{"gene":"JAG2","run_date":"2026-04-28T18:06:54","timeline":{"discoveries":[{"year":2005,"finding":"JAG2 and DLL1 act synergistically as Notch ligands to regulate hair cell differentiation in the cochlea, likely signaling through the NOTCH1 receptor; loss of both ligands causes supernumerary hair cells primarily through a cell fate switch rather than excess proliferation, and the Notch pathway also controls cellular proliferation in the organ of Corti.","method":"Genetic double-mutant analysis (Dll1/Jag2 double knockout mice), conditional inactivation of Notch1, in situ hybridization, cell fate tracing","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 — reciprocal genetic epistasis with conditional receptor inactivation, replicated across multiple mutant combinations","pmids":["16141228"],"is_preprint":false},{"year":2000,"finding":"JAG2 activation of Notch in cochlear progenitor cells acts to suppress Math1 expression, possibly through induction of the downstream Notch target HES5, thereby controlling hair cell vs. supporting cell fate; Jag2 mutant cochleae show expanded Math1 expression and dramatically reduced HES5.","method":"In situ hybridization for Math1 and HES5 in wild-type vs. Jag2deltaDSL mutant cochleae","journal":"Journal of the Association for Research in Otolaryngology","confidence":"Medium","confidence_rationale":"Tier 2 — clean genetic KO with defined molecular readouts, single lab","pmids":["11545143"],"is_preprint":false},{"year":2004,"finding":"JAG2 overexpression in malignant plasma cells induces secretion of IL-6, VEGF, and IGF-1 from stromal cells via Notch-1 signaling; this induction is blocked by anti-Notch-1 monoclonal antibodies targeting the JAG2-binding sequence of Notch-1. JAG2 overexpression is caused by hypomethylation of its promoter in myeloma cells.","method":"In vitro co-culture assay with anti-Notch-1 antibody blocking, methylation analysis, cytokine measurement","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 — functional co-culture with antibody blocking and cytokine readout, single lab","pmids":["15292061"],"is_preprint":false},{"year":2006,"finding":"JAG2 signals through NOTCH1 in oral epithelium to drive periderm differentiation and prevent premature palatal adhesion; Jag2-deficient mice show attenuated Notch1 activation in oral periderm, disrupted periderm ultrastructure, and their tongue fuses to wild-type palatal shelves in recombinant explant culture.","method":"Genetic knockout, immunostaining for activated Notch1, ultrastructural analysis, recombinant explant co-culture","journal":"Developmental Dynamics","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods including explant rescue experiment, clean genetic KO","pmids":["16607638"],"is_preprint":false},{"year":2007,"finding":"DeltaNp63 transcriptionally enhances Jag2 expression in thymic epithelial cells; p63-null thymi phenocopy Jag2-null thymi in showing reduced gamma-delta T cell formation, placing DeltaNp63 upstream of Jag2 in thymic development.","method":"Genetic complementation of p63-/- mice with TAp63alpha or DeltaNp63alpha transgenes, in vivo gene expression analysis, comparison of p63-/- and Jag2-/- thymic phenotypes","journal":"PNAS","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo genetic complementation with defined downstream gene expression readout, single lab","pmids":["17626181"],"is_preprint":false},{"year":2009,"finding":"Loss of the SMRT/NCoR2 corepressor in multiple myeloma leads to aberrant histone acetylation at the JAG2 promoter, causing JAG2 overexpression; restoration of SMRT function suppresses JAG2 and induces myeloma cell apoptosis.","method":"Chromatin analysis of JAG2 promoter acetylation, SMRT expression analysis in cell lines and patient samples, functional SMRT restoration experiments","journal":"Cancer Research","confidence":"Medium","confidence_rationale":"Tier 2 — epigenetic mechanism with functional rescue experiment, single lab","pmids":["19417136"],"is_preprint":false},{"year":2010,"finding":"JAG2 is a direct transcriptional target of ectopic Myc in human B cells; Myc-driven JAG2 activates Notch signaling and promotes hypoxic cell proliferation and in vivo tumorigenesis; inhibition of JAG2 by RNAi or the gamma-secretase inhibitor DAPT preferentially suppresses the neoplastic state.","method":"Inducible Myc P493-6 B-cell model, RNAi knockdown of JAG2, gamma-secretase inhibitor (DAPT) treatment in vitro and in vivo, direct Myc ChIP/induction assay","journal":"PNAS","confidence":"High","confidence_rationale":"Tier 2 — direct target identification with multiple functional assays (RNAi, pharmacological inhibition, in vitro and in vivo), replicated with orthogonal methods in one study","pmids":["20133585"],"is_preprint":false},{"year":2011,"finding":"JAG2 is