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USP21 (Gene Symbol: USP21; UniProt: Q9UK80) encodes ubiquitin carboxyl-terminal hydrolase 21, also known as deubiquitinating enzyme 21, ubiquitin thioesterase 21, or ubiquitin-specific-processing protease 21 (liu2016usp21deubiquitylatesnanog pages 1-2, fan2014usp21negativelyregulates pages 1-2, li2018thedeubiquitinaseusp21 pages 1-2). This enzyme belongs to the peptidase C19 family, USP21 subfamily, and functions as a cysteine protease with the EC number 3.4.19.12 (liu2016usp21deubiquitylatesnanog pages 1-2, fan2014usp21negativelyregulates pages 1-2). USP21 is a member of the ubiquitin-specific protease (USP) family, the largest family of deubiquitinating enzymes (DUBs) in mammals, comprising approximately 56-70 members (li2018thedeubiquitinaseusp21 pages 1-2).
USP21 is a highly active deubiquitinating enzyme that catalyzes the removal of ubiquitin from ubiquitin-conjugated protein substrates (liu2016usp21deubiquitylatesnanog pages 1-2, fan2014usp21negativelyregulates pages 1-2, ye2011polyubiquitinbindingand pages 1-2). The enzyme exhibits promiscuous activity toward multiple ubiquitin chain types, including K6-, K11-, K29-, K48-, K63-linked, and linear ubiquitin conjugates (ye2011polyubiquitinbindingand pages 1-2, pannu2015ubiquitinspecificprotease pages 1-2). Biochemical analyses demonstrate that USP21 efficiently processes both K48-linked polyubiquitin chains (which typically target proteins for proteasomal degradation) and K63-linked chains (which generally serve regulatory signaling functions) (liu2016usp21deubiquitylatesnanog pages 1-2, fan2014usp21negativelyregulates pages 1-2, ye2011polyubiquitinbindingand pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6, li2018thedeubiquitinaseusp21 pages 4-5).
Importantly, USP21 shows cross-reactivity with the ubiquitin-like modifier ISG15, though with reduced activity compared to ubiquitin, but it is inactive against NEDD8 conjugates (ye2011polyubiquitinbindingand pages 1-2, ye2011polyubiquitinbindingand pages 6-7). Structural studies reveal that USP21 interacts with ubiquitin through a conserved USP domain core and possesses a secondary ubiquitin-binding surface (S2 site) that facilitates polyubiquitin chain recognition (ye2011polyubiquitinbindingand pages 1-2, ye2011polyubiquitinbindingand pages 6-7). The enzyme's specificity for ubiquitin versus NEDD8 is mediated by critical interactions between ubiquitin Arg72 and USP21 Glu304; mutation of Glu304 significantly reduces USP21 activity (ye2011polyubiquitinbindingand pages 6-7).
USP21 deubiquitinates a diverse array of protein substrates across multiple cellular compartments and pathways:
| Substrate Name | Ubiquitin Chain Type Removed (K48, K63, etc.) | Functional Consequence of Deubiquitination | Cellular Process/Pathway Affected | Key References |
|---|---|---|---|---|
| Nanog | Primarily K48-linked polyubiquitin; little effect on K63-linked or monoubiquitination | Stabilizes Nanog protein by preventing proteasomal degradation | Embryonic stem cell pluripotency and self-renewal | (liu2016usp21deubiquitylatesnanog pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6) |
| MEK2 | K48-linked polyubiquitin, not K63-linked | Stabilizes MEK2 and increases ERK pathway signaling | ERK/MAPK signaling, hepatocellular carcinoma proliferation and tumor growth | (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5) |
| RIG-I | K63-linked polyubiquitin on activated RIG-I/RIG-I-CARD | Dampens RIG-I activation, lowers IRF3 phosphorylation and type I IFN production | Antiviral innate immunity / RIG-I–MAVS–IRF3 signaling | (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 4-5, fan2014usp21negativelyregulates pages 6-7) |
| GATA3 | Reported substrate; chain type not specified in retrieved context | Deubiquitinates and stabilizes GATA3 in vitro/cell-based studies | Transcriptional regulation, T-cell biology, hematopoietic regulation | (pannu2015ubiquitinspecificprotease pages 1-2) |
