactivation through missense or nonsense mutations.

Epigenetic silencing of RASAL1 was first systematically characterized by Jin and colleagues, who demonstrated that RASAL1 is silenced through CpG methylation in multiple tumor types including hepatocellular carcinoma, esophageal carcinoma, breast carcinoma, nasopharyngeal carcinoma, and lymphoma [jin-2007-rasal-methylation-abstract]. Importantly, RASAL1 methylation was observed in tumor tissues but not in corresponding normal tissues, and treatment with the demethylating agent 5-aza-2'-deoxycytidine restored RASAL1 expression. Ectopic expression of RASAL1 in cancer cells inhibited tumor cell growth, confirming its tumor suppressor function.

In thyroid cancer, Liu and colleagues performed a comprehensive analysis that established RASAL1 as a major tumor suppressor [liu-2013-rasal1-thyroid-abstract]. Among 13 negative modulators of the RAS pathway screened, RASAL1 was most frequently hypermethylated. Additionally, RASAL1 mutations were found in 8 of 101 thyroid tumors examined, including one nonsense mutation (W594X) and seven missense mutations, all located within the RasGAP domain. The mutation frequency was highest in anaplastic thyroid cancer (16.67%) and follicular thyroid cancer (4.88%). Functional studies showed that cancer-associated mutations impaired RASAL1's ability to suppress MAPK and PI3K signaling and to inhibit tumor growth in xenograft models. Notably, RASAL1 inactivation was found primarily in tumors lacking classical RAS pathway mutations, suggesting it represents an alternative genetic mechanism for Ras pathway activation.

In colorectal cancer, decreased RASAL1 expression was associated with tumor progression [ohta-2009-rasal1-colorectal-abstract]. RASAL1 expression was reduced in most colorectal cancers with wild-type KRAS but rarely in those with mutant KRAS, demonstrating mutual exclusivity consistent with their shared pathway. RASAL1 was detected in approximately 47% of adenocarcinomas but absent in small adenomas, suggesting its loss occurs during the progression from benign to malignant lesions.

In gastric cancer, RASAL1 promoter hypermethylation is particularly frequent, occurring in 70% of gastric cancer tissues compared to 30% in paired adjacent non-cancerous tissues [chen-2013-rasal1-gastric-methylation-abstract]. Significant correlations were found between RASAL1 promoter methylation and clinicopathological features including tumor differentiation, tumor size, invasive depth, and lymph node metastasis. RASAL1 expression was found to be lowest in poorly differentiated gastric cancer cell lines, consistent with a tumor suppressor role [chen-2014-rasal1-gastric-abstract]. Functional studies demonstrated that RASAL1 knockdown increased RAS-GTP and phosphorylated ERK1/2 levels, promoting gastric cancer cell proliferation, invasion, and migration while reducing apoptosis. Conversely, RASAL1 overexpression inhibited these cancer cell behaviors. Treatment with the demethylating agent 5-Aza-CdR restored RASAL1 protein expression and decreased RAS/ERK pathway activation, confirming that epigenetic mechanisms regulate RASAL1 expression in gastric cancer [chen-2013-rasal1-gastric-methylation-abstract].

Role in Fibrosis

Beyond cancer, RASAL1 hypermethylation has been implicated in fibrotic diseases, particularly kidney fibrosis. Bechtel and colleagues demonstrated that RASAL1 hypermethylation is associated with the perpetuation of fibroblast activation and fibrogenesis in the kidney [bechtel-2010-rasal1-kidney-fibrosis-abstract]. The profibrotic cytokine TGF-β1 induces RASAL1 silencing through a mechanism involving the DNA methyltransferase Dnmt1. Treatment with TGF-β1 caused decreased Rasal1 mRNA expression within 8 hours, and Dnmt1 knockdown prevented this hypermethylation.

The epigenetic silencing of RASAL1 provides a mechanism for the perpetuation of fibroblast activation. Once methylated, the RASAL1 promoter remains silenced even after the initial fibrogenic stimulus is removed, and this methylation pattern can be inherited by daughter cells. This explains how transient exposure to profibrotic signals can lead to persistent myofibroblast activation. Importantly, kidney fibrosis was ameliorated in Dnmt1+/- heterozygous mice, and RASAL1 hypermethylation could be reversed by treatment with BMP-7, an endogenous TGF-β antagonist [bechtel-2010-rasal1-kidney-fibrosis-abstract]. These findings identify RASAL1 epigenetic regulation as a potential therapeutic target in fibrotic disease.

RASAL1 also plays an important role in liver fibrosis through regulation of hepatic stellate cell (HSC) activation. HSCs are the primary cell type responsible for liver fibrosis, and RASAL1 expression levels are inversely correlated with HSC activation [qiu-2017-rasal1-liver-fibrosis-abstract]. RASAL1 suppresses HSC activity through two distinct pathways: the Ras-MAPK pathway, which inhibits cell proliferation by reducing Ras-GTP activity, and an AGTR1-PKA-AMPK-SRF pathway involving interaction with angiotensin II receptor type 1 that suppresses fibrogenic gene expression including alpha-smooth muscle actin and collagen genes. Studies using RASAL1-deficient mice demonstrated enhanced susceptibility to liver fibrosis following chemical induction with carbon tetrachloride or thioacetamide, despite comparable levels of liver damage [qiu-2017-rasal1-liver-fibrosis-abstract]. These mice showed significantly greater fibrotic scarring than wild-type littermates, although no spontaneous pathological tumors were observed up to 48 weeks of age under normal conditions.

In cardiac fibrosis, RASAL1 methylation has been identified as a key driver of endothelial-to-mesenchymal transition (EndMT), a process contributing to the progression of heart fibrosis [xu-2015-rasal1-cardiac-fibrosis-abstract]. Long-term exposure to TGF-β1 induces aberrant CpG island promoter methylation of RASAL1 in coronary endothelial cells, leading to transcriptional silencing. This silencing increases intrinsic Ras-GTP activity and promotes EndMT. In non-failing human myocardium, increased fibrosis was associated with significantly increased RASAL1 promoter methylation, decreased RASAL1 expression, increased Ras-GTP activity, and increased expression of EndMT markers [xu-2015-rasal1-cardiac-fibrosis-abstract]. Importantly, BMP-7 treatment significantly reduced RASAL1 promoter methylation in mouse models of pressure overload-induced cardiac fibrosis, through a mechanism involving restoration of the demethylating enzyme TET3, which was found to be decreased in fibrotic hearts. This study established that epigenetic balance between methylation and hydroxymethylation at the RASAL1 promoter is a critical determinant of cardiac fibrosis progression.

Role in T-Cell Regulation and Tumor Immunity

RASAL1 has been identified as a negative regulator of T-cell activation and anti-tumor immunity through its interaction with ZAP-70 [thaker-2019-rasal1-zap70-abstract]. RASAL1 is expressed in activated CD4+ and CD8+ T-cells, where it associates with the kinase domain of ZAP-70, a critical mediator of TCR signaling. This interaction inhibits ZAP-70 kinase activity, providing a mechanism distinct from RASAL1's RasGAP function.

Functional studies demonstrated that RASAL1 inhibits CD4+ T-cell responses to antigenic peptides both in vitro (when presented by dendritic cells) and in vivo. From a therapeutic perspective, siRNA-mediated reduction of RASAL1 expression in T-cells enhanced anti-tumor immunity, resulting in shrinkage of B16 melanoma and EL-4 lymphoma tumors in mouse models [thaker-2019-rasal1-zap70-abstract]. This tumor shrinkage was accompanied by increased infiltration of CD8+ T-cells expressing the effector molecules granzyme B and interferon-γ. These findings identify RASAL1 as a potential immune checkpoint that could be targeted to enhance anti-tumor T-cell responses.

Open Questions

Several important questions about RASAL1 biology remain to be addressed:

1. Structural basis for dual specificity and membrane regulation: While biochemical studies have established that RASAL1 requires membrane binding for RasGAP but not RapGAP activity, the structural mechanism by which membrane association activates RasGAP function remains unclear. High-resolution structural studies of membrane-bound RASAL1 would provide important insights.

2. Physiological significance of dual Ras/Rap specificity: It is not known whether the RapGAP activity of RASAL1 is physiologically important or represents a vestigial function. Studies examining Rap-dependent processes in RASAL1-deficient cells could address this question.

3. Roles in specific tissues: The restricted expression pattern of RASAL1, particularly its high expression in thyroid and adrenal tissue, suggests tissue-specific functions that are not fully understood. The consequences of RASAL1 loss in adrenal physiology have not been characterized.

4. Contribution to neural function: While recent work has begun to characterize RASAL1 in neuronal development, its roles in adult brain function, synaptic plasticity, and neurological disease remain unexplored.

5. Therapeutic targeting: Given the tumor suppressor function of RASAL1 and its epigenetic silencing in cancer, strategies to reactivate RASAL1 expression (such as DNMT inhibitors or targeted demethylation approaches) could have therapeutic potential. Similarly, targeting RASAL1 in T-cells could enhance anti-tumor immunity. The therapeutic potential of these approaches requires further investigation.

6. Integration with calcium signaling: The physiological contexts in which RASAL1's calcium-responsive shuttling is important, and how this integrates with other calcium-dependent signaling pathways, warrants further study.

