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this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.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.
The target gene/protein is Jak1 / tyrosine-protein kinase JAK1 (a cytosolic non-receptor tyrosine kinase) in Mus musculus (mouse), consistent with the canonical Janus kinase family member that mediates signaling downstream of many cytokine receptors. (wei2024januskinasesand pages 1-3)
Recent structural biology reviews explicitly analyze full-length mouse JAK1 (mJAK1) and its receptor-binding and regulatory states, supporting that the sources used here align with the mouse Jak1 target rather than an ambiguous symbol from another organism. (lv2024thejakstatpathway pages 12-15)
| Aspect | Summary | Citations | Source URL + publication date |
|---|---|---|---|
| Identity verification | Target matches mouse Jak1/JAK1: a non-receptor tyrosine-protein kinase in the JAK family. The reviewed structural paper specifically discusses full-length mouse JAK1 (mJAK1), aligning with UniProt P52332 and the Mus musculus target context. JAK1 is broadly expressed and is a core mediator of cytokine signaling. | (wei2024januskinasesand pages 1-3, lv2024thejakstatpathway pages 12-15) | https://doi.org/10.53941/ijddp.2024.100007 (2024-06-05); https://doi.org/10.1038/s41392-024-01934-w (2024-08) |
| Domain architecture | JAK1 contains the canonical JAK homology regions organized into an N-terminal FERM-SH2 holodomain for receptor binding, a pseudokinase domain (JH2/PK) with regulatory/autoinhibitory function, and a C-terminal tyrosine kinase domain (JH1/TK) that catalyzes phosphorylation. Structural work shows JAK1 FERM-SH2 recognizes receptor box1/box2 motifs. | (wei2024januskinasesand pages 1-3, taylor2024differentialpropertiesof pages 2-4, lv2024thejakstatpathway pages 12-15, lv2024thejakstatpathway media faa97556) | https://doi.org/10.53941/ijddp.2024.100007 (2024-06-05); https://doi.org/10.1093/rheumatology/kead448 (2024-08); https://doi.org/10.1038/s41392-024-01934-w (2024-08) |
| Primary biochemical function | JAK1’s primary molecular role is protein tyrosine kinase activity downstream of cytokine receptors: after ligand-induced receptor complexing, JAK1 undergoes activation/transphosphorylation, phosphorylates receptor cytoplasmic tyrosines, then phosphorylates STAT transcription factors that dock via SH2 interactions. Thus its direct substrate classes are receptor tails and STATs. | (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 5-7, sarapultsev2023jakstatsignalingin pages 4-5) | https://doi.org/10.53941/ijddp.2024.100007 (2024-06-05); https://doi.org/10.1186/s43556-023-00151-1 (2023-11) |
| Key cytokine receptors and pathways | JAK1 is used by many cytokine receptor systems, including type I and type II interferon receptors, gp130/IL-6 family receptors, common gamma-chain cytokines (e.g., IL-2/IL-4/IL-7/IL-9/IL-15/IL-21, often with JAK3), and IL-10 family receptors. JAK1 pairs with JAK2, JAK3, or TYK2 depending on receptor context and propagates canonical JAK-STAT plus associated PI3K/AKT and MAPK/ERK outputs. | (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 5-7, sarapultsev2023jakstatsignalingin pages 4-5, paolino2025serumlipidsalterations pages 2-4) | https://doi.org/10.53941/ijddp.2024.100007 (2024-06-05); https://doi.org/10.1186/s43556-023-00151-1 (2023-11); https://doi.org/10.3390/medicina61010054 (2025-01) |
| Cellular localization | JAK1 is primarily cytosolic but constitutively receptor-associated at the inner face of the plasma membrane through its FERM-SH2 module binding cytokine receptor intracellular motifs. Reviews also note reported nuclear localization in some pathological or specialized contexts, suggesting noncanonical nuclear roles, though the main conserved function is membrane-proximal cytokine signaling. | (sarapultsev2023jakstatsignalingin pages 5-7, jarneborn2025thedualedgedsword pages 2-4, lv2024thejakstatpathway pages 12-15) | https://doi.org/10.1186/s43556-023-00151-1 (2023-11); https://doi.org/10.3390/pathogens14040324 (2025-03); https://doi.org/10.1038/s41392-024-01934-w (2024-08) |
| 2023-2024 developments | Major recent advances include full-length mJAK1 structural definition: cryo-EM/crystal-informed models identified distinct dimeric states including an autoinhibited state (PDB 8EWY) and active/nanobody-stabilized state (PDB 7T6F), supporting a mechanism in which cytokine-induced geometry relieves pseudokinase-mediated autoinhibition. Contemporary pharmacology reviews also emphasize that so-called JAK1 selectivity is relative, dose- and tissue-dependent, not absolute. | (taylor2024differentialpropertiesof pages 2-4, lv2024thejakstatpathway pages 12-15, lv2024thejakstatpathway media faa97556) | https://doi.org/10.1093/rheumatology/kead448 (2024-08); https://doi.org/10.1038/s41392-024-01934-w (2024-08) |
Table: This table consolidates identity verification, mechanism, pathway context, localization, and recent 2023-2024 advances for mouse Jak1/JAK1. It is useful as a compact evidence map linking each major claim to specific context IDs and source URLs.