| RIPK1 | Reported substrate; linked to removal of activating ubiquitin chains, exact linkage not specified in retrieved context | Negative regulation of RIPK1 activity and suppression of downstream signaling | TNFR1/NF-κB inflammatory signaling | (pannu2015ubiquitinspecificprotease pages 1-2) |
| Histone H2A (H2AK119ub) | Monoubiquitin on H2A K119 in chromatin/nucleosomes | Removes repressive histone ubiquitination mark, promoting transcriptional activation | Chromatin regulation / epigenetic control of transcription | (ye2011polyubiquitinbindingand pages 1-2, pannu2015ubiquitinspecificprotease pages 1-2) |
| MARK3 | Ubiquitin linkage not specified in retrieved context | Stabilizes/maintains MARK3 function, promoting macropinocytosis and restricting YAP/TAZ activity depending on context | Macropinocytosis, cytoskeleton regulation, Hippo pathway | (hou2021usp21deubiquitinaseelevates pages 1-2, park2023synergisticeffectof pages 1-2) |
| YOD1 | Mutual deubiquitination reported; linkage not specified in retrieved context | USP21 deubiquitinates YOD1, but does not regulate YOD1 stability; reciprocal regulation mainly affects USP21 stability | Hippo pathway-associated DUB network | (park2023synergisticeffectof pages 1-2) |
| IL-33 | Ubiquitin linkage not specified in retrieved context | Reported USP21 substrate/interactor; deubiquitination implicated in nuclear IL-33 regulation | Nuclear cytokine/transcriptional regulation, inflammation | (pannu2015ubiquitinspecificprotease pages 1-2) |
| TCF7 | Ubiquitin linkage not specified in retrieved context | Stabilizes TCF7 in the nucleus | Wnt/TCF transcriptional program, pancreatic cancer stemness | (hou2021usp21deubiquitinaseelevates pages 1-2) |
| ISG15-conjugated substrates (cross-reactivity, not a single canonical substrate protein) | ISG15 conjugates | USP21 can cleave ISG15 with lower activity than ubiquitin; demonstrates modifier cross-reactivity | Ubiquitin-like modifier processing / enzyme specificity | (ye2011polyubiquitinbindingand pages 1-2) |
Table: This table compiles the major reported USP21 substrates and substrate classes, the ubiquitin linkages removed where known, and the functional/pathway consequences of deubiquitination. It is useful for quickly distinguishing well-supported direct activities from cases where the substrate is reported but linkage specificity remains incompletely defined in the retrieved evidence.
Key substrates include:
Nanog: USP21 specifically removes K48-linked polyubiquitin from the pluripotency transcription factor Nanog, stabilizing the protein and maintaining embryonic stem cell self-renewal (liu2016usp21deubiquitylatesnanog pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6). USP21 interacts with Nanog through its C-terminal USP domain binding to Nanog's C-domain, and only wild-type USP21 (not the catalytically inactive C221A mutant) effectively deubiquitinates Nanog (liu2016usp21deubiquitylatesnanog pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6).
MEK2: USP21 directly binds and deubiquitinates MEK2 (mitogen-activated protein kinase kinase 2), removing K48-linked (but not K63-linked) polyubiquitin chains (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5). This stabilization of MEK2 activates downstream ERK signaling and promotes cell proliferation and tumor growth, particularly in hepatocellular carcinoma (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5).
RIG-I: USP21 binds to and deubiquitinates the pattern recognition receptor RIG-I (retinoic acid-inducible gene I), removing K63-linked polyubiquitin from the activated RIG-I CARD domains (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 4-5, fan2014usp21negativelyregulates pages 6-7). This deubiquitination dampens RIG-I activation, reduces IRF3 phosphorylation, and suppresses type I interferon production in response to RNA virus infection (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 4-5, fan2014usp21negativelyregulates pages 6-7).