References

• [allen-1998-rasal-cloning-abstract]: Allen M, Chu S, Brill S, Stotler C, Buckler A. Restricted tissue expression pattern of a novel human rasGAP-related gene and its murine ortholog. Gene. 1998 Sep 18;218(1-2):17-25. PMID: 9751798. DOI: 10.1016/s0378-1119(98)00394-3

• [sot-2013-rasal-membrane-abstract]: Sot B, Behrmann E, Raunser S, Wittinghofer A. Ras GTPase activating (RasGAP) activity of the dual specificity GAP protein Rasal requires colocalization and C2 domain binding to lipid membranes. Proc Natl Acad Sci U S A. 2013 Jan 2;110(1):111-6. PMID: 23251034. DOI: 10.1073/pnas.1201658110

• [liu-2013-rasal1-thyroid-abstract]: Liu D, Yang C, Bojdani E, Murugan AK, Xing M. Identification of RASAL1 as a major tumor suppressor gene in thyroid cancer. J Natl Cancer Inst. 2013 Nov 6;105(21):1617-27. PMID: 24136889. PMCID: PMC3818169. DOI: 10.1093/jnci/djt249

• [jin-2007-rasal-methylation-abstract]: Jin H, Wang X, Ying J, Wong AH, Cui Y, Srivastava G, Shen ZY, Li EM, Zhang Q, Jin J, Kupzig S, Chan AT, Cullen PJ, Tao Q. Epigenetic silencing of a Ca(2+)-regulated Ras GTPase-activating protein RASAL defines a new mechanism of Ras activation in human cancers. Proc Natl Acad Sci U S A. 2007 Jul 24;104(30):12353-8. PMID: 17640920. PMCID: PMC1941473. DOI: 10.1073/pnas.0700153104

• [thaker-2019-rasal1-zap70-abstract]: Thaker YR, Raab M, Strebhardt K, Rudd CE. GTPase-activating protein Rasal1 associates with ZAP-70 of the TCR and negatively regulates T-cell tumor immunity. Nat Commun. 2019 Oct 22;10(1):4804. PMID: 31641113. PMCID: PMC6805893. DOI: 10.1038/s41467-019-12544-4

• [bechtel-2010-rasal1-kidney-fibrosis-abstract]: Bechtel W, McGoohan S, Zeisberg EM, Müller GA, Kalbber H, Salant DJ, Müller CA, Kalluri R, Zeisberg M. Methylation determines fibroblast activation and fibrogenesis in the kidney. Nat Med. 2010 May;16(5):544-50. PMID: 20418885. PMCID: PMC3106179. DOI: 10.1038/nm.2135

• [deurloo-2024-rasal1-neuronal-abstract]: Deurloo MHS, Eide S, Turlova E, Li Q, Spijker S, Sun H-S, Groffen AJA, Feng Z-P. Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics. Cell Biosci. 2024 Jan 21;14(1):13. PMID: 38246997. PMCID: PMC10800070. DOI: 10.1186/s13578-024-01193-w

• [ohta-2009-rasal1-colorectal-abstract]: Ohta M, Seto M, Ijichi H, Miyabayashi K, Kudo Y, Mohri D, Asaoka Y, Tanaka Y, Maeda S, Kawabe T, Omata M, Koike K. Decreased expression of the RAS-GTPase activating protein RASAL1 is associated with colorectal tumor progression. Gastroenterology. 2009 Jan;136(1):206-16. PMID: 18992247. DOI: 10.1053/j.gastro.2008.09.063

• [sondermann-2010-dual-gap-mechanism-abstract]: Sondermann H. Unravelling the mechanism of dual-specificity GAPs. EMBO J. 2010 Apr 7;29(7):1205-6. PMID: 20186121. PMCID: PMC2857463. DOI: 10.1038/emboj.2010.42

• [simanshu-2019-rasgap-review-abstract]: Ras-Specific GTPase-Activating Proteins—Structures, Mechanisms, and Interactions. Cold Spring Harb Perspect Med. 2019 Mar 1;9(3):a031500. PMCID: PMC6396337. DOI: 10.1101/cshperspect.a031500

• [chen-2014-rasal1-gastric-abstract]: Chen H, Cheng ZY, Pan Y, Wang Z, Liu Y, Zhang JQ. RASAL1 influences the proliferation and invasion of gastric cancer cells by regulating the RAS/ERK signaling pathway. Hum Cell. 2014 Jul;27(3):103-10. PMID: 24531877. DOI: 10.1007/s13577-014-0090-2

• [chen-2013-rasal1-gastric-methylation-abstract]: Chen H, Pan Y, Cheng ZY, Wang Z, Liu Y, Zhao ZJ, Fan H. Hypermethylation and clinicopathological significance of RASAL1 gene in gastric cancer. Asian Pac J Cancer Prev. 2013;14(11):6261-5. PMID: 24377515. DOI: 10.7314/apjcp.2013.14.11.6261

• [qiu-2017-rasal1-liver-fibrosis-abstract]: Qiu W, Weng J, Lan S, Zheng X, Xu L, Huang Z, Chen L, Li H, Cheng M. RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis. Oncotarget. 2017;8(42):73050-73062. DOI: 10.18632/oncotarget.17609

• [xu-2015-rasal1-cardiac-fibrosis-abstract]: Xu X, Tan X, Tampe B, Nyamsuren G, Liu X, Maier LS, Sossalla S, Kalluri R, Zeisberg M, Hasenfuss G, Zeisberg EM. Epigenetic balance of aberrant Rasal1 promoter methylation and hydroxymethylation regulates cardiac fibrosis. Cardiovasc Res. 2015 Mar 1;105(3):279-91. PMID: 25616414. DOI: 10.1093/cvr/cvv015

Citations

1. allen-1998-rasal-cloning-abstract.md
2. bechtel-2010-rasal1-kidney-fibrosis-abstract.md
3. chen-2013-rasal1-gastric-methylation-abstract.md
4. chen-2014-rasal1-gastric-abstract.md
5. deurloo-2024-rasal1-neuronal-abstract.md
6. jin-2007-rasal-methylation-abstract.md
7. liu-2013-rasal1-thyroid-abstract.md
8. ohta-2009-rasal1-colorectal-abstract.md
9. qiu-2017-rasal1-liver-fibrosis-abstract.md
10. simanshu-2019-rasgap-review-abstract.md
11. sondermann-2010-dual-gap-mechanism-abstract.md
12. sot-2013-rasal-membrane-abstract.md
13. thaker-2019-rasal1-zap70-abstract.md
14. xu-2015-rasal1-cardiac-fibrosis-abstract.md

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Plan overview
- We verified the target identity (human RASAL1; UniProt O95294) and domain architecture across recent primary literature, then gathered 2023–2024 sources on function, regulation, disease roles, and applications. We next synthesized mechanistic details and compiled a compact artifact of key facts, followed by a comprehensive narrative with citations and URLs.

Human RASAL1 (O95294): comprehensive research report

1) Key concepts and definitions
- Identity and domains: RASAL1 (RAS protein activator like 1) is a Ras GTPase-activating protein (RasGAP) that contains N‑terminal C2A/C2B domains, a central RasGAP domain, and a C‑terminal pleckstrin homology (PH) domain. This architecture supports Ca2+ and phospholipid-sensing and membrane recruitment that position the RasGAP catalytic module to its substrates at membranes (Cell & Bioscience, Jan 2024: https://doi.org/10.1186/s13578-024-01193-w). The same source and recent reviews classify RASAL1 among tumor‑suppressive RasGAPs (Frontiers in Genetics, Mar 2023: https://doi.org/10.3389/fgene.2023.1124330) (deurloo2024rasal1regulatescalcium pages 1-2, lyu2023roleandmechanism pages 3-5).
- Biochemical function and substrate specificity: RASAL1 accelerates the intrinsic GTP hydrolysis of RAS, converting RAS‑GTP to inactive RAS‑GDP, thereby constraining downstream RAF–MEK–ERK signaling. Its activity is enhanced when associated with the plasma membrane, consistent with the requirement to encounter membrane‑anchored RAS (Cell & Bioscience, 2024; Frontiers in Genetics, 2023) (deurloo2024rasal1regulatescalcium pages 1-2, lyu2023roleandmechanism pages 3-5).
- Subcellular localization: In neurons, Rasal1 is diffusely cytosolic in soma/dendrites/axon but translocates to the plasma membrane in response to intracellular Ca2+ elevations; the C2A domain binds phosphatidylserine and C2B binds phosphoinositides, supporting Ca2+‑dependent membrane association via C2/PH modules (Cell & Bioscience, 2024: https://doi.org/10.1186/s13578-024-01193-w) (deurloo2024rasal1regulatescalcium pages 1-2).

Table: Compact, evidence‑linked summary table of RASAL1 molecular identity, functions, localization, regulatory epigenetics, roles in fibrosis/cancer, therapeutic reversal concepts, and biomarker potential, with 2023–2024 sources cited for each claim.

2) Recent developments and latest research (2023–2024)
- Neuronal mechanisms (2024 primary research): Deurloo et al. showed that neuronal Rasal1 directly interacts with PKC, tubulin, and CaMKII; stabilizes microtubules via tubulin modifications; inhibits dendritic outgrowth/branching; and promotes NMDA receptor–mediated synaptic activity and CaMKII phosphorylation. Live imaging confirmed Ca2+‑dependent membrane recruitment via C2/PH flanking the RasGAP domain (Cell & Bioscience, Jan 2024: https://doi.org/10.1186/s13578-024-01193-w) (deurloo2024rasal1regulatescalcium pages 1-2).
- Fibrosis and epigenetic regulation—kidney focus (2023 review): A state‑of‑the‑art review in Signal Transduction and Targeted Therapy (Mar 2023) synthesized evidence that TGF‑β drives DNMT1‑dependent promoter hypermethylation of RASAL1 in renal fibroblasts, leading to sustained myofibroblast activation and kidney fibrosis; hypermethylated RASAL1 is observed in biopsies from severely fibrotic human kidneys. The review highlights BMP7 as an antagonist capable of reversing RASAL1 hypermethylation and restoring anti‑fibrotic gene expression (Signal Transduction and Targeted Therapy, Mar 2023: https://doi.org/10.1038/s41392-023-01379-7) (huang2023kidneyfibrosisfrom pages 8-9).
- Fibrosis and epigenetic regulation—liver and cross‑organ context (2023 review): In hepatic fibrosis, DNA methylation is a central mechanism; RASAL1 is noted as a RasGAP tumor suppressor commonly downregulated by hypermethylation across fibrotic contexts, reinforcing the generalizability of epigenetic silencing of RASAL1 in fibrosis biology (Frontiers in Genetics, Mar 2023: https://doi.org/10.3389/fgene.2023.1124330) (lyu2023roleandmechanism pages 3-5).
- Demethylation pathways and reversal (2025 review with mechanistic synthesis): A comprehensive nephrology review (2025) reiterates that DNMT1‑mediated promoter methylation of Rasal1 activates renal fibroblasts and promotes renal fibrosis; conversely, BMP7 induces demethylation via TET3 to suppress fibrosis, aligning with earlier preclinical evidence and the 2023 review’s conclusions (Clinical and Experimental Nephrology, Apr 2025: https://doi.org/10.1007/s10157-025-02668-x) (sasaki2025epigenetichistonemodifications pages 3-4).
- Circulating biomarker proposals (2024): A 2024 dissertation‑level analysis proposes methylated circulating RASAL1 DNA as a biomarker of cardiac fibrosis progression and mortality in aortic stenosis, and compiles supporting mechanistic links (e.g., TGFβ/SMAD‑driven or phosphate/HDAC2‑DNMT1‑linked RASAL1 methylation promoting EndMT and fibrosis) (Göttingen repository 2024: https://doi.org/10.53846/goediss-10612) (kanwischer2024methylatedcirculatingdna pages 15-18).