transcriptionally activated by hypoxia in a HIF-1alpha-dependent manner; hypoxic JAG2 induction elevates Notch activity (increased intracellular Notch1 and HEY1 target gene), and JAG2 expressed by hypoxic tumor cells promotes endothelial cell tube formation in co-culture.","method":"siRNA knockdown of HIF-1alpha, Notch target gene measurement (icN1, HEY1), co-culture tube formation assay with JAG2 siRNA","journal":"Molecular Cancer Research","confidence":"Medium","confidence_rationale":"Tier 2 — mechanistic pathway with HIF-1alpha dependence shown by siRNA, functional co-culture assay, single lab","pmids":["21402725"],"is_preprint":false},{"year":2012,"finding":"JAG2 expression is required for self-renewal (clonogenic colony formation) and in vivo tumor formation of myeloma cells; blocking JAG-NOTCH interactions with NOTCH-Fc chimeric molecules impairs colony formation, and JAG2 silencing blocks both colony and tumor formation.","method":"JAG2 siRNA silencing, NOTCH-Fc chimeric molecule blocking, semi-solid colony assay, xenograft tumor formation in immunocompromised mice","journal":"Blood Cells, Molecules & Diseases","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function with defined phenotype and receptor-blocking experiment, single lab","pmids":["22341562"],"is_preprint":false},{"year":2013,"finding":"JAG2 promotes Notch activity, clonogenic growth, motility, and invasion in uveal melanoma cells; overexpression increases soft-agar colony formation and invasion, and shRNA-mediated knockdown suppresses growth and invasion, with a corresponding increase in JAG2 and Hes1 mRNA in invasive cells.","method":"JAG2-GFP overexpression constructs, shRNA knockdown, soft-agar colony assay, wound-healing and transwell invasion assays, Hes1 mRNA measurement","journal":"Investigative Ophthalmology & Visual Science","confidence":"Medium","confidence_rationale":"Tier 2 — bidirectional gain- and loss-of-function with multiple phenotypic readouts, single lab","pmids":["23211831"],"is_preprint":false},{"year":2014,"finding":"JAG2 is identified as a direct MYC transcriptional target in medulloblastoma; MYC-driven transcriptional activation of JAG2 is specific to Group 3 (MYC-amplified) medulloblastoma and links the MYC oncogene to Notch pathway activation in these tumors.","method":"Expression analysis in MB cohorts, in vitro MYC activation studies, qPCR for JAG2 in MYC-high vs. low cells","journal":"Acta Neuropathologica Communications","confidence":"Medium","confidence_rationale":"Tier 2 — mechanistic link established between MYC and JAG2 transcription with patient cohort validation, single lab","pmids":["24708907"],"is_preprint":false},{"year":2017,"finding":"JAG2 expression in colorectal cancer is regulated by Wnt/beta-catenin signaling (APC deletion or beta-catenin knockdown modulates JAG2); JAG2 promotes chemoresistance through p21, as forced p21 expression rescues sensitivity of JAG2-knockdown cells and p21-null cells are insensitive to JAG2 knockdown.","method":"Pharmacological beta-catenin inhibition, siRNA knockdown, Apc conditional knockout mice, in vivo tumorigenicity assay, p21 forced expression rescue experiment","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 — genetic and pharmacological epistasis with rescue experiment, single lab","pmids":["28881809"],"is_preprint":false},{"year":2018,"finding":"JAG2 signaling activates Notch in CD14+ monocytes to drive their differentiation into LCH-like cells (acquiring CD1a and langerin), inducing an LCH gene signature; Notch inhibition suppresses this phenotype.","method":"In vitro JAG2 co-culture of monocytes, Notch inhibitor treatment, flow cytometry, gene expression profiling","journal":"Journal of Leukocyte Biology","confidence":"Medium","confidence_rationale":"Tier 2 — functional differentiation assay with pharmacological inhibition, single lab","pmids":["30296338"],"is_preprint":false},{"year":2019,"finding":"JAG2 activates Notch2/Hes1/Hey2 signaling in nucleus pulposus cells to promote proliferation via cyclin D1 and PI3K/Akt and Wnt/beta-catenin pathways, and inhibits TNF-alpha-induced apoptosis by suppressing formation of the RIP1-FADD-caspase-8 complex; intradiscal injection of JAG2 alleviates disc degeneration in rats.","method":"Recombinant JAG2 protein treatment, Notch2/Hes1/Hey2 siRNA, cell cycle analysis, Co-IP for RIP1-FADD-caspase-8 complex, PI3K/Akt and Wnt pathway inhibitors, intradiscal rat injection model","journal":"Arthritis Research & Therapy","confidence":"Medium","confidence_rationale":"Tier 2 — multiple pathway analyses with in vivo validation, single lab","pmids":["31619270"],"is_preprint":false},{"year":2019,"finding":"JAG2 promotes migration and invasion of colorectal cancer cells via a non-canonical Notch, non-EMT pathway involving mutual