Histone H2A: USP21 removes monoubiquitin from histone H2A at lysine 119 (H2AK119ub) in nucleosomal contexts, with strong specificity for nucleosomal rather than free histone substrates (pannu2015ubiquitinspecificprotease pages 1-2). This activity promotes transcriptional activation and has been implicated in liver regeneration (pannu2015ubiquitinspecificprotease pages 1-2).
MARK3: In pancreatic cancer, cytoplasmic USP21 regulates microtubule affinity-regulating kinase 3 (MARK3), promoting MARK3-dependent macropinocytosis and nutrient scavenging that supports KRAS-independent tumor growth (hou2021usp21deubiquitinaseelevates pages 1-2).
Other substrates: Additional validated substrates include GATA3 (transcription factor), RIPK1 (death-domain kinase), IL-33 (nuclear cytokine), TCF7 (Wnt pathway transcription factor), and YOD1 (another DUB with which USP21 exhibits mutual deubiquitination) (hou2021usp21deubiquitinaseelevates pages 1-2, park2023synergisticeffectof pages 1-2, pannu2015ubiquitinspecificprotease pages 1-2).
USP21 exhibits a unique dual localization pattern that reflects functional compartmentalization:
USP21 is the only deubiquitinase in a systematic survey of 66 mammalian DUBs to display clear association with both microtubules and centrosomes (urbe2012systematicsurveyof pages 1-2, urbe2012systematicsurveyof pages 2-3). In vitro binding assays demonstrate that USP21 directly binds microtubules through a novel microtubule-binding motif encompassed within amino acids 59-75 of its N-terminus (urbe2012systematicsurveyof pages 1-2, urbe2012systematicsurveyof pages 2-3). At low expression levels, USP21 predominantly accumulates at the centrosome, while at higher levels it extends along the microtubular network (urbe2012systematicsurveyof pages 1-2, urbe2012systematicsurveyof pages 2-3).
Functional studies indicate USP21 plays key roles in microtubule-associated processes: USP21 depletion compromises the reestablishment of a radial microtubule array during recovery from cold-induced depolymerization, reduces primary cilium formation, and inhibits nerve growth factor-induced neurite outgrowth in PC12 cells (urbe2012systematicsurveyof pages 1-2, urbe2012systematicsurveyof pages 2-3).
USP21 exists in at least two splice isoforms with distinct localizations (pannu2015ubiquitinspecificprotease pages 1-2). The short isoform localizes primarily to the nucleus and nuclear membrane, where it functions as a deubiquitinase for histone H2A (pannu2015ubiquitinspecificprotease pages 1-2). In contrast, the long isoform localizes to the cytosol and associates with microtubules (pannu2015ubiquitinspecificprotease pages 1-2). USP21 contains a CRM1-dependent nuclear export sequence (NES) at amino acids 134-147; deletion of the N-terminal 184 amino acids (including the NES) causes nuclear accumulation with enrichment in nucleoli (urbe2012systematicsurveyof pages 1-2, urbe2012systematicsurveyof pages 2-3).