JAKs (JAK1, JAK2, JAK3, TYK2) are intracellular tyrosine kinases that couple ligand-bound cytokine receptors to transcriptional programs via phosphorylation of receptor tails and STAT transcription factors (signal transducers and activators of transcription). (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 4-5)
Canonical pathway definition: cytokine binding promotes receptor assembly, JAK activation, receptor tyrosine phosphorylation, STAT recruitment via SH2 interactions, STAT phosphorylation, STAT dimerization, and STAT nuclear translocation to regulate gene expression. (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 4-5)
Primary enzymatic function: JAK1 catalyzes protein tyrosine phosphorylation (ATP-dependent transfer of phosphate to tyrosine residues) on (i) receptor cytoplasmic tails to create docking sites and (ii) STATs to enable their activation and transcriptional function. (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 5-7)
Thus, JAK1’s principal substrate classes in signaling are cytokine receptor intracellular tyrosines and STAT proteins. (wei2024januskinasesand pages 1-3)
JAK family proteins contain JAK-homology regions (JH1–JH7) organized into functional modules: an N-terminal receptor-binding module and a C-terminal kinase module. (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 4-5)
Key domains relevant to mouse JAK1 include:
- FERM–SH2 “holodomain”: mediates stable association with receptor intracellular motifs (“box1/box2”). (lv2024thejakstatpathway pages 12-15)
- Pseudokinase domain (JH2/PK): regulatory module that restrains basal kinase activity (autoinhibition). (wei2024januskinasesand pages 1-3, lv2024thejakstatpathway pages 12-15)
- Tyrosine kinase domain (JH1/TK): the catalytically active kinase domain, containing the ATP-binding site targeted by most JAK inhibitors. (taylor2024differentialpropertiesof pages 2-4, sarapultsev2023jakstatsignalingin pages 4-5)
JAK1 is primarily cytosolic but functions at the inner face of the plasma membrane by binding cytokine receptor intracellular regions through its FERM–SH2 module, making it effectively receptor-associated during signaling. (sarapultsev2023jakstatsignalingin pages 5-7, lv2024thejakstatpathway pages 12-15)
Noncanonical localization has been reported: JAK1 has been observed in the nucleus in certain pathological and specialized cellular contexts, suggesting possible additional functions beyond canonical membrane-proximal signaling. (sarapultsev2023jakstatsignalingin pages 5-7)
Structural work indicates the JAK1 FERM–SH2 holodomain engages receptor intracellular box1 and box2 motifs as an elongated epitope (with receptor-dependent contributions of box1 vs box2 to binding). (lv2024thejakstatpathway pages 12-15)
The pseudokinase (PK/JH2) and tyrosine kinase (TK/JH1) domains form a tandem regulatory unit in which the PK domain contributes to autoinhibition; deletion of the PK domain increases basal kinase activity but disrupts further activation, consistent with a tuned autoinhibitory/activation switch. (lv2024thejakstatpathway pages 12-15)
Recent structural analyses of full-length mJAK1 provide models for distinct dimeric states, including an autoinhibited state (PDB 8EWY) and an active/nanobody-stabilized state (PDB 7T6F), supporting the idea that cytokine-receptor geometry and JAK dimerization can relieve PK-mediated autoinhibition to enable TK activity. (lv2024thejakstatpathway pages 12-15)
Figure-level structural summary (domain map, receptor binding, and mJAK1 dimer states) is presented in Figure 7 of Lv et al. 2024. (lv2024thejakstatpathway media faa97556)
JAK1 is described as broadly expressed and participating in signaling for a wide set of cytokines, including receptors that use the common gamma chain (γc), gp130 (IL-6 family), class II cytokine receptors (e.g., interferons), and IL-10 family receptors, making it one of the most pleiotropic JAKs in cytokine biology. (wei2024januskinasesand pages 1-3)