3) Current applications and real‑world implementations
- Biomarker direction of travel: While large clinical validations remain limited, multiple reviews suggest that DNA methylation of anti‑fibrotic genes (including RASAL1) in blood may mirror disease‑relevant tissue methylation status. In kidney disease, whole‑blood methylation profiles may reflect renal methylation, supporting development of circulating methylated RASAL1 assays as noninvasive fibrosis biomarkers (Signal Transduction and Targeted Therapy, 2023: https://doi.org/10.1038/s41392-023-01379-7; dissertation proposing cardiac application, 2024: https://doi.org/10.53846/goediss-10612) (huang2023kidneyfibrosisfrom pages 8-9, kanwischer2024methylatedcirculatingdna pages 15-18).
- Therapeutic concepts: Reviews converge on epigenetic reversal as a therapeutic strategy—DNMT inhibitors (e.g., 5‑azacytidine) and BMP7‑TET demethylation axes to restore RASAL1 and dampen pro‑fibrotic signaling. Preclinical studies summarized in these reviews support feasibility, but clinical translation remains to be established (Signal Transduction and Targeted Therapy, 2023; Clinical and Experimental Nephrology, 2025: URLs above) (huang2023kidneyfibrosisfrom pages 8-9, sasaki2025epigenetichistonemodifications pages 3-4).

4) Expert opinions and analysis
- Mechanistic consensus: Authoritative reviews integrate RASAL1 as an anti‑fibrotic RasGAP frequently silenced by promoter hypermethylation downstream of TGF‑β/DNMT1, enabling persistent RAS–ERK activity and myofibroblast/EndMT programs in kidney (and by extension other fibrotic organs). The reversibility by BMP7 and demethylating agents positions RASAL1 methylation as both a disease driver and a tractable target (Signal Transduction and Targeted Therapy, 2023; Clinical and Experimental Nephrology, 2025) (huang2023kidneyfibrosisfrom pages 8-9, sasaki2025epigenetichistonemodifications pages 3-4).
- Neuronal perspective: The 2024 primary study extends RASAL1 biology into neurodevelopment, revealing Ca2+‑regulated membrane cycling and cytoskeletal control through tubulin interactions—features consistent with a Ca2+‑sensitive RasGAP integrating synaptic signaling with structural maturation (Cell & Bioscience, 2024) (deurloo2024rasal1regulatescalcium pages 1-2).

5) Relevant statistics and data (from recent studies/reviews)
- Kidney fibrosis review reach: The 2023 Signal Transduction and Targeted Therapy review compiling RASAL1 methylation/fibrosis mechanisms has already accrued extensive citations in the field, reflecting broad consensus and adoption (Mar 2023: https://doi.org/10.1038/s41392-023-01379-7) (huang2023kidneyfibrosisfrom pages 8-9).
- Neuronal study dataset: Deurloo et al. provided multi‑modal evidence (imaging, co‑IP, electrophysiology) that Rasal1 modulates dendritic morphology and synaptic function, with Western blot detection in mouse hippocampus and cortex and dynamic Ca2+‑dependent membrane localization (Jan 2024: https://doi.org/10.1186/s13578-024-01193-w) (deurloo2024rasal1regulatescalcium pages 1-2).
- Biomarker concept evidence: The 2024 dissertation reports associations between methylated cfDNA and fibrosis progression/mortality in aortic stenosis patients as an exploratory framework, highlighting potential clinical utility pending peer‑reviewed validation (2024: https://doi.org/10.53846/goediss-10612) (kanwischer2024methylatedcirculatingdna pages 15-18).

Functional annotation summary
- Primary function: Ras GTPase‑activating protein that promotes GTP hydrolysis on RAS, restraining RAF–MEK–ERK signaling. Activity aligns with membrane association via Ca2+‑regulated C2/PH modules (Cell & Bioscience, 2024; Frontiers in Genetics, 2023) (deurloo2024rasal1regulatescalcium pages 1-2, lyu2023roleandmechanism pages 3-5).
- Localization: Cytosolic with Ca2+‑dependent translocation to the plasma membrane; C2A binds phosphatidylserine and C2B binds phosphoinositides, supporting a Ca2+‑sensing membrane recruitment mechanism (Cell & Bioscience, 2024) (deurloo2024rasal1regulatescalcium pages 1-2).
- Pathways: Negative regulator of RAS→RAF–MEK–ERK; epigenetic silencing (DNMT1‑mediated RASAL1 promoter hypermethylation) elevates RAS signaling and fosters fibrogenic programs including myofibroblast activation and EndMT in kidney; BMP7/TET demethylation can reverse these states in preclinical synthesis (Signal Transduction and Targeted Therapy, 2023; Clinical and Experimental Nephrology, 2025) (huang2023kidneyfibrosisfrom pages 8-9, sasaki2025epigenetichistonemodifications pages 3-4).
- Disease roles: Anti‑fibrotic RasGAP frequently downregulated by promoter hypermethylation across fibrotic contexts (kidney, with cross‑organ generalization to liver and heart in reviews/dissertation); potential tumor‑suppressive role inferred from RasGAP function and literature synthesis (Frontiers in Genetics, 2023; Signal Transduction and Targeted Therapy, 2023; dissertation, 2024) (lyu2023roleandmechanism pages 3-5, huang2023kidneyfibrosisfrom pages 8-9, kanwischer2024methylatedcirculatingdna pages 15-18).
- Applications: Early evidence supports methylated RASAL1 as a circulating biomarker of fibrotic burden/prognosis (cardiac aortic stenosis), with kidney-directed noninvasive methylation profiling proposed; therapeutic reversal via demethylating strategies remains preclinical/early translational (Signal Transduction and Targeted Therapy, 2023; dissertation, 2024; Clinical and Experimental Nephrology, 2025) (huang2023kidneyfibrosisfrom pages 8-9, kanwischer2024methylatedcirculatingdna pages 15-18, sasaki2025epigenetichistonemodifications pages 3-4).

Verification of the requested identity and scope
- The gene symbol RASAL1 and the human protein reviewed here match the UniProt O95294 identity and domain arrangement (C2/C2, RasGAP, PH) reflected in the 2024 primary study, ensuring the correct human target was investigated (Cell & Bioscience, 2024: https://doi.org/10.1186/s13578-024-01193-w) (deurloo2024rasal1regulatescalcium pages 1-2).

References (with URLs and dates)
- Deurloo MHS et al. Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics. Cell & Bioscience. Jan 2024. https://doi.org/10.1186/s13578-024-01193-w (deurloo2024rasal1regulatescalcium pages 1-2)
- Huang R‑s, Fu P, Ma L. Kidney fibrosis: from mechanisms to therapeutic medicines. Signal Transduction and Targeted Therapy. Mar 2023. https://doi.org/10.1038/s41392-023-01379-7 (huang2023kidneyfibrosisfrom pages 8-9)
- Kanwischer L. Methylated circulating DNA as a biomarker for cardiac fibrosis progression and mortality in aortic stenosis patients. 2024. https://doi.org/10.53846/goediss-10612 (kanwischer2024methylatedcirculatingdna pages 15-18)
- Sasaki K, Masaki T. Epigenetic histone modifications in kidney disease and epigenetic memory. Clinical and Experimental Nephrology. Apr 2025. https://doi.org/10.1007/s10157-025-02668-x (sasaki2025epigenetichistonemodifications pages 3-4)
- Lyu S‑Y et al. Role and mechanism of DNA methylation and its inhibitors in hepatic fibrosis. Frontiers in Genetics. Mar 2023. https://doi.org/10.3389/fgene.2023.1124330 (lyu2023roleandmechanism pages 3-5)

Limitations and open questions
- Most biomarker evidence for methylated RASAL1 is still exploratory; large independent clinical validations are needed. Therapeutic demethylation strategies targeting RASAL1 (e.g., DNMT inhibitors/BMP7) remain at a preclinical/early translational stage and will require trials for safety/efficacy. Neuronal roles require in vivo validation and dissection of Ras‑dependent versus cytoskeletal interaction‑dependent mechanisms (deurloo2024rasal1regulatescalcium pages 1-2, huang2023kidneyfibrosisfrom pages 8-9, kanwischer2024methylatedcirculatingdna pages 15-18, sasaki2025epigenetichistonemodifications pages 3-4).

References

1. (deurloo2024rasal1regulatescalcium pages 1-2): M. H. S. Deurloo, S. Eide, E. Turlova, Q. Li, S. Spijker, H.-S. Sun, A. J. A. Groffen, and Z.-P. Feng. Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics. Cell & Bioscience, Jan 2024. URL: https://doi.org/10.1186/s13578-024-01193-w, doi:10.1186/s13578-024-01193-w. This article has 5 citations and is from a peer-reviewed journal.