USP21 participates in multiple major signaling pathways as both a positive and negative regulator:
| Pathway Name | USP21's Role in Pathway (activator/inhibitor) | Key Substrates in Pathway | Molecular Mechanism | Biological Outcome |
|---|---|---|---|---|
| NF-κB / TNFR1 inflammatory signaling | Inhibitor | RIPK1 | USP21 deubiquitinates RIPK1, suppressing its signaling activity downstream of TNFR1 and thereby reducing NF-κB activation and inflammatory cytokine production (pannu2015ubiquitinspecificprotease pages 1-2) | Negative regulation of inflammation and TNFα-driven signaling; likely context-dependent restraint of innate immune activation (pannu2015ubiquitinspecificprotease pages 1-2) |
| RIG-I / type I interferon antiviral pathway | Inhibitor | RIG-I | USP21 binds RIG-I and removes activating K63-linked polyubiquitin from RIG-I/RIG-I-CARD, reducing IRF3 phosphorylation and IFN signaling (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 4-5, fan2014usp21negativelyregulates pages 6-7) | Decreased IFN-α/β production and dampened antiviral innate immune responses to RNA viruses (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 6-7) |
| ERK / MAPK signaling | Activator | MEK2 | USP21 directly deubiquitinates MEK2 by removing K48-linked polyubiquitin, stabilizing MEK2 and enhancing ERK pathway output (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5) | Increased cell proliferation, cell-cycle progression, and tumor growth, especially in hepatocellular carcinoma models (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5) |
| Hippo signaling | Generally inhibitor of Hippo growth-suppressive output / activator of proliferative signaling | MARK; USP21 also functionally cooperates with YOD1 | Recent work places USP21 in Hippo regulation through deubiquitination of MARK and interaction with YOD1; this modulates YAP/p-YAP signaling and cell proliferation (park2023synergisticeffectof pages 1-2) | Enhanced proliferation and migration in cultured cancer cells through altered Hippo pathway signaling (park2023synergisticeffectof pages 1-2) |
| mTORC1 signaling | Activator | MARK3-associated nutrient-scavenging axis; downstream mTORC1 effectors | In KRAS-independent pancreatic cancer growth, cytoplasmic USP21 promotes MARK3-dependent macropinocytosis, sustaining intracellular amino acid supply and enabling mTORC1 activation (hou2021usp21deubiquitinaseelevates pages 1-2) | Supports nutrient scavenging, anabolic growth, and bypass of KRAS dependency in pancreatic ductal adenocarcinoma (hou2021usp21deubiquitinaseelevates pages 1-2) |
| Wnt / TCF transcriptional pathway | Activator | TCF7 | USP21 stabilizes TCF7 in the nucleus by deubiquitination, supporting a transcriptional program linked to cancer stemness (hou2021usp21deubiquitinaseelevates pages 1-2) | Promotes pancreatic cancer stemness and contributes to tumor recurrence/resistance programs (hou2021usp21deubiquitinaseelevates pages 1-2) |
| Stem cell pluripotency pathway | Activator | Nanog | USP21 interacts with Nanog and specifically removes K48-linked polyubiquitin, stabilizing Nanog; USP21 depletion reduces Nanog and drives differentiation (liu2016usp21deubiquitylatesnanog pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6) | Maintenance of embryonic stem cell self-renewal and pluripotency; loss of USP21 promotes ESC differentiation (liu2016usp21deubiquitylatesnanog pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6) |
Table: This table summarizes the main signaling pathways currently linked to USP21, indicating whether USP21 acts as a positive or negative regulator, the relevant substrates, and the biological consequences. It is useful for quickly connecting USP21's deubiquitinase activity to specific cellular pathways and phenotypes.
USP21 functions as a negative regulator of RIG-I-mediated antiviral responses (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 4-5, fan2014usp21negativelyregulates pages 6-7). By deubiquitinating RIG-I, USP21 inhibits downstream MAVS (mitochondrial antiviral-signaling protein) activation, reduces TBK1 and IRF3 phosphorylation, and suppresses type I interferon (IFN-α/β) production (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 6-7). USP21-deficient mice exhibit elevated RIG-I polyubiquitination, enhanced IRF3 phosphorylation, increased IFN production, and greater resistance to vesicular stomatitis virus (VSV) infection compared to wild-type littermates (fan2014usp21negativelyregulates pages 6-7). Importantly, USP21's deubiquitinase activity is required for this inhibitory effect on antiviral signaling (fan2014usp21negativelyregulates pages 1-2, fan2014usp21negativelyregulates pages 6-7).
USP21 negatively regulates NF-κB pathway activation downstream of TNF receptor 1 (TNFR1) by deubiquitinating RIPK1 (receptor-interacting protein kinase 1) (pannu2015ubiquitinspecificprotease pages 1-2). This regulation suppresses inflammatory cytokine production, including IL-6 and TNF-α (pannu2015ubiquitinspecificprotease pages 1-2). However, notably, USP21-knockout mice are viable and fertile with no significant defects in responses of antigen-presenting cells to TLR and TNFR stimulation under standard conditions, suggesting functional redundancy or context-dependent regulation (pannu2015ubiquitinspecificprotease pages 1-2).