Representative pathway pairings include JAK1 partnering with other JAKs (JAK2, JAK3, TYK2) to transmit different cytokine signals and activate different STATs, depending on receptor composition. (sarapultsev2023jakstatsignalingin pages 5-7, taylor2024differentialpropertiesof pages 2-4, sarapultsev2023jakstatsignalingin pages 4-5)
JAK-associated receptors can also engage additional downstream arms (e.g., PI3K/AKT and MAPK/ERK) alongside STAT signaling. (sarapultsev2023jakstatsignalingin pages 4-5)
Authoritative reviews emphasize that JAK–STAT signaling is controlled by multiple negative regulators, including SOCS proteins (feedback inhibitors that can promote degradation), protein tyrosine phosphatases, PIAS proteins, adaptor regulators (e.g., LNK/SH2B3), and post-translational modifications (e.g., ubiquitination, SUMOylation). (sarapultsev2023jakstatsignalingin pages 5-7)
A key 2024 development is the consolidation of full-length mJAK1 structural models that compare autoinhibited and activated conformations and connect receptor-binding geometry to relief of pseudokinase-mediated autoinhibition. (lv2024thejakstatpathway pages 12-15, lv2024thejakstatpathway media faa97556)
These structures provide a mechanistic framework for understanding how receptor engagement and JAK dimerization can switch JAK1 from restrained basal activity to signaling-competent kinase activity. (lv2024thejakstatpathway pages 12-15)
A 2024 pharmacology review stresses that JAK isoform selectivity is relative rather than absolute and is influenced by dose and tissue context, reflecting both conserved ATP-binding site architecture and cooperative JAK biology at receptors. (taylor2024differentialpropertiesof pages 2-4)
This is important for interpreting “JAK1-selective” inhibitors in vivo, where pathway effects arise from both biochemical potency and receptor/JAK pairing context. (taylor2024differentialpropertiesof pages 2-4)
Because JAK1 participates in signaling for multiple inflammatory and immune cytokines (including interferons, IL-6 family via gp130, γc cytokines with JAK3, and IL-10 family), it is a major therapeutic target for immune-mediated inflammatory diseases. (wei2024januskinasesand pages 1-3, sarapultsev2023jakstatsignalingin pages 5-7)
Clinically used JAK inhibitors typically bind the ATP site in the active kinase domain, blocking receptor/STAT phosphorylation and thus cytokine-driven transcriptional programs. (taylor2024differentialpropertiesof pages 2-4)
A 2024 review reports example biochemical potencies (IC50) against JAK1 for several approved inhibitors, including abrocitinib (29.2 nM) and ranges for filgotinib (10–53 nM), illustrating that multiple agents can have strong biochemical activity at JAK1 even if clinical selectivity differs by exposure and biology. (taylor2024differentialpropertiesof pages 2-4)
A 2024 umbrella review of 16 meta-analyses in atopic dermatitis reported that JAK inhibitors (class-level) improved:
- IGA response vs placebo: RR 2.83 (95% CI 2.25–3.56). (he2024januskinaseinhibitors pages 1-2)
- EASI75 response vs placebo: RR 2.84 (95% CI 2.2–3.67). (he2024januskinaseinhibitors pages 1-2)
- Pruritus (PP-NRS) vs placebo: SMD −0.49 (95% CI −0.67 to −0.32). (he2024januskinaseinhibitors pages 1-2)
For JAK1-selective systemic agents, the umbrella review summarized dose-related efficacy and safety signals:
- Abrocitinib: IGA response RR 3.02 (95% CI 2.26–4.02) overall; abrocitinib 200 mg improved EASI75 RR 3.04 (95% CI 2.22–4.16) vs 100 mg EASI75 RR 2.18 (95% CI 1.78–2.67). (he2024januskinaseinhibitors pages 8-11)
- Upadacitinib: EASI75 effects were reported as strong at both doses (e.g., 15 mg RR 3.48; 30 mg RR 4.14 as summarized from included meta-analyses). (he2024januskinaseinhibitors pages 8-11)