regulation with PRAF2; JAG2-rich exosomes are released from CRC cells in a PRAF2-dependent manner and regulate metastasis in a paracrine fashion.","method":"siRNA knockdown, transcriptome microarray, Co-expression analysis, exosome isolation, paracrine co-culture assay","journal":"Cancer Cell International","confidence":"Medium","confidence_rationale":"Tier 3 — non-canonical pathway proposal supported by siRNA and exosome experiments, single lab","pmids":["31198409"],"is_preprint":false},{"year":2021,"finding":"Biallelic pathogenic variants in JAG2 cause a muscular dystrophy (LGMD R27); Jag2 downregulation in murine myoblasts leads to downregulation of multiple Notch pathway components including Megf10; transcriptome analysis of patient muscle shows misregulation of myogenesis genes including PAX7, implicating Notch pathway dysfunction as the disease mechanism.","method":"Whole-exome sequencing, muscle transcriptome analysis, Jag2 siRNA knockdown in murine myoblasts, Drosophila genetic interaction studies (Serrate/Drpr), in silico structural prediction of missense variants","journal":"American Journal of Human Genetics","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal approaches (human genetics, mouse knockdown, fly genetics) linking JAG2 to Notch-dependent myogenesis","pmids":["33861953"],"is_preprint":false},{"year":2021,"finding":"MSC supernatant inhibits IL-6-mediated STAT3 phosphorylation to activate the p63-JAG2 signaling axis in basal lung epithelial cells, promoting p63+ cell proliferation and repair; the IL-6-p-STAT3-p63-JAG2 pathway was identified as the mechanistic link between MSC secretome treatment and attenuation of acute lung injury.","method":"Mouse bleomycin-induced ALI model, immunofluorescence, Western blot, flow cytometry, siRNA pathway manipulation","journal":"Stem Cell Research & Therapy","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo model with molecular pathway dissection, single lab","pmids":["33781349"],"is_preprint":false},{"year":2022,"finding":"JAG1 and JAG2 undergo posttranslational modifications in tracheobronchial epithelium: gamma-secretase complex (GSC) and glycogen synthase kinase 3 generate a JAG1 C-terminal peptide and regulate full-length JAG2 surface abundance; these distinct JAG1/JAG2 assemblies regulate Notch signal strength and determine goblet vs. ciliated cell fate in a WNT-independent manner.","method":"Human air-liquid-interface cultures, gamma-secretase inhibitors, neutralizing peptides/antibodies, WNT pathway agonists/antagonists, RNA-Seq, biochemical fractionation","journal":"JCI Insight","confidence":"Medium","confidence_rationale":"Tier 2 — biochemical PTM characterization with multiple pharmacological tools and transcriptomic readout, single lab","pmids":["35819850"],"is_preprint":false},{"year":2024,"finding":"The JAG2/Notch1 signaling axis is the primary regulator of sebocyte differentiation in mouse skin; specific inhibition of JAG2 ligand or Notch1 receptor with monoclonal antibodies causes loss of mature sebocytes and accumulation of proliferative stem/progenitor cells, a phenotype that is reversible upon lifting Notch inhibition.","method":"Monoclonal therapeutic antibody inhibition of individual Notch ligands/receptors in mice, histology, cell proliferation assays","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 — specific ligand/receptor antibody targeting with reversibility demonstrated, strong mechanistic evidence for this specific axis","pmids":["39585329"],"is_preprint":false},{"year":2025,"finding":"Usp11 deubiquitinates JAG2 (and DLL1) to maintain their stability; loss of Usp11 reduces JAG2 ubiquitination, altering Notch signaling in marginal zone B cells and their survival after ionizing radiation.","method":"Co-IP and ubiquitination assays in Usp11-/- mice, flow cytometry, histological analysis, single-cell sequencing","journal":"Cell Death & Disease","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP and ubiquitination assay demonstrating deubiquitination of JAG2 by Usp11, with in vivo genetic KO validation","pmids":["39904982"],"is_preprint":false},{"year":2025,"finding":"CD146 activates NF-κB signaling to upregulate JAG2, which then activates Notch signaling to promote stemness and chemoresistance in hepatocellular carcinoma; JAG2 overexpression rescues Notch activity and stemness suppressed by CD146 knockdown.","method":"CD146 overexpression/knockdown, JAG2 overexpression rescue experiment, Notch signaling reporter, in vitro self-renewal and chemoresistance assays, xenograft","journal":"Cell Death & Disease","confidence":"Medium","confidence_rationale":"Tier 2 — epistasis rescue experiment placing JAG2 downstream of CD146/NF-κB in Notch activation, single lab","pmids":["40032820"],"is_preprint":false},{"year":2025,"finding":"Tumor-derived