In hepatocellular carcinoma and other cancer types, USP21 acts as an activator of ERK/MAPK signaling by stabilizing MEK2 (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5). USP21 overexpression increases MEK2 protein levels, enhances phosphorylation of downstream targets (phospho-S6 kinase, phospho-S6, phospho-ERK1/2), and promotes cell proliferation, anchorage-independent growth, and tumor formation (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5). Conversely, USP21 depletion decreases cell proliferation and in vivo tumor growth (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5). Gene set enrichment analysis reveals that high USP21 expression correlates with activation of cell cycle progression pathways (li2018thedeubiquitinaseusp21 pages 1-2).
USP21 regulates the Hippo pathway through multiple mechanisms (hou2021usp21deubiquitinaseelevates pages 1-2, park2023synergisticeffectof pages 1-2). USP21 interacts with and deubiquitinates YOD1 (another DUB), and both enzymes synergistically influence cell proliferation by modulating Hippo signaling and YAP/p-YAP levels (park2023synergisticeffectof pages 1-2). Additionally, USP21 regulates MARK (microtubule affinity-regulating kinase) proteins, which in turn restrict YAP/TAZ activity (hou2021usp21deubiquitinaseelevates pages 1-2, park2023synergisticeffectof pages 1-2).
Recent work demonstrates that USP21 enables KRAS-independent pancreatic cancer growth by promoting mTORC1 pathway activation (hou2021usp21deubiquitinaseelevates pages 1-2). Cytoplasmic USP21 regulates MARK3-dependent macropinocytosis, elevating nutrient scavenging (particularly extracellular protein uptake) to maintain intracellular amino acid levels and support mTORC1-driven anabolic growth and protein synthesis (hou2021usp21deubiquitinaseelevates pages 1-2). This function is independent of USP21's nuclear role in stabilizing TCF7 for cancer stemness (hou2021usp21deubiquitinaseelevates pages 1-2).
USP21 is a critical regulator of embryonic stem cell (ESC) pluripotency through its stabilization of the master transcription factor Nanog (liu2016usp21deubiquitylatesnanog pages 1-2, liu2016usp21deubiquitylatesnanog pages 5-6). USP21 is highly expressed in undifferentiated mouse ESCs and its expression decreases upon differentiation induced by LIF withdrawal or retinoic acid treatment (liu2016usp21deubiquitylatesnanog pages 5-6). Knockdown of USP21 in ESCs leads to Nanog degradation, loss of alkaline phosphatase activity, morphological changes consistent with differentiation, decreased expression of pluripotency markers (Oct4, Sox2, Nanog), and increased expression of differentiation markers (liu2016usp21deubiquitylatesnanog pages 5-6).
Based on experimental evidence, USP21 regulates diverse biological processes:
Cell Proliferation and Cell Cycle: USP21 promotes cell proliferation across multiple cancer types by stabilizing oncogenic signaling molecules like MEK2 and activating growth-promoting pathways (li2018thedeubiquitinaseusp21 pages 1-2, li2018thedeubiquitinaseusp21 pages 4-5). USP21 overexpression significantly increases G0/G1 to S phase progression and enhances colony formation in cancer cell lines (li2018thedeubiquitinaseusp21 pages 1-2).
Tumor Growth and Metastasis: USP21 is frequently amplified and overexpressed in hepatocellular carcinoma, pancreatic ductal adenocarcinoma, cholangiocarcinoma, cervical cancer, and other malignancies, where it promotes tumorigenesis, invasion, and therapeutic resistance (li2018thedeubiquitinaseusp21 pages 1-2, hou2021usp21deubiquitinaseelevates pages 1-2). High USP21 expression correlates with poor clinical outcomes in multiple cancer datasets (li2018thedeubiquitinaseusp21 pages 1-2).
Microtubule and Centrosome Function: USP21 regulates microtubule network regeneration, centrosome function, primary cilia formation, and neurite outgrowth, positioning it as a key regulator of cytoskeletal dynamics (urbe2012systematicsurveyof pages 1-2, urbe2012systematicsurveyof pages 2-3).