2. (lyu2023roleandmechanism pages 3-5): Shi-Yi Lyu, Wang Xiao, Guang-Zu Cui, Cheng Yu, Huan Liu, Min Lyu, Qian-Ya Kuang, En-Hua Xiao, and Yong-Heng Luo. Role and mechanism of dna methylation and its inhibitors in hepatic fibrosis. Frontiers in Genetics, Mar 2023. URL: https://doi.org/10.3389/fgene.2023.1124330, doi:10.3389/fgene.2023.1124330. This article has 16 citations and is from a peer-reviewed journal.

3. (huang2023kidneyfibrosisfrom pages 8-9): Rong-shuang Huang, P. Fu, and Liang Ma. Kidney fibrosis: from mechanisms to therapeutic medicines. Signal Transduction and Targeted Therapy, Mar 2023. URL: https://doi.org/10.1038/s41392-023-01379-7, doi:10.1038/s41392-023-01379-7. This article has 567 citations and is from a peer-reviewed journal.

4. (sasaki2025epigenetichistonemodifications pages 3-4): Kensuke Sasaki and Takao Masaki. Epigenetic histone modifications in kidney disease and epigenetic memory. Clinical and experimental nephrology, Apr 2025. URL: https://doi.org/10.1007/s10157-025-02668-x, doi:10.1007/s10157-025-02668-x. This article has 2 citations and is from a peer-reviewed journal.

5. (kanwischer2024methylatedcirculatingdna pages 15-18): Leon Kanwischer. Methylated circulating dna as a biomarker for cardiac fibrosis progression and mortality in aortic stenosis patients. ArXiv, 2024. URL: https://doi.org/10.53846/goediss-10612, doi:10.53846/goediss-10612. This article has 0 citations.

Citations

1. lyu2023roleandmechanism pages 3-5
2. huang2023kidneyfibrosisfrom pages 8-9
3. sasaki2025epigenetichistonemodifications pages 3-4
4. kanwischer2024methylatedcirculatingdna pages 15-18
5. https://doi.org/10.1186/s13578-024-01193-w
6. https://doi.org/10.3389/fgene.2023.1124330
7. https://doi.org/10.1038/s41392-023-01379-7
8. https://doi.org/10.1007/s10157-025-02668-x
9. https://doi.org/10.53846/goediss-10612
10. https://doi.org/10.1038/s41392-023-01379-7;
11. https://doi.org/10.1186/s13578-024-01193-w,
12. https://doi.org/10.3389/fgene.2023.1124330,
13. https://doi.org/10.1038/s41392-023-01379-7,
14. https://doi.org/10.1007/s10157-025-02668-x,
15. https://doi.org/10.53846/goediss-10612,

RASAL1 (Ras Protein Activator Like 1) – Function and Biological Role in Humans

Background and Key Function

RASAL1 (UniProt O95294) is a human gene encoding a Ras GTPase-activating protein (RasGAP) that serves as a critical negative regulator of Ras signaling. Ras proteins (H-Ras, K-Ras, N-Ras) act as molecular switches cycling between an active GTP-bound state and an inactive GDP-bound state, controlling pathways for cell growth, differentiation, and survival (pmc.ncbi.nlm.nih.gov). RASAL1 accelerates Ras’s intrinsic GTP hydrolysis, converting active Ras–GTP to inactive Ras–GDP and thereby terminating Ras signaling (pmc.ncbi.nlm.nih.gov). This GAP activity “switches off” Ras, allowing tight control of Ras-driven processes such as cell proliferation and differentiation (geneglobe.qiagen.com). Notably, RASAL1 belongs to the GAP1 family of RasGAPs and was first described in 1998 as a highly conserved RasGAP-related protein with a restricted tissue expression pattern (cellandbioscience.biomedcentral.com) (cellandbioscience.biomedcentral.com). Biochemically, RASAL1 has dual substrate specificity, able to stimulate GTP hydrolysis on Ras as well as on the closely related Rap1 GTPase (cellandbioscience.biomedcentral.com) (pmc.ncbi.nlm.nih.gov). This dual Ras/Rap GAP activity is uncommon – RASAL1 (also called GAP1(RasAL)) and a related protein CAPRI were shown to inactivate both Ras and Rap, whereas many other RasGAPs act only on Ras (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). By inactivating normal Ras p21 proteins (but not certain oncogenic mutant Ras that resist GAPs) (geneglobe.qiagen.com), RASAL1 functions as a suppressor of Ras signaling, ensuring Ras activity is restrained once a signal has been propagated (pmc.ncbi.nlm.nih.gov). This role is analogous to applying a “brake” on Ras-driven pathways, which is vital for normal cell signaling homeostasis.

Structural Features and Regulation

The RASAL1 protein is ~804 amino acids and contains multiple defined domains that govern its function and subcellular targeting. Its central region is a conserved RasGAP domain responsible for binding Ras–GTP and inserting a catalytic “arginine finger” into Ras’s active site to stimulate GTP hydrolysis (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Flanking this catalytic domain are regulatory lipid-binding modules that confer Ca²⁺-dependent membrane localization (cellandbioscience.biomedcentral.com). At the N-terminus, RASAL1 carries two C2 domains (C2A and C2B), which are lipid-binding motifs sensitive to calcium. The C2A domain binds phosphatidylserine and the C2B domain binds phosphoinositides, such that when intracellular Ca²⁺ levels rise, these domains cooperate to recruit RASAL1 from the cytosol to the inner face of the plasma membrane (cellandbioscience.biomedcentral.com). This Ca²⁺-dependent membrane translocation is essential for function: Ras itself is membrane-anchored, so RASAL1 must co-localize at the membrane to engage and inactivate Ras (cellandbioscience.biomedcentral.com). Consistently, only during periods when RASAL1 is membrane-bound does it turn off Ras signaling (pmc.ncbi.nlm.nih.gov). RASAL1 also possesses a C-terminal pleckstrin homology (PH) domain, which binds membrane phosphoinositides and works in concert with the C2 domains to stabilize RASAL1 at the membrane upon Ca²⁺ signaling (cellandbioscience.biomedcentral.com). Through this multi-domain architecture, RASAL1 acts as a Ca²⁺-regulated Ras GAP “sensor”: it remains in the cytosol under resting conditions, but bursts of intracellular Ca²⁺ trigger its rapid and reversible relocation to the plasma membrane (cellandbioscience.biomedcentral.com) (cellandbioscience.biomedcentral.com). This was vividly demonstrated in live-cell imaging, where RASAL1 tagged with EGFP showed diffuse cytosolic distribution at rest, but within seconds of a calcium spike it concentrated at the cell periphery, then cycled back off with calcium subsidence (cellandbioscience.biomedcentral.com). Such oscillatory movements enable RASAL1 to decode complex Ca²⁺ signals – it synchronizes with repetitive Ca²⁺ spikes by repeatedly binding the membrane and inactivating Ras in step, effectively linking the frequency of Ca²⁺ transients to the amplitude of Ras activity (pmc.ncbi.nlm.nih.gov). This unique regulation distinguishes RASAL1 from other RasGAPs that are constitutively membrane-bound (like p120^GAP) and allows cross-talk between calcium signaling and Ras pathways.

In terms of cellular localization, RASAL1 is predicted to be an intracellular protein and is observed in both the cytosol and plasma membrane, with enrichment at cell peripheries/junctions upon activation (www.proteinatlas.org). The dynamic Ca²⁺-mediated membrane targeting is a key regulatory mechanism: a 2013 structural study confirmed that RASAL1’s RasGAP activity strictly requires lipid membrane association via its C2 domains (cellandbioscience.biomedcentral.com). Thus, calcium acts as an allosteric activator of RASAL1 by driving its co-localization with Ras. This regulation is physiologically significant in cell types that experience calcium bursts (e.g. neurons, endocrine cells), as discussed below.

Involvement in Ras Signaling Pathways

As a RasGAP, RASAL1 directly impacts major signaling cascades downstream of Ras. Active GTP-loaded Ras triggers multiple effector pathways – most prominently the RAF–MEK–ERK mitogen-activated protein kinase (MAPK) cascade and the PI3K–AKT–mTOR pathway – which together regulate cell proliferation, differentiation, survival, cytoskeleton dynamics and metabolism (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). By accelerating the conversion of Ras-GTP to Ras-GDP, RASAL1 attenuates these pathways once they have been initiated. For example, Ras activation of the Raf/MEK/ERK pathway leads to ERK-mediated phosphorylation of various targets including microtubule-associated proteins, influencing microtubule stability and cell cycle progression (cellandbioscience.biomedcentral.com). RASAL1, by shutting off Ras, will shorten the duration or intensity of ERK signaling, thereby modulating outcomes like cell proliferation and cytoskeletal remodeling. Similarly, Ras activates class I PI3-kinases, resulting in AKT kinase signaling; RASAL1’s action terminates Ras input into PI3K, helping to restrain the PI3K–AKT pathway. A recent large-scale analysis underscores RASAL1’s importance in this pathway: loss-of-function alterations in RASAL1 lead to aberrant PI3K–AKT activation, analogous to loss of the PI3K pathway brake PTEN. In a 2024 study with ~9,900 human tumors, concurrent RASAL1 inactivation and PTEN loss were associated with significantly higher AKT activity and more aggressive cancer progression (hazard ratio ~1.6), whereas either lesion alone was less impactful (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). This indicates RASAL1 and PTEN normally cooperate to keep the PI3K–AKT pathway in check – RASAL1 prevents excessive Ras-driven PI3K activation at the membrane, while PTEN antagonizes PI3K signaling by dephosphorylating PIP₃ in the cytosol (pubmed.ncbi.nlm.nih.gov). When both brakes fail, Ras-PI3K signaling runs unchecked, driving malignancy (pubmed.ncbi.nlm.nih.gov).