JAG2 activates NOTCH3 on macrophages, inducing STAT3 phosphorylation and CCL2 upregulation, driving an immunosuppressive M2-like, neurotrophic macrophage phenotype that promotes perineural invasion; disruption of JAG2-NOTCH3 signaling, STAT3 inhibition, or CCL2 blockade attenuates invasion in vitro and in vivo.","method":"Single-cell transcriptomics, ligand-receptor analysis, STAT3 inhibition, CCL2 neutralization, JAG2 knockdown, xenograft and sciatic nerve invasion models","journal":"International Journal of Biological Macromolecules","confidence":"Medium","confidence_rationale":"Tier 2 — mechanistic pathway (JAG2→NOTCH3→STAT3→CCL2) validated by multiple inhibition strategies in vitro and in vivo, single lab","pmids":["41916520"],"is_preprint":false},{"year":2024,"finding":"NEURL1 and NEURL2 (Neuralized-like) ubiquitin ligases do not activate JAG2 because JAG2 lacks the NxxN Neuralized binding motif present in DLL1 and JAG1, establishing differential regulation: NEURL proteins selectively activate only DLL1 and JAG1 among mammalian Notch ligands.","method":"Humanized Drosophila system, mammalian cell culture Notch activation assays, motif mutagenesis, comparison across all four mammalian Notch ligands","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 — reconstitution in two systems with motif analysis, but preprint","pmids":["bio_10.1101_2024.09.20.614084"],"is_preprint":true},{"year":2025,"finding":"JAG2 deficiency and pathogenic JAG2 variants impair Notch signaling and myogenic self-renewal and differentiation in muscle stem cells (MuSCs); MuEC-specific Jag2 knockout reduces MuSC self-renewal (trans-activation), while MuSC-specific Jag2 knockout reduces myogenic differentiation (cis-inhibition); hypomorphic Jag2 mutant mice show depleted MuSCs and impaired muscle regeneration; human reference JAG2 but not pathogenic variants rescues Drosophila Serrate deficiency.","method":"Cell-type-specific conditional Jag2 knockout mice, co-culture experiments, Drosophila Serrate rescue with human JAG2 constructs, hypomorphic Jag2 mutant mouse analysis, overexpression of pathogenic variants","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal in vivo genetic and cell biological approaches with cross-species validation, preprint","pmids":["bio_10.1101_2025.07.23.665646"],"is_preprint":true}],"current_model":"JAG2 is a canonical Notch ligand that activates Notch receptors (primarily NOTCH1 and NOTCH2) in trans on neighboring cells to regulate cell fate decisions across multiple tissues—including inner ear hair cells, oral/palatal epithelium, sebaceous gland, skeletal muscle stem cells, and immune cells—while its surface abundance and activity are regulated by posttranslational modifications (including deubiquitination by USP11 and processing by gamma-secretase/GSK3), its transcription is controlled by upstream factors including Myc, DeltaNp63, Wnt/beta-catenin, and HIF-1alpha, and it lacks the NxxN motif required for NEURL-mediated activation, distinguishing it mechanistically from JAG1 and DLL1."},"narrative":{"teleology":[{"year":2000,"claim":"Establishing JAG2 as a cochlear Notch ligand that controls hair cell versus supporting cell fate answered the question of which ligand mediates lateral inhibition in the inner ear, revealing that JAG2-dependent Notch activation suppresses Math1 and induces HES5 in cochlear progenitors.","evidence":"In situ hybridization of Math1 and HES5 in Jag2-deltaDSL mutant versus wild-type cochleae","pmids":["11545143"],"confidence":"Medium","gaps":["Whether JAG2 acts alone or redundantly with other ligands in the cochlea was not resolved","Direct receptor identity was not determined"]},{"year":2005,"claim":"Demonstrating synergistic action of JAG2 and DLL1 through NOTCH1 in the cochlea resolved the question of ligand redundancy, showing that the two ligands act cooperatively and that the supernumerary hair cell phenotype arises from a cell fate switch rather than excess proliferation.","evidence":"Double Dll1/Jag2 knockout mice and conditional Notch1 inactivation with cell fate tracing","pmids":["16141228"],"confidence":"High","gaps":["Quantitative contribution of each ligand individually was not fully resolved","Whether downstream effectors beyond HES5 differ between JAG2 and DLL1 signaling was not addressed"]},{"year":2004,"claim":"Identifying JAG2 as overexpressed in myeloma due to promoter hypomethylation and showing that it activates stromal NOTCH1 to induce pro-survival cytokines (IL-6, VEGF, IGF-1) established the first paracrine oncogenic function of JAG2, answering how tumor-stroma Notch signaling supports myeloma growth.","evidence":"Anti-Notch-1 antibody blocking in co-culture, methylation analysis of JAG2 promoter in myeloma