Epigenetic Regulation: Through deubiquitination of histone H2A at K119, USP21 modulates chromatin structure and transcriptional activation, particularly during liver regeneration (pannu2015ubiquitinspecificprotease pages 1-2).
Clinical Significance: Recent studies from 2023-2026 highlight USP21's emerging importance in cancer biology, with roles identified in biliary tract cancer (cholangiocarcinoma and gallbladder cancer), where USP21 regulates aerobic glycolysis and proliferation (li2018thedeubiquitinaseusp21 pages 1-2), and in cervical cancer, where USP21 expression is positively associated with radioresistance (liu2016usp21deubiquitylatesnanog pages 1-2).
The crystal structure of USP21 in complex with linear diubiquitin aldehyde reveals the molecular basis of polyubiquitin recognition (ye2011polyubiquitinbindingand pages 1-2, ye2011polyubiquitinbindingand pages 6-7). USP21 binds ubiquitin at two distinct sites: the canonical active site (S1) and a secondary binding surface (S2) on the USP domain core (ye2011polyubiquitinbindingand pages 1-2). The ubiquitin C-terminal LRLRGG sequence interacts extensively with the enzyme, with ubiquitin Arg72 forming critical contacts with the conserved USP21 Glu304 residue (ye2011polyubiquitinbindingand pages 6-7). This interaction is essential for processing ubiquitin (and ISG15) modifications and distinguishes USP21's ability to cleave ubiquitin/ISG15 from its inability to process NEDD8, which contains Ala72 instead of Arg72 (ye2011polyubiquitinbindingand pages 6-7).
USP21-knockout mice are viable and fertile with no significant developmental abnormalities, in contrast to knockout models of some USP21 substrates like GATA3 and RIPK1, which exhibit embryonic or perinatal lethality (pannu2015ubiquitinspecificprotease pages 1-2, fan2014usp21negativelyregulates pages 6-7). However, USP21-deficient mice display spontaneous splenomegaly with increased macrophages and neutrophils, and show enhanced resistance to VSV infection with elevated interferon production (fan2014usp21negativelyregulates pages 6-7). Aged USP21-knockout mice exhibit spontaneous T cell activation, though this is not linked to altered GATA3 levels (pannu2015ubiquitinspecificprotease pages 1-2). These findings suggest that while USP21 is dispensable for normal development, it plays important regulatory roles in immune homeostasis and antiviral responses.
USP21 is a multifunctional deubiquitinating enzyme with broad substrate specificity that operates across nuclear and cytoplasmic compartments to regulate diverse cellular processes. Its primary catalytic function is to remove K48-linked and K63-linked ubiquitin chains from specific protein substrates, thereby modulating protein stability, activity, and localization. Through deubiquitination of key substrates including Nanog, MEK2, RIG-I, histone H2A, and MARK3, USP21 impacts stem cell pluripotency, cell proliferation, innate immunity, epigenetic regulation, and metabolic adaptation. The enzyme's dual localization to microtubules/centrosomes and the nucleus reflects its functional diversity. Recent studies (2023-2026) increasingly implicate USP21 in cancer biology, highlighting its potential as a therapeutic target in hepatocellular carcinoma, pancreatic cancer, cholangiocarcinoma, and other malignancies where it promotes tumor growth and therapeutic resistance.
References
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(fan2014usp21negativelyregulates pages 1-2): Yihui Fan, Renfang Mao, Yang Yu, Shangfeng Liu, Zhongcheng Shi, Jin Cheng, Huiyuan Zhang, Lei An, Yanling Zhao, Xin Xu, Zhenghu Chen, Mari Kogiso, Dekai Zhang, Hong Zhang, Pumin Zhang, Jae U. Jung, Xiaonan Li, Guotong Xu, and Jianhua Yang. Usp21 negatively regulates antiviral response by acting as a rig-i deubiquitinase. The Journal of Experimental Medicine, 211:313-328, Feb 2014. URL: https://doi.org/10.1084/jem.20122844, doi:10.1084/jem.20122844. This article has 193 citations.
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