RASAL1 may also interface with other signaling branches. Notably, Ras signaling is known to cross-talk with cyclic AMP (cAMP) pathways in certain contexts (for instance, via Ras effects on adenylate cyclase or through the Ras-related Rap1 which is activated by cAMP). RASAL1 has been described as a “probable inhibitory regulator of the Ras–cAMP pathway”, hinting that it might temper Ras’s influence on cAMP-dependent processes (www.genecards.org). In endocrine cells like thyroid follicular cells and adrenal medulla (where RASAL1 is strongly expressed) (www.genecards.org), hormonal signals often use cAMP as a second messenger; RASAL1 could modulate responses in these cells by linking Ras activity to cAMP signaling outcomes. In hepatic stellate cells (liver fibroblasts), recent work found that RASAL1 can interact with the angiotensin II receptor (a GPCR) and influence downstream PKA–LKB1–AMPK signaling, suggesting RASAL1’s effects may extend beyond the classic Ras→ERK/AKT pathways to other signaling modules (www.oncotarget.com). These findings are cell-type specific, but they illustrate that by controlling Ras and even Rap GTPases, RASAL1 can broadly influence signaling networks, acting as a node where calcium, GPCR, and growth factor pathways converge on Ras.

Biological Roles in Cells and Tissues

Through its regulation of Ras activity, RASAL1 impacts a range of biological processes, especially those involving cell proliferation, differentiation, and morphology. Cell Growth and Differentiation: By dampening Ras/MAPK signaling, RASAL1 helps control normal cell proliferation and differentiation signals (geneglobe.qiagen.com). When Ras is appropriately inactivated, cells can exit the growth cycle or differentiate in response to cues. Conversely, loss of RASAL1 leads to prolonged Ras signaling, which can cause hyper-proliferation or aberrant differentiation. For example, experiments show that introducing RASAL1 into Ras-driven cancer cells curtails their growth: forced expression of RASAL1 in RASAL1-deficient gastric carcinoma cells significantly suppressed their proliferation and tumorigenic transformation ability (cellandbioscience.biomedcentral.com). This supports that RASAL1’s normal role is to restrain unchecked cell division.

Tissue Distribution: RASAL1 is expressed in many tissues but exhibits especially high or selective expression in certain cell types, hinting at specialized functions. Early studies noted enriched RASAL1 expression in the brain, in kidney (medulla region), and in endocrine glands such as the thyroid follicular cells and adrenal zona glomerulosa/medulla (cellandbioscience.biomedcentral.com) (www.genecards.org). The Human Protein Atlas reports RASAL1 mRNA as “tissue-enhanced” in parathyroid and salivary glands and protein localized in cytoplasm and plasma membrane in multiple cell types (www.proteinatlas.org). In the brain, RASAL1 is notably abundant in neurons – a recent analysis confirmed strong expression in mouse hippocampus and cortex (cellandbioscience.biomedcentral.com). The high neuronal expression led researchers to investigate RASAL1’s role in the nervous system, revealing new functions beyond its tumor suppressor identity. In 2024, Wang et al. showed that RASAL1 is active in developing hippocampal neurons, where it influences neuronal maturation and synaptic function (cellandbioscience.biomedcentral.com) (cellandbioscience.biomedcentral.com). They found RASAL1 distributes throughout the neuron (soma, dendrites, axon) and translocates to synaptic membranes upon NMDA receptor-triggered Ca²⁺ influx (cellandbioscience.biomedcentral.com) (cellandbioscience.biomedcentral.com). Neuronal Structure and Plasticity: Intriguingly, RASAL1 was observed to bind directly to key regulators of the cytoskeleton and synaptic plasticity – protein kinase C (PKC), CaMKII (Ca²⁺/calmodulin-dependent kinase II), and tubulin – implying it has scaffolding or adapter functions in addition to Ras inactivation (cellandbioscience.biomedcentral.com). By interacting with tubulin, RASAL1 promoted microtubule stability and curtailed excessive dendritic branching during neuron development (cellandbioscience.biomedcentral.com). Neurons lacking RASAL1 had more exuberant dendrite outgrowth, whereas RASAL1 presence constrained neurite extension, consistent with Ras–ERK’s known role in stabilizing microtubules and limiting branching (cellandbioscience.biomedcentral.com) (cellandbioscience.biomedcentral.com). On the other hand, RASAL1 enhanced certain aspects of synaptic activity: it facilitated NMDA receptor-mediated Ca²⁺ signaling and downstream CaMKII phosphorylation, which are important for synaptic strengthening (cellandbioscience.biomedcentral.com). These findings suggest RASAL1 plays a dual role in neurons – it restrains structural growth of dendrites (possibly by inhibiting overactive Ras or Rho pathways that drive cytoskeletal remodeling) while tuning Ca²⁺-dependent signaling at synapses to modulate plasticity (cellandbioscience.biomedcentral.com). In summary, beyond controlling cell proliferation, RASAL1 contributes to cell morphology and differentiation. Another example is in pigment cells: RASAL1 is reported to participate in dendrite formation by melanocytes (www.genecards.org), the cells that extend dendritic processes to distribute melanin to keratinocytes. Melanocyte dendritogenesis involves Ras and Rho family signals controlling the actin/microtubule cytoskeleton (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov), and RASAL1’s ability to modulate Ras (and possibly Rap1 or Rac1 indirectly) likely influences this process. Thus, whether in neurons or melanocytes, RASAL1 helps fine-tune the balance of signaling required for proper cell shape and connectivity, linking extracellular stimuli (e.g. Ca²⁺-mobilizing signals or hormones) to cytoskeletal outcomes.

It’s worth noting that RASAL1 responds to physiological signals that elevate intracellular Ca²⁺, such as certain neurotransmitters, hormones, or growth factors. Many G-protein coupled receptors (GPCRs) and receptor tyrosine kinases can provoke Ca²⁺ release via IP₃ or calcium influx (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). RASAL1, by sensing those Ca²⁺ transients, provides a feedback loop: for instance, a GPCR that raises Ca²⁺ will activate RASAL1, which in turn dampens Ras. In this way, RASAL1 acts as a signal integrator, and possibly a homeostatic safeguard, preventing runaway Ras activation in the face of repetitive stimuli. Researchers have characterized RASAL1 and its paralog CAPRI as “Ca²⁺-regulated Ras GAPs that decode Ca²⁺ oscillation frequency” to modulate downstream gene expression and cell fate decisions (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). This mode of regulation may be especially important in excitable cells (neurons, muscle) and secretory cells that experience oscillatory Ca²⁺ signals.

Clinical and Pathological Significance

Given its central role in downregulating Ras, it is not surprising that RASAL1 has emerged as a bona fide tumor suppressor gene and a factor in diseases characterized by abnormal Ras pathway activation. In healthy cells, RASAL1 keeps Ras signaling in check; if RASAL1 is lost or silenced, Ras can remain hyperactive even in the absence of mutations in Ras itself. This has been observed in multiple cancers. Cancer and RasAL1: A landmark study in 2013 identified RASAL1 as a major tumor suppressor frequently inactivated in thyroid carcinoma (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Among 13 negative Ras pathway regulators screened, RASAL1 stood out as frequently silenced by epigenetic and genetic mechanisms in thyroid tumors, particularly in follicular thyroid carcinoma (FTC) and anaplastic thyroid carcinoma (ATC) (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). RASAL1’s promoter was found hypermethylated in ~32% of FTC and 33% of ATC cases, and a subset of aggressive tumors also harbored inactivating RASAL1 missense mutations (mutations were seen in ~5% of FTC and ~17% of ATC) (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Notably, these RASAL1 alterations were largely mutually exclusive with the classical oncogenic mutations in the Ras/MAPK/PI3K pathways (such as RAS or BRAF mutations) (pmc.ncbi.nlm.nih.gov). In other words, cancers that did not mutate Ras itself often instead had RASAL1 silenced, achieving a similar outcome of unchecked Ras pathway signaling (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). This firmly established RASAL1 loss as an “alternative mechanism of Ras activation” in tumors (pmc.ncbi.nlm.nih.gov). Indeed, RASAL1 was the only RasGAP gene found completely methylated and silenced across a panel of thyroid cancer cell lines, underlining its unique importance in that context (pmc.ncbi.nlm.nih.gov). Functional assays supported its tumor-suppressive role: restoration of RASAL1 in thyroid cancer cells suppressed MAPK and PI3K signaling and curtailed tumorigenic growth, whereas cancer-associated mutations in RASAL1 abrogated these effects (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov).

Beyond thyroid cancer, epigenetic silencing or loss of RASAL1 is a recurring theme in many malignancies. For example, RASAL1 downregulation (often via promoter hypermethylation) has been reported in colon cancer, gastric cancer, liver cancer, bladder cancer, and others (www.oncotarget.com). In colorectal and gastric tumors, studies have found frequent RASAL1 promoter hypermethylation correlating with low expression, and enforced re-expression of RASAL1 in cell lines from these cancers can inhibit their proliferation (www.oncotarget.com) (cellandbioscience.biomedcentral.com). In hepatocellular carcinoma, loss of RasGAPs including RASAL1 has been linked to elevated wild-type Ras activity driving growth (cellandbioscience.biomedcentral.com). In one oncogenomic analysis of The Cancer Genome Atlas (TCGA) data (33 cancer types), RASAL1 genetic alterations (deletions or mutations) were found in a significant fraction of tumors and often co-occurred with alterations in other tumor suppressors; strikingly, co-loss of RASAL1 and PTEN was associated with substantially worse patient outcomes, as mentioned earlier (pubmed.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov). This suggests a synergy in oncogenesis when Ras signaling is unleashed by RASAL1 loss and PI3K signaling is unchecked by PTEN loss. Consistent with a tumor suppressor, germline mutations in RASAL1 have also been discovered in rare cases. A 2014 report found deleterious RASAL1 germline mutations in individuals with Cowden syndrome (an inherited cancer syndrome typically caused by PTEN mutations) who developed thyroid cancers despite lacking PTEN mutations (pmc.ncbi.nlm.nih.gov). The fact that RASAL1 germline variants can predispose to thyroid tumors (especially follicular-type) further underscores RASAL1’s role as a critical Ras pathway inhibitor in vivo (pmc.ncbi.nlm.nih.gov). Overall, the evidence from human cancers positions RASAL1 alongside better-known Ras pathway tumor suppressors like NF1 (neurofibromin) and RASA1/p120^GAP, wherein its inactivation removes a restraint on Ras, contributing to oncogenic signaling (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov).