cells","pmids":["15292061"],"confidence":"Medium","gaps":["Whether JAG2 signals to other Notch receptors in the myeloma niche was not tested","In vivo relevance in myeloma patients was not demonstrated"]},{"year":2006,"claim":"Showing that JAG2 signals through NOTCH1 in oral periderm to prevent premature palatal adhesion established JAG2 as essential for epithelial barrier formation, explaining the cleft palate phenotype of Jag2-null mice.","evidence":"Jag2 knockout mice, activated Notch1 immunostaining, recombinant explant co-culture","pmids":["16607638"],"confidence":"High","gaps":["Whether JAG2 controls periderm differentiation cell-autonomously or via juxtacrine signaling was not fully distinguished","Downstream transcriptional targets in periderm were not identified"]},{"year":2007,"claim":"Placing ΔNp63 upstream of JAG2 transcription in thymic epithelium answered the question of how p63 regulates γδ T cell development, establishing a ΔNp63→JAG2→Notch transcriptional cascade.","evidence":"Genetic complementation of p63-null mice with ΔNp63α transgenes, comparison of p63−/− and Jag2−/− thymic phenotypes","pmids":["17626181"],"confidence":"Medium","gaps":["Direct p63 binding to the JAG2 promoter was not shown","Whether JAG1 compensates for JAG2 loss in this context was not tested"]},{"year":2009,"claim":"Demonstrating that loss of SMRT/NCoR2 corepressor causes aberrant JAG2 promoter acetylation and overexpression in myeloma provided an epigenetic mechanism for JAG2 deregulation, complementing the earlier promoter hypomethylation finding.","evidence":"Chromatin analysis of JAG2 promoter, SMRT restoration suppressing JAG2 and inducing apoptosis in myeloma cells","pmids":["19417136"],"confidence":"Medium","gaps":["Relative contribution of methylation versus SMRT loss to JAG2 overexpression was not dissected","Whether SMRT directly binds the JAG2 promoter or acts indirectly was not resolved"]},{"year":2010,"claim":"Identifying JAG2 as a direct MYC transcriptional target that drives Notch-dependent tumorigenesis in B cells answered how the MYC oncogene co-opts Notch signaling, establishing a MYC→JAG2→Notch pathway relevant to lymphomagenesis.","evidence":"Inducible Myc P493-6 B-cell model, direct Myc ChIP at JAG2 locus, RNAi and gamma-secretase inhibitor treatment in vitro and in vivo","pmids":["20133585"],"confidence":"High","gaps":["Whether JAG2 is the sole mediator of MYC-driven Notch activation was not established","Specific Notch receptor engaged downstream was not identified"]},{"year":2011,"claim":"Showing that HIF-1α transcriptionally induces JAG2 under hypoxia to elevate Notch activity and promote angiogenesis answered how the tumor microenvironment regulates JAG2 expression, linking oxygen sensing to Notch ligand biology.","evidence":"HIF-1α siRNA knockdown, icN1 and HEY1 target gene measurement, co-culture endothelial tube formation assay","pmids":["21402725"],"confidence":"Medium","gaps":["Direct HIF-1α binding to JAG2 regulatory elements was not mapped","Whether JAG2-mediated angiogenesis requires cell contact or is exosome-mediated was not tested"]},{"year":2017,"claim":"Placing JAG2 downstream of Wnt/β-catenin signaling and upstream of p21-mediated chemoresistance in colorectal cancer answered how JAG2 integrates Wnt and Notch pathways to promote treatment resistance.","evidence":"APC conditional knockout mice, β-catenin knockdown, p21 forced expression rescue of JAG2-knockdown sensitivity","pmids":["28881809"],"confidence":"Medium","gaps":["Whether JAG2 directly transcriptionally regulates p21 or acts through Notch/HES was not shown","Relevance to patient chemotherapy response was not validated"]},{"year":2021,"claim":"Identifying biallelic JAG2 variants as the cause of LGMD R27 answered whether JAG2 is essential for human skeletal muscle maintenance, establishing that Notch pathway dysfunction in muscle stem cells underlies a progressive muscular dystrophy.","evidence":"Whole-exome sequencing in families, muscle transcriptome showing PAX7 and myogenesis gene misregulation, Jag2 siRNA in murine myoblasts, Drosophila Serrate/Draper genetic interaction","pmids":["33861953"],"confidence":"Medium","gaps":["Cell-type-specific (MuSC vs. MuEC) contributions of JAG2 to disease were not dissected","Whether disease variants are loss-of-function or dominant-negative was not fully resolved"]},{"year":2022,"claim":"Demonstrating that gamma-secretase and GSK3 regulate full-length JAG2 surface abundance in airway epithelium answered how posttranslational processing controls JAG2-mediated Notch signal strength to determine goblet versus ciliated cell fate.","evidence":"Human air-liquid interface cultures, gamma-secretase inhibitors, neutralizing antibodies, RNA-Seq, biochemical fractionation","pmids":["35819850"],"confidence":"Medium","gaps":["Specific