- Safety (abrocitinib 200 mg): increased risks of acne RR 4.34, headache RR 1.76, nausea RR 7.81, with a reported estimate for herpes zoster RR 1.64. (he2024januskinaseinhibitors pages 1-2)
- Safety (upadacitinib): increased risks of acne RR 6.23, nasopharyngitis RR 1.36, and elevated blood creatine phosphokinase (CPK) RR 2.41. (he2024januskinaseinhibitors pages 1-2)
Overall treatment-emergent adverse events (TEAEs) were increased for JAK inhibitors vs placebo (RR 1.14, 95% CI 1.02–1.28), with higher TEAE risk for systemic vs topical JAK inhibitors in the umbrella review’s synthesis. (he2024januskinaseinhibitors pages 8-11)
A completed AbbVie trial (ClinicalTrials.gov NCT05507580; posted/updated 2023) evaluated a treat-to-target/dose-flexibility strategy for upadacitinib in moderate-to-severe atopic dermatitis, using EASI90 at Week 24 as a primary endpoint and including EASI75/EASI100 among secondary outcomes, illustrating how JAK1 inhibition is operationalized in clinical protocols and endpoint selection. (NCT05507580 chunk 1)
URL: https://clinicaltrials.gov/study/NCT05507580 (NCT05507580 chunk 1)
Structural and signaling reviews converge on a model in which JAK1 is an adaptable receptor-bound kinase whose FERM–SH2 module encodes receptor specificity (box1/box2 recognition), while the pseudokinase domain encodes autoinhibitory restraint that can be released by receptor-driven geometry and dimerization, thereby controlling kinase output to STATs. (lv2024thejakstatpathway pages 12-15, lv2024thejakstatpathway media faa97556)
Pharmacology-focused reviews caution that clinical “JAK1 selectivity” should be interpreted functionally (pathway inhibition over dosing intervals and in tissues) rather than as a fixed biochemical property, because selectivity depends on dose, exposure, assay context, and the cooperative nature of JAK pairing at receptors. (taylor2024differentialpropertiesof pages 2-4)
This report focuses on mechanistic, structural, and translational/therapeutic evidence available in the retrieved 2023–2024 reviews and evidence syntheses; it does not include a mouse-specific curated phenotype compendium or a comprehensive tissue expression atlas because such primary datasets were not retrieved in the current evidence set. (wei2024januskinasesand pages 1-3, lv2024thejakstatpathway pages 12-15)
ClinicalTrials.gov registry excerpts retrieved here describe trial design and endpoints but do not provide results; quantitative efficacy/safety statistics are therefore drawn primarily from the 2024 umbrella review meta-analytic summaries rather than from individual newly posted trial result tables. (NCT05507580 chunk 1, he2024januskinaseinhibitors pages 1-2)
References
(wei2024januskinasesand pages 1-3): Yazi Wei and Tiantai Zhang. Janus kinases and autoimmunity: bridging pathways to therapy. International Journal of Drug Discovery and Pharmacology, pages 100007, Jun 2024. URL: https://doi.org/10.53941/ijddp.2024.100007, doi:10.53941/ijddp.2024.100007. This article has 1 citations.
(lv2024thejakstatpathway pages 12-15): You Lv, Jianxun Qi, Jeff J. Babon, Longxing Cao, Guohuang Fan, Jiajia Lang, Jin Zhang, Pengbing Mi, B. Kobe, and Faming Wang. The jak-stat pathway: from structural biology to cytokine engineering. Signal Transduction and Targeted Therapy, Aug 2024. URL: https://doi.org/10.1038/s41392-024-01934-w, doi:10.1038/s41392-024-01934-w. This article has 111 citations and is from a peer-reviewed journal.
(taylor2024differentialpropertiesof pages 2-4): Peter C Taylor, Ernest Choy, Xenofon Baraliakos, Zoltan Szekanecz, Ricardo M Xavier, John D Isaacs, Sander Strengholt, Julie M Parmentier, Ralph Lippe, and Yoshiya Tanaka. Differential properties of janus kinase inhibitors in the treatment of immune-mediated inflammatory diseases. Rheumatology (Oxford, England), 63:298-308, Aug 2024. URL: https://doi.org/10.1093/rheumatology/kead448, doi:10.1093/rheumatology/kead448. This article has 104 citations.