Importantly, the method of RASAL1 inactivation in disease is often epigenetic (promoter DNA hypermethylation) rather than DNA mutation. This has two implications: (1) it may be reversible or targetable by epigenetic therapies, and (2) it can serve as a diagnostic marker. Methylation of the RASAL1 promoter has been proposed as a biomarker in certain cancers and pathological conditions. For instance, in thyroid neoplasms, RASAL1 methylation status distinguished malignant from benign tumors in some studies (pmc.ncbi.nlm.nih.gov). In circulating tumor DNA, hypermethylated RASAL1 sequences could potentially indicate the presence of a Ras-driven tumor, although more research is needed in this area.

Beyond cancer, RASAL1 has a pivotal role in fibrotic diseases, which are characterized by pathological, persistent activation of fibroblasts. Fibroblast activation (myofibroblast transformation) is normally transient during wound healing, but in fibrosis it becomes self-sustaining, leading to excessive scar tissue deposition in organs. Groundbreaking research in 2010 found that epigenetic silencing of RASAL1 underlies this abnormal fibroblast persistence in the kidney (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). In models of chronic kidney injury, fibroblasts from fibrotic kidneys showed hypermethylation of the RASAL1 promoter and loss of RASAL1 expression, which was directly linked to continuously high Ras–ERK signaling and fibroblast proliferation (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Normally, as a tissue heals, fibroblasts revert to quiescence in part because Ras activity diminishes; but if RASAL1 is permanently shut off by methylation, Ras remains active and keeps the fibroblasts in a pro-fibrotic state (pmc.ncbi.nlm.nih.gov). This mechanism was confirmed by treating fibrotic mice with DNA methylation inhibitors: pharmacologically demethylating the RASAL1 gene reactivated its expression and dramatically reduced organ fibrosis (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Specifically, administration of 5-azacytidine (a DNA demethylating agent) to mice with folic acid–induced renal fibrosis restored RASAL1 levels in kidney fibroblasts and was associated with less collagen deposition and better kidney function than in untreated fibrotic mice (pmc.ncbi.nlm.nih.gov). Similarly, a 2014 study found that low-dose hydralazine (an FDA-approved drug) can induce TET3-dependent demethylation of RASAL1, partially rescuing its expression and attenuating kidney fibrosis in rodents (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Perhaps most convincingly, transgenic mice engineered to overexpress RASAL1 (via a doxycycline-inducible transgene) were protected from fibrosis: forcing RASAL1 back “on” in activated fibroblasts normalized their overzealous proliferation and reduced fibrogenesis in a unilateral kidney obstruction model (pmc.ncbi.nlm.nih.gov). These findings make RASAL1 a key therapeutic target in fibrosis. They reveal that pro-fibrotic factors like TGF-β drive RASAL1 silencing (TGF-β was shown to induce RASAL1 promoter methylation via DNMT1 in fibroblasts (www.oncotarget.com) (pmc.ncbi.nlm.nih.gov)), and conversely anti-fibrotic factors like BMP7 counteract this (BMP7 prevented RASAL1 hypermethylation and blunted cardiac and renal fibrosis in experimental models (www.oncotarget.com) (pmc.ncbi.nlm.nih.gov)). The epigenetic balance of RASAL1 thus determines fibroblast behavior: transient, unmethylated RASAL1 suppression allows normal wound repair, whereas stable RASAL1 hypermethylation locks fibroblasts in an active state leading to chronic fibrosis (pmc.ncbi.nlm.nih.gov). Clinically, this has spurred interest in detecting RASAL1 methylation in tissues as a prognostic indicator of fibrotic progression, and in designing therapies to reactivate RASAL1. While direct RASAL1 gene therapy is not yet available, the proof-of-concept with demethylating drugs and gene induction in animals is promising (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov).

Finally, RASAL1’s relevance extends to other conditions. For example, hypermethylation of RASAL1 has been observed in choriocarcinoma (a trophoblastic cancer), where it was linked to chemotherapy resistance and tumor progression (pmc.ncbi.nlm.nih.gov). In that study, restoring RASAL1 expression or preventing its hypermethylation (via TET2-mediated DNA demethylation) resensitized cancer cells to drugs and slowed their growth (pmc.ncbi.nlm.nih.gov). This suggests loss of RASAL1 confers survival advantages to cells under therapeutic stress, again through sustaining Ras/PI3K signaling. There is also emerging evidence that hypoxia and other stresses can alter RASAL1 epigenetics in certain cell types (e.g. trabecular meshwork cells in glaucoma) (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov), hinting that RASAL1 is a nexus in cellular responses beyond classical Ras-driven diseases.

Conclusion and Future Perspectives

RASAL1 is a multifaceted protein that lies at the intersection of signaling pathways controlling cell growth, shape, and fate. In essence, it is a Ca²⁺-regulated “off-switch” for Ras and related small GTPases, ensuring that Ras activity is properly curtailed after it has delivered proliferative or differentiation signals. Current understanding, reinforced by the latest research, paints RASAL1 as crucial for preventing pathological Ras hyperactivity – whether in the context of neoplastic transformation or fibrotic disease. Its regulation by calcium and complex domain structure enable RASAL1 to integrate diverse signals, from neuronal firing to hormonal stimulation, into appropriate Ras signaling outputs. Real-world applications of this knowledge are beginning to take shape. In oncology, RASAL1 methylation status is being explored as a diagnostic marker and as a stratification factor (e.g. patients with RASAL1-silenced tumors might benefit from Ras pathway inhibitors or epigenetic therapies). In fibrosis, RASAL1 reactivation strategies (such as low-dose DNA methylation inhibitors or TGF-β pathway modulators like BMP7) offer a novel therapeutic angle to halt or reverse organ scarring (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Furthermore, the discovery of RASAL1’s role in neural development and function opens new questions about its involvement in neurological disorders where Ras signaling or Ca²⁺ homeostasis is disrupted. Ongoing research in 2023–2024 continues to shed light on these aspects – for instance, delineating how RASAL1’s interaction with cytoskeletal regulators affects learning and memory, or how RASAL1 loss in stromal cells might contribute to tumor microenvironment changes. As one authoritative review aptly summarized, genetic or epigenetic inactivation of negative Ras modulators like RASAL1 represents an important alternative mechanism of disease, analogous to direct oncogene activation (pmc.ncbi.nlm.nih.gov). In the case of RASAL1, understanding and harnessing this mechanism holds promise for new clinical interventions in cancer and fibrosis, making this once “hidden” RasGAP an exciting focus of translational research.

References: (Each reference corresponds to cited information in the text above)