GSK3 phosphorylation sites on JAG2 were not mapped","Whether this processing mechanism operates in non-airway tissues was not tested"]},{"year":2024,"claim":"Specific antibody-mediated blockade of JAG2 or NOTCH1 causing reversible loss of mature sebocytes established the JAG2/Notch1 axis as the primary differentiation signal in the sebaceous gland, answering which ligand-receptor pair drives this lineage.","evidence":"Monoclonal antibody inhibition of individual Notch ligands and receptors in mice, histology, cell proliferation assays, reversibility upon withdrawal","pmids":["39585329"],"confidence":"High","gaps":["Downstream transcription factors activated by JAG2/Notch1 in sebocytes were not identified","Human sebaceous gland relevance was not directly shown"]},{"year":2025,"claim":"Discovery that USP11 deubiquitinates JAG2 to maintain its stability answered how JAG2 protein turnover is regulated, revealing that ubiquitin-dependent degradation controls JAG2-mediated Notch signaling in marginal zone B cells.","evidence":"Co-IP and ubiquitination assays in Usp11−/− mice, flow cytometry of B cell subsets","pmids":["39904982"],"confidence":"Medium","gaps":["Specific ubiquitin chain types on JAG2 were not characterized","Whether other deubiquitinases compensate for USP11 was not tested","Reciprocal validation (e.g., JAG2 pulldown of USP11) not explicitly described"]},{"year":2025,"claim":"Showing that tumor-derived JAG2 activates NOTCH3/STAT3/CCL2 on macrophages to create an immunosuppressive niche promoting perineural invasion answered how JAG2 shapes the tumor immune microenvironment beyond direct tumor cell effects.","evidence":"Single-cell transcriptomics, ligand-receptor analysis, STAT3 inhibition, CCL2 neutralization, JAG2 knockdown, xenograft and sciatic nerve invasion models","pmids":["41916520"],"confidence":"Medium","gaps":["Whether this JAG2-NOTCH3 axis operates in other tumor types was not tested","Structural basis for JAG2 selectivity for NOTCH3 versus NOTCH1 was not addressed"]},{"year":null,"claim":"Key open questions include the structural determinants of JAG2 receptor selectivity (NOTCH1 vs. NOTCH2 vs. NOTCH3), the identity of E3 ubiquitin ligases that target JAG2 for degradation (given its insensitivity to NEURL), and whether JAG2's cis-inhibitory and trans-activating functions are structurally separable.","evidence":"","pmids":[],"confidence":"Low","gaps":["No crystal structure of JAG2-Notch complex exists","E3 ligase(s) targeting JAG2 for ubiquitination are unknown","Relative contribution of cis-inhibition versus trans-activation in muscle stem cell biology requires further dissection"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[0,1,2,3,6,13,18,21]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,2,3,18]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[17,19]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,2,3,6,13,18,21]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,1,3,4,15,18,23]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2,5,6,8,9,10,11,14,20,21]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[4,12,21]}],"complexes":[],"partners":["NOTCH1","NOTCH2","NOTCH3","USP11","DLL1","PRAF2"],"other_free_text":[]},"mechanistic_narrative":"JAG2 is a transmembrane Notch ligand that activates Notch receptors on neighboring cells to govern binary cell fate decisions across diverse tissues, including inner ear hair cells, oral periderm, sebaceous glands, muscle stem cells, immune cells, and multiple tumor types. JAG2 signals primarily through NOTCH1 to suppress progenitor identity and promote differentiation—exemplified by lateral inhibition of hair cell fate via Math1 repression and HES5 induction in the cochlea [PMID:11545143, PMID:16141228], periderm maturation in oral epithelium [PMID:16607638], and sebocyte differentiation from skin progenitors [PMID:39585329]—and also signals through NOTCH2 and NOTCH3 in context-dependent settings such as nucleus pulposus cell survival [PMID:31619270] and macrophage polarization [PMID:41916520]. Its surface abundance is regulated by USP11-mediated deubiquitination [PMID:39904982] and gamma-secretase/GSK3-dependent processing [PMID:35819850], while its transcription is driven by MYC, ΔNp63, Wnt/β-catenin, HIF-1α, and NF-κB depending on cellular context [PMID:20133585, PMID:17626181, PMID:28881809, PMID:21402725, PMID:40032820]. Biallelic loss-of-function variants in JAG2 cause limb-girdle muscular dystrophy type R27 (LGMD R27), linked to impaired Notch-dependent muscle stem cell self-renewal and myogenesis [PMID:33861953]."