(lv2024thejakstatpathway media faa97556): You Lv, Jianxun Qi, Jeff J. Babon, Longxing Cao, Guohuang Fan, Jiajia Lang, Jin Zhang, Pengbing Mi, B. Kobe, and Faming Wang. The jak-stat pathway: from structural biology to cytokine engineering. Signal Transduction and Targeted Therapy, Aug 2024. URL: https://doi.org/10.1038/s41392-024-01934-w, doi:10.1038/s41392-024-01934-w. This article has 111 citations and is from a peer-reviewed journal.
(sarapultsev2023jakstatsignalingin pages 5-7): Alexey Sarapultsev, Evgenii Gusev, M. Komelkova, Irina Utepova, Shanshan Luo, and Desheng Hu. Jak-stat signaling in inflammation and stress-related diseases: implications for therapeutic interventions. Molecular Biomedicine, Nov 2023. URL: https://doi.org/10.1186/s43556-023-00151-1, doi:10.1186/s43556-023-00151-1. This article has 211 citations and is from a peer-reviewed journal.
(sarapultsev2023jakstatsignalingin pages 4-5): Alexey Sarapultsev, Evgenii Gusev, M. Komelkova, Irina Utepova, Shanshan Luo, and Desheng Hu. Jak-stat signaling in inflammation and stress-related diseases: implications for therapeutic interventions. Molecular Biomedicine, Nov 2023. URL: https://doi.org/10.1186/s43556-023-00151-1, doi:10.1186/s43556-023-00151-1. This article has 211 citations and is from a peer-reviewed journal.
(paolino2025serumlipidsalterations pages 2-4): Giovanni Paolino, Mario Valenti, Andrea Carugno, Matteo Bianco, Dario Didona, Matteo Riccardo Di Nicola, Pier Luigi Acutis, Carmen Cantisani, Vittoria Giulia Bianchi, Nicola Zerbinati, Alessandra Narcisi, Antonio Costanzo, and Santo Raffaele Mercuri. Serum lipids alterations in patients under systemic jak inhibitors treatments in dermatology: clinical aspects and management. Medicina, 61:54, Jan 2025. URL: https://doi.org/10.3390/medicina61010054, doi:10.3390/medicina61010054. This article has 13 citations.
(jarneborn2025thedualedgedsword pages 2-4): Anders Jarneborn, Pradeep Kumar Kopparapu, and Tao Jin. The dual-edged sword: risks and benefits of jak inhibitors in infections. Pathogens, 14:324, Mar 2025. URL: https://doi.org/10.3390/pathogens14040324, doi:10.3390/pathogens14040324. This article has 7 citations.
(he2024januskinaseinhibitors pages 1-2): Qingying He, Xin Xie, Qian Chen, Wenquan Li, Zongzhou Song, Xurui Wang, Xiao Ma, Jinhao Zeng, and Jing Guo. Janus kinase inhibitors in atopic dermatitis: an umbrella review of meta-analyses. Frontiers in Immunology, Feb 2024. URL: https://doi.org/10.3389/fimmu.2024.1342810, doi:10.3389/fimmu.2024.1342810. This article has 18 citations and is from a peer-reviewed journal.
(he2024januskinaseinhibitors pages 8-11): Qingying He, Xin Xie, Qian Chen, Wenquan Li, Zongzhou Song, Xurui Wang, Xiao Ma, Jinhao Zeng, and Jing Guo. Janus kinase inhibitors in atopic dermatitis: an umbrella review of meta-analyses. Frontiers in Immunology, Feb 2024. URL: https://doi.org/10.3389/fimmu.2024.1342810, doi:10.3389/fimmu.2024.1342810. This article has 18 citations and is from a peer-reviewed journal.
(NCT05507580 chunk 1): A Study to Assess Treat-to-Target and Dosing Flexibility of Oral Upadacitinib Tablets in Adult Participants With Moderate to Severe Atopic Dermatitis. AbbVie. 2023. ClinicalTrials.gov Identifier: NCT05507580