Citations

1. AnnotationURLCitation(end_index=639, start_index=476, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=various%20modulators%20that%20function%20as,development%20of%20a%20variety%20of')
2. AnnotationURLCitation(end_index=890, start_index=776, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=RASAL1%2C%20a%20RAS%20GTPase,4')
3. AnnotationURLCitation(end_index=1151, start_index=1024, title='RASAL1 [Human] | GeneGlobe', type='url_citation', url='https://geneglobe.qiagen.com/us/knowledge/gene/ENSG00000111344#:~:text=activating%20proteins,provided')
4. AnnotationURLCitation(end_index=1467, start_index=1328, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=References')
5. AnnotationURLCitation(end_index=1625, start_index=1468, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=1,1998%3B218%3A17%E2%80%9325')
6. AnnotationURLCitation(end_index=1989, start_index=1771, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=Rasal1%2C%20first%20described%20to%20our,in%20neuronal%20processes%20remains%20unexplored')
7. AnnotationURLCitation(end_index=2125, start_index=1990, title='GAP1 Family Members Constitute Bifunctional Ras and Rap GTPase-activating Proteins - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC1904491/#:~:text=domain,association%20with%20the%20plasma%20membrane')
8. AnnotationURLCitation(end_index=2454, start_index=2319, title='GAP1 Family Members Constitute Bifunctional Ras and Rap GTPase-activating Proteins - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC1904491/#:~:text=domain,association%20with%20the%20plasma%20membrane')
9. AnnotationURLCitation(end_index=2613, start_index=2455, title='GAP1 Family Members Constitute Bifunctional Ras and Rap GTPase-activating Proteins - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC1904491/#:~:text=In%20mammalian%20cells%2C%20Ras,site%20of%20Ras%2C%20thereby%20stabilizing')
10. AnnotationURLCitation(end_index=2867, start_index=2711, title='RASAL1 [Human] | GeneGlobe', type='url_citation', url='https://geneglobe.qiagen.com/us/knowledge/gene/ENSG00000111344#:~:text=The%20protein%20encoded%20by%20this,Alternatively%20spliced')
11. AnnotationURLCitation(end_index=3129, start_index=2994, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=the%20active%20GTP,in%20the%20context%20of%20recent')
12. AnnotationURLCitation(end_index=3769, start_index=3605, title='GAP1 Family Members Constitute Bifunctional Ras and Rap GTPase-activating Proteins - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC1904491/#:~:text=hydrolysis%20in%20all%20other%20Ras,asparagine%20thumb%2C%20to%20stimulate%20GTP')
13. AnnotationURLCitation(end_index=3899, start_index=3770, title='GAP1 Family Members Constitute Bifunctional Ras and Rap GTPase-activating Proteins - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC1904491/#:~:text=distinct,the%20glutamine%20residue%20in%20Ras')
14. AnnotationURLCitation(end_index=4222, start_index=4022, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=The%20structure%20of%20Rasal1%20gives,domain%2C%20which%20operates%20as')
15. AnnotationURLCitation(end_index=4746, start_index=4576, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=motifs%20%5B7%20%5D.%20The%20N,15%2C%2013')
16. AnnotationURLCitation(end_index=5081, start_index=4923, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=11,2013%3B110%3A111%E2%80%936')
17. AnnotationURLCitation(end_index=5314, start_index=5182, title='Identification of a Ras GTPase-activating protein regulated by receptor-mediated Ca2+ oscillations - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC394250/#:~:text=repetitive%20Ca,and%20the%20regulation%20of%20Ras')
18. AnnotationURLCitation(end_index=5676, start_index=5524, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=phospholipid,15%2C%2013')
19. AnnotationURLCitation(end_index=6123, start_index=5924, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=molecular%20tools,synaptic%20activity%20and%20CaMKII%20phosphorylation')
20. AnnotationURLCitation(end_index=6291, start_index=6124, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=basal%20conditions%20%28Fig,40%C2%A0mM')
21. AnnotationURLCitation(end_index=6711, start_index=6544, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=basal%20conditions%20%28Fig,40%C2%A0mM')
22. AnnotationURLCitation(end_index=7152, start_index=6986, title='Identification of a Ras GTPase-activating protein regulated by receptor-mediated Ca2+ oscillations - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC394250/#:~:text=induction%20of%20selective%20cellular%20functions,and%20the%20regulation%20of%20Ras')
23. AnnotationURLCitation(end_index=7724, start_index=7550, title='Protein structure - RASAL1 - The Human Protein Atlas', type='url_citation', url='https://www.proteinatlas.org/ENSG00000111344-RASAL1/structure%2Binteraction#:~:text=cluster%20%28RNA%29%5E%7Bi%7D%20Parathyroid%20gland%20,113136239')
24. AnnotationURLCitation(end_index=8092, start_index=7934, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=11,2013%3B110%3A111%E2%80%936')
25. AnnotationURLCitation(end_index=8914, start_index=8751, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=various%20modulators%20that%20function%20as,development%20of%20a%20variety%20of')
26. AnnotationURLCitation(end_index=9091, start_index=8915, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=include%20RAF%E2%86%92%20MEK%20%E2%86%92%20ERK,PI3K%20pathway%2C%20genetic%20or%20epigenetic')
27. AnnotationURLCitation(end_index=9644, start_index=9427, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=several%20pathways%20involved%20in%20cell,significant%20roles%20in%20remodelling%20spine')
28. AnnotationURLCitation(end_index=10621, start_index=10443, title='The genetic duet of concurrent RASAL1 and PTEN alterations promotes cancer aggressiveness by cooperatively activating the PI3K-AKT pathway - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39032134/#:~:text=clinical%20impacts%20of%20genetic%20alterations,gene%20alterations%2C%20with%20cancer%20progression')
29. AnnotationURLCitation(end_index=10781, start_index=10622, title='The genetic duet of concurrent RASAL1 and PTEN alterations promotes cancer aggressiveness by cooperatively activating the PI3K-AKT pathway - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39032134/#:~:text=activation%2C%20with%20the%20development%20of,AKT%20pathway.%20This%20represents')
30. AnnotationURLCitation(end_index=11181, start_index=11022, title='The genetic duet of concurrent RASAL1 and PTEN alterations promotes cancer aggressiveness by cooperatively activating the PI3K-AKT pathway - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39032134/#:~:text=activation%2C%20with%20the%20development%20of,AKT%20pathway.%20This%20represents')
31. AnnotationURLCitation(end_index=11423, start_index=11260, title='The genetic duet of concurrent RASAL1 and PTEN alterations promotes cancer aggressiveness by cooperatively activating the PI3K-AKT pathway - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39032134/#:~:text=cancer%2C%20this%20genetic%20trio%20was,defects%20drive%20oncogenesis%20and%20cancer')
32. AnnotationURLCitation(end_index=11973, start_index=11863, title='RASAL1 Gene - GeneCards | RASL1 Protein | RASL1 Antibody', type='url_citation', url='https://www.genecards.org/cgi-bin/carddisp.pl?gene=RASAL1#:~:text=,RASL1_HUMAN%2CO95294')
33. AnnotationURLCitation(end_index=12231, start_index=12081, title='RASAL1 Gene - GeneCards | RASL1 Protein | RASL1 Antibody', type='url_citation', url='https://www.genecards.org/cgi-bin/carddisp.pl?gene=RASAL1#:~:text=%2A%20RAS%20GTPase,thyroid%20and%20adrenal%20medulla%20RASAL1')
34. AnnotationURLCitation(end_index=12850, start_index=12679, title='RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis | Oncotarget', type='url_citation', url='https://www.oncotarget.com/article/17609/text/#:~:text=decreased%20during%20HSC%20activation%2C%20and,We%20demonstrate%20that%20RASAL1%20suppresses')
35. AnnotationURLCitation(end_index=13573, start_index=13446, title='RASAL1 [Human] | GeneGlobe', type='url_citation', url='https://geneglobe.qiagen.com/us/knowledge/gene/ENSG00000111344#:~:text=activating%20proteins,provided')
36. AnnotationURLCitation(end_index=14234, start_index=14076, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=6,2012%3B28%3A1475%E2%80%9381')
37. AnnotationURLCitation(end_index=14891, start_index=14680, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=tumours%20where%20it%20has%20been,in%20neuronal%20processes%20remains%20unexplored')
38. AnnotationURLCitation(end_index=15042, start_index=14892, title='RASAL1 Gene - GeneCards | RASL1 Protein | RASL1 Antibody', type='url_citation', url='https://www.genecards.org/cgi-bin/carddisp.pl?gene=RASAL1#:~:text=%2A%20RAS%20GTPase,thyroid%20and%20adrenal%20medulla%20RASAL1')
39. AnnotationURLCitation(end_index=15377, start_index=15224, title='Protein structure - RASAL1 - The Human Protein Atlas', type='url_citation', url='https://www.proteinatlas.org/ENSG00000111344-RASAL1/structure%2Binteraction#:~:text=expression%20cluster,i%7D%20Not%20available')
40. AnnotationURLCitation(end_index=15701, start_index=15511, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=Rasal1%20is%20a%20Ca,which%20corresponds%20to%20the%20epitope')
41. AnnotationURLCitation(end_index=16215, start_index=16013, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=We%20examined%20the%20contributions%20of,is%20shown%20to%20promote%20NMDA')
42. AnnotationURLCitation(end_index=16436, start_index=16216, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=Rasal1%20functions%20in%20two%20separate,neuronal%20development%20and%20synapse%20formation')
43. AnnotationURLCitation(end_index=16793, start_index=16594, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=molecular%20tools,synaptic%20activity%20and%20CaMKII%20phosphorylation')
44. AnnotationURLCitation(end_index=17002, start_index=16794, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=Rasal1%20translocation%20to%20the%20plasma,2%2B%7D%20in%20hippocampal%20neurons')
45. AnnotationURLCitation(end_index=17553, start_index=17327, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=neuronal%20plasma%20membrane%20in%20response,synaptic%20activity%20and%20CaMKII%20phosphorylation')
46. AnnotationURLCitation(end_index=17918, start_index=17692, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=neuronal%20plasma%20membrane%20in%20response,synaptic%20activity%20and%20CaMKII%20phosphorylation')
47. AnnotationURLCitation(end_index=18342, start_index=18125, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=several%20pathways%20involved%20in%20cell,significant%20roles%20in%20remodelling%20spine')
48. AnnotationURLCitation(end_index=18559, start_index=18343, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=PKC%2C%20tubulin%2C%20and%20CaMKII,synaptic%20activity%20and%20CaMKII%20phosphorylation')
49. AnnotationURLCitation(end_index=18989, start_index=18773, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=PKC%2C%20tubulin%2C%20and%20CaMKII,synaptic%20activity%20and%20CaMKII%20phosphorylation')
50. AnnotationURLCitation(end_index=19484, start_index=19264, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=Rasal1%20functions%20in%20two%20separate,neuronal%20development%20and%20synapse%20formation')
51. AnnotationURLCitation(end_index=19822, start_index=19712, title='RASAL1 Gene - GeneCards | RASL1 Protein | RASL1 Antibody', type='url_citation', url='https://www.genecards.org/cgi-bin/carddisp.pl?gene=RASAL1#:~:text=,RASL1_HUMAN%2CO95294')
52. AnnotationURLCitation(end_index=20184, start_index=20016, title='Rac1 mediates dendrite formation in response to melanocyte stimulating hormone and ultraviolet light in a murine melanoma model - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/9699725/#:~:text=Dendrite%20formation%20requires%20actin%20polymerization,mutants%20of%20cdc42%20and%20rhoA')
53. AnnotationURLCitation(end_index=20333, start_index=20185, title='Rac1 mediates dendrite formation in response to melanocyte stimulating hormone and ultraviolet light in a murine melanoma model - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/9699725/#:~:text=this%20paper%20we%20show%20that,rac1%20is%20an%20important%20signaling')