},"prefetch_data":{"uniprot":{"accession":"Q9Y219","full_name":"Protein jagged-2","aliases":[],"length_aa":1238,"mass_kda":133.4,"function":"Putative Notch ligand involved in the mediation of Notch signaling. Involved in limb development (By similarity)","subcellular_location":"Membrane","url":"https://www.uniprot.org/uniprotkb/Q9Y219/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/JAG2","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CANX","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/JAG2","total_profiled":1310},"omim":[{"mim_id":"619566","title":"MUSCULAR DYSTROPHY, LIMB-GIRDLE, AUTOSOMAL RECESSIVE 27; LGMDR27","url":"https://www.omim.org/entry/619566"},{"mim_id":"611141","title":"MIB E3 UBIQUITIN PROTEIN LIGASE 2; MIB2","url":"https://www.omim.org/entry/611141"},{"mim_id":"608582","title":"EPIDERMAL GROWTH FACTOR-LIKE 7; EGFL7","url":"https://www.omim.org/entry/608582"},{"mim_id":"608183","title":"CHONDROITIN SULFATE SYNTHASE 1; CHSY1","url":"https://www.omim.org/entry/608183"},{"mim_id":"607199","title":"INTERFERON REGULATORY FACTOR 6; IRF6","url":"https://www.omim.org/entry/607199"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/JAG2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9Y219","domains":[{"cath_id":"2.60.40.3510","chopping":"25-211","consensus_level":"high","plddt":81.0837,"start":25,"end":211},{"cath_id":"2.10.25.10","chopping":"427-462","consensus_level":"medium","plddt":78.3297,"start":427,"end":462},{"cath_id":"2.10.25.10","chopping":"541-573","consensus_level":"medium","plddt":77.0209,"start":541,"end":573},{"cath_id":"2.10.25.10","chopping":"700-753","consensus_level":"medium","plddt":67.9144,"start":700,"end":753},{"cath_id":"-","chopping":"837-899","consensus_level":"medium","plddt":78.0016,"start":837,"end":899},{"cath_id":"-","chopping":"905-951_958-1074","consensus_level":"medium","plddt":79.0824,"start":905,"end":1074}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y219","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y219-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y219-F1-predicted_aligned_error_v6.png","plddt_mean":72.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=JAG2","jax_strain_url":"https://www.jax.org/strain/search?query=JAG2"},"sequence":{"accession":"Q9Y219","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y219.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y219/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y219"}},"corpus_meta":[{"pmid":"16141228","id":"PMC_16141228","title":"The 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receptor; loss of both ligands causes supernumerary hair cells primarily through a cell fate switch rather than excess proliferation, and the Notch pathway also controls cellular proliferation in the organ of Corti.\",\n      \"method\": \"Genetic double-mutant analysis (Dll1/Jag2 double knockout mice), conditional inactivation of Notch1, in situ hybridization, cell fate tracing\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal genetic epistasis with conditional receptor inactivation, replicated across multiple mutant combinations\",\n      \"pmids\": [\"16141228\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"JAG2 activation of Notch in cochlear progenitor cells acts to suppress Math1 expression, possibly through induction of the downstream Notch target HES5, thereby controlling hair cell vs. supporting cell fate; Jag2 mutant cochleae show expanded Math1 expression and dramatically reduced HES5.\",\n      \"method\": \"In situ hybridization for Math1 and HES5 in wild-type vs. Jag2deltaDSL mutant cochleae\",\n      \"journal\": \"Journal of the Association for Research in Otolaryngology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean genetic KO with defined molecular readouts, single lab\",\n      \"pmids\": [\"11545143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"JAG2 overexpression in malignant plasma cells induces secretion of IL-6, VEGF, and IGF-1 from stromal cells via Notch-1 signaling; this induction is blocked by anti-Notch-1 monoclonal antibodies targeting the JAG2-binding sequence of Notch-1. JAG2 overexpression is caused by hypomethylation of its promoter in myeloma cells.\",\n      \"method\": \"In vitro co-culture assay with anti-Notch-1 antibody blocking, methylation analysis, cytokine measurement\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional co-culture with antibody blocking and cytokine readout, single lab\",\n      \"pmids\": [\"15292061\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"JAG2 signals through NOTCH1 in oral epithelium to drive periderm differentiation and prevent premature palatal adhesion; Jag2-deficient mice show attenuated Notch1 activation in oral periderm, disrupted periderm ultrastructure, and their tongue fuses to wild-type palatal shelves in recombinant explant culture.