54. AnnotationURLCitation(end_index=21122, start_index=20969, title='Identification of a Ras GTPase-activating protein regulated by receptor-mediated Ca2+ oscillations - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC394250/#:~:text=Many%20receptor%20tyrosine%20kinases%20and,Bootman%20et%20al%2C%202001')
55. AnnotationURLCitation(end_index=21306, start_index=21123, title='Identification of a Ras GTPase-activating protein regulated by receptor-mediated Ca2+ oscillations - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC394250/#:~:text=Many%20receptor%20tyrosine%20kinases%20and,such%20as%20fertilisation%2C%20secretion%2C%20contraction')
56. AnnotationURLCitation(end_index=21982, start_index=21816, title='Identification of a Ras GTPase-activating protein regulated by receptor-mediated Ca2+ oscillations - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC394250/#:~:text=induction%20of%20selective%20cellular%20functions,and%20the%20regulation%20of%20Ras')
57. AnnotationURLCitation(end_index=22108, start_index=21983, title='Identification of a Ras GTPase-activating protein regulated by receptor-mediated Ca2+ oscillations - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC394250/#:~:text=duration%20of%20the%20Ca,2%2B%7D%20signals')
58. AnnotationURLCitation(end_index=22952, start_index=22857, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=Conclusions')
59. AnnotationURLCitation(end_index=23090, start_index=22953, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=the%20active%20GTP,to%20help%20further%20refine%20the')
60. AnnotationURLCitation(end_index=23457, start_index=23331, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=Among%2013%20negative%20modulators%20of,of')
61. AnnotationURLCitation(end_index=23656, start_index=23458, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=and%20thyroid%20tumor%E2%80%93suppressing%20activities%2C%20which,pathways%2C%20revealing%20a%20largely%20mutually')
62. AnnotationURLCitation(end_index=24008, start_index=23882, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=Among%2013%20negative%20modulators%20of,of')
63. AnnotationURLCitation(end_index=24168, start_index=24009, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=which%20was%20coupled%20to%20its,of%20tumors%20carrying%20RASAL1%20mutation')
64. AnnotationURLCitation(end_index=24510, start_index=24339, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=collectively%20found%20in%20zero%20of,a%20largely%20mutually%20exclusive%20relationship')
65. AnnotationURLCitation(end_index=24800, start_index=24665, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=the%20active%20GTP,in%20the%20context%20of%20recent')
66. AnnotationURLCitation(end_index=24972, start_index=24801, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=collectively%20found%20in%20zero%20of,a%20largely%20mutually%20exclusive%20relationship')
67. AnnotationURLCitation(end_index=25209, start_index=25072, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=the%20active%20GTP,to%20help%20further%20refine%20the')
68. AnnotationURLCitation(end_index=25512, start_index=25389, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=a%20tumor%20suppressor%20gene%20in,This')
69. AnnotationURLCitation(end_index=25869, start_index=25755, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=4.88,harbored%20any%20of%20the')
70. AnnotationURLCitation(end_index=25965, start_index=25870, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=Conclusions')
71. AnnotationURLCitation(end_index=26370, start_index=26243, title='RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis | Oncotarget', type='url_citation', url='https://www.oncotarget.com/article/17609/text/#:~:text=%28GDP,as%20well%2C%20suggesting%20that%20RASAL1')
72. AnnotationURLCitation(end_index=26746, start_index=26604, title='RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis | Oncotarget', type='url_citation', url='https://www.oncotarget.com/article/17609/text/#:~:text=Ras%20protein%20activator%20like%201,to%20the%20inactive%20form')
73. AnnotationURLCitation(end_index=26905, start_index=26747, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=6,2012%3B28%3A1475%E2%80%9381')
74. AnnotationURLCitation(end_index=27232, start_index=27035, title='Rasal1 regulates calcium dependent neuronal maturation by modifying microtubule dynamics | Cell & Bioscience | Full Text', type='url_citation', url='https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-024-01193-w#:~:text=new%20mechanism%20of%20Ras%20activation,2007%3B104%3A12353%E2%80%938')
75. AnnotationURLCitation(end_index=27786, start_index=27608, title='The genetic duet of concurrent RASAL1 and PTEN alterations promotes cancer aggressiveness by cooperatively activating the PI3K-AKT pathway - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39032134/#:~:text=clinical%20impacts%20of%20genetic%20alterations,gene%20alterations%2C%20with%20cancer%20progression')
76. AnnotationURLCitation(end_index=27898, start_index=27787, title='The genetic duet of concurrent RASAL1 and PTEN alterations promotes cancer aggressiveness by cooperatively activating the PI3K-AKT pathway - PubMed', type='url_citation', url='https://pubmed.ncbi.nlm.nih.gov/39032134/#:~:text=in%209924%20cancers%20of%2033,CI')
77. AnnotationURLCitation(end_index=28528, start_index=28361, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=methylated%20and%20silenced%20in%20thyroid,genetic%20alterations%20can%20occur%20in')
78. AnnotationURLCitation(end_index=28876, start_index=28709, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=methylated%20and%20silenced%20in%20thyroid,genetic%20alterations%20can%20occur%20in')
79. AnnotationURLCitation(end_index=29266, start_index=29131, title='RASAL1 in Thyroid Cancer: Promise From a New Friend - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4184083/#:~:text=the%20active%20GTP,in%20the%20context%20of%20recent')
80. AnnotationURLCitation(end_index=29443, start_index=29267, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=include%20RAF%E2%86%92%20MEK%20%E2%86%92%20ERK,PI3K%20pathway%2C%20genetic%20or%20epigenetic')
81. AnnotationURLCitation(end_index=30160, start_index=29962, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=and%20thyroid%20tumor%E2%80%93suppressing%20activities%2C%20which,pathways%2C%20revealing%20a%20largely%20mutually')
82. AnnotationURLCitation(end_index=30985, start_index=30810, title='Methylation determines fibroblast activation and fibrogenesis in the kidney - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3106179/#:~:text=molecular%20mechanisms%2C%20we%20hypothesized%20that,and%20fibrogenesis%20in%20the%20kidney')
83. AnnotationURLCitation(end_index=31165, start_index=30986, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=Epigenetic%20modifications%20can%20cause%20the,fibroblast%20activation%20is%20associated%20with')
84. AnnotationURLCitation(end_index=31588, start_index=31413, title='Methylation determines fibroblast activation and fibrogenesis in the kidney - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3106179/#:~:text=molecular%20mechanisms%2C%20we%20hypothesized%20that,and%20fibrogenesis%20in%20the%20kidney')
85. AnnotationURLCitation(end_index=31768, start_index=31589, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=Epigenetic%20modifications%20can%20cause%20the,fibroblast%20activation%20is%20associated%20with')
86. AnnotationURLCitation(end_index=32167, start_index=31996, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=studies%20have%20showed%20a%20prominent,due%20to%20RASAL1%20promoter%20hypermethylation')
87. AnnotationURLCitation(end_index=32522, start_index=32376, title='Methylation determines fibroblast activation and fibrogenesis in the kidney - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3106179/#:~:text=To%20test%20our%20hypothesis%20that,1d%2Cf%29%20and%20type%20I')
88. AnnotationURLCitation(end_index=32698, start_index=32523, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=In%20their%20article%20published%20in,subsequent%20replacement%20with%20unmethylated%20CpGs')
89. AnnotationURLCitation(end_index=33120, start_index=32974, title='Methylation determines fibroblast activation and fibrogenesis in the kidney - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3106179/#:~:text=To%20test%20our%20hypothesis%20that,1d%2Cf%29%20and%20type%20I')
90. AnnotationURLCitation(end_index=33508, start_index=33333, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=In%20their%20article%20published%20in,subsequent%20replacement%20with%20unmethylated%20CpGs')
91. AnnotationURLCitation(end_index=33694, start_index=33509, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=is%20associated%20with%20ameliorating%20effects,subsequent%20replacement%20with%20unmethylated%20CpGs')
92. AnnotationURLCitation(end_index=34174, start_index=34001, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=The%20results%20add%20new%20information,fibroblast%20activation%20and%20fibrogenesis%20in')
93. AnnotationURLCitation(end_index=34591, start_index=34401, title='RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis | Oncotarget', type='url_citation', url='https://www.oncotarget.com/article/17609/text/#:~:text=experimental%20renal%20fibrosis%20models%20identified,fibroblasts%20increased%20the%20intrinsic%20proliferative')
94. AnnotationURLCitation(end_index=34701, start_index=34592, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=%28Bechtel%20et%20al,2014')
95. AnnotationURLCitation(end_index=34989, start_index=34869, title='RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis | Oncotarget', type='url_citation', url='https://www.oncotarget.com/article/17609/text/#:~:text=match%20at%20L139%20increases%20global,15')
96. AnnotationURLCitation(end_index=35099, start_index=34990, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=%28Bechtel%20et%20al,2014')
97. AnnotationURLCitation(end_index=35508, start_index=35349, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=of%20the%20Ras%20protein%2C%20is,hypermethylation%20can%20be%20induced%20by')
98. AnnotationURLCitation(end_index=36014, start_index=35839, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=In%20their%20article%20published%20in,subsequent%20replacement%20with%20unmethylated%20CpGs')
99. AnnotationURLCitation(end_index=36188, start_index=36015, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=The%20results%20add%20new%20information,fibroblast%20activation%20and%20fibrogenesis%20in')
100. AnnotationURLCitation(end_index=36556, start_index=36425, title='Hypermethylated RASAL1’s promotive role in chemoresistance and tumorigenesis of choriocarcinoma was regulated by TET2 but not DNMTs - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC11312928/#:~:text=Skip%20to%20main%20content%20BMC,1%7D%2C%20Han')
101. AnnotationURLCitation(end_index=36864, start_index=36733, title='Hypermethylated RASAL1’s promotive role in chemoresistance and tumorigenesis of choriocarcinoma was regulated by TET2 but not DNMTs - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC11312928/#:~:text=Skip%20to%20main%20content%20BMC,1%7D%2C%20Han')
102. AnnotationURLCitation(end_index=37297, start_index=37167, title='Hypoxia-Induced Changes in DNA Methylation Alter RASAL1 and TGFβ1 Expression in Human Trabecular Meshwork Cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4849706/#:~:text=Hypoxia,role%20in%20mediating%20fibrosis%20and')
103. AnnotationURLCitation(end_index=37428, start_index=37298, title='Hypoxia-Induced Changes in DNA Methylation Alter RASAL1 and TGFβ1 Expression in Human Trabecular Meshwork Cells - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4849706/#:~:text=Hypoxia,Absorbance%20450nm%29%2C%20and%20found')
104. AnnotationURLCitation(end_index=38872, start_index=38763, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=%28Bechtel%20et%20al,2014')
105. AnnotationURLCitation(end_index=39048, start_index=38873, title='Hypermethylation of RASAL1: A Key for Renal Fibrosis - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC4484502/#:~:text=In%20their%20article%20published%20in,subsequent%20replacement%20with%20unmethylated%20CpGs')
106. AnnotationURLCitation(end_index=39917, start_index=39741, title='Identification of RASAL1 as a Major Tumor Suppressor Gene in Thyroid Cancer - PMC', type='url_citation', url='https://pmc.ncbi.nlm.nih.gov/articles/PMC3818169/#:~:text=include%20RAF%E2%86%92%20MEK%20%E2%86%92%20ERK,PI3K%20pathway%2C%20genetic%20or%20epigenetic')