\",\n      \"method\": \"Genetic knockout, immunostaining for activated Notch1, ultrastructural analysis, recombinant explant co-culture\",\n      \"journal\": \"Developmental Dynamics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including explant rescue experiment, clean genetic KO\",\n      \"pmids\": [\"16607638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"DeltaNp63 transcriptionally enhances Jag2 expression in thymic epithelial cells; p63-null thymi phenocopy Jag2-null thymi in showing reduced gamma-delta T cell formation, placing DeltaNp63 upstream of Jag2 in thymic development.\",\n      \"method\": \"Genetic complementation of p63-/- mice with TAp63alpha or DeltaNp63alpha transgenes, in vivo gene expression analysis, comparison of p63-/- and Jag2-/- thymic phenotypes\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo genetic complementation with defined downstream gene expression readout, single lab\",\n      \"pmids\": [\"17626181\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Loss of the SMRT/NCoR2 corepressor in multiple myeloma leads to aberrant histone acetylation at the JAG2 promoter, causing JAG2 overexpression; restoration of SMRT function suppresses JAG2 and induces myeloma cell apoptosis.\",\n      \"method\": \"Chromatin analysis of JAG2 promoter acetylation, SMRT expression analysis in cell lines and patient samples, functional SMRT restoration experiments\",\n      \"journal\": \"Cancer Research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — epigenetic mechanism with functional rescue experiment, single lab\",\n      \"pmids\": [\"19417136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"JAG2 is a direct transcriptional target of ectopic Myc in human B cells; Myc-driven JAG2 activates Notch signaling and promotes hypoxic cell proliferation and in vivo tumorigenesis; inhibition of JAG2 by RNAi or the gamma-secretase inhibitor DAPT preferentially suppresses the neoplastic state.\",\n      \"method\": \"Inducible Myc P493-6 B-cell model, RNAi knockdown of JAG2, gamma-secretase inhibitor (DAPT) treatment in vitro and in vivo, direct Myc ChIP/induction assay\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct target identification with multiple functional assays (RNAi, pharmacological inhibition, in vitro and in vivo), replicated with orthogonal methods in one study\",\n      \"pmids\": [\"20133585\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"JAG2 is transcriptionally activated by hypoxia in a HIF-1alpha-dependent manner; hypoxic JAG2 induction elevates Notch activity (increased intracellular Notch1 and HEY1 target gene), and JAG2 expressed by hypoxic tumor cells promotes endothelial cell tube formation in co-culture.\",\n      \"method\": \"siRNA knockdown of HIF-1alpha, Notch target gene measurement (icN1, HEY1), co-culture tube formation assay with JAG2 siRNA\",\n      \"journal\": \"Molecular Cancer Research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic pathway with HIF-1alpha dependence shown by siRNA, functional co-culture assay, single lab\",\n      \"pmids\": [\"21402725\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"JAG2 expression is required for self-renewal (clonogenic colony formation) and in vivo tumor formation of myeloma cells; blocking JAG-NOTCH interactions with NOTCH-Fc chimeric molecules impairs colony formation, and JAG2 silencing blocks both colony and tumor formation.\",\n      \"method\": \"JAG2 siRNA silencing, NOTCH-Fc chimeric molecule blocking, semi-solid colony assay, xenograft tumor formation in immunocompromised mice\",\n      \"journal\": \"Blood Cells, Molecules & Diseases\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined phenotype and receptor-blocking experiment, single lab\",\n      \"pmids\": [\"22341562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"JAG2 promotes Notch activity, clonogenic growth, motility, and invasion in uveal melanoma cells; overexpression increases soft-agar colony formation and invasion, and shRNA-mediated knockdown suppresses growth and invasion, with a corresponding increase in JAG2 and Hes1 mRNA in invasive cells.\",\n      \"method\": \"JAG2-GFP overexpression constructs, shRNA knockdown, soft-agar colony assay, wound-healing and transwell invasion assays, Hes1 mRNA measurement\",\n      \"journal\": \"Investigative Ophthalmology & Visual Science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — bidirectional gain- and loss-of-function with multiple phenotypic readouts, single lab\",\n      \"pmids\": [\"23211831\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"JAG2 is identified as a direct MYC transcriptional target in medulloblastoma; MYC-driven transcriptional activation of JAG2 is specific to Group 3 (MYC-amplified) medulloblastoma and links the MYC oncogene to Notch pathway activation in these tumors.\",\n      \"method\": \"Expression analysis in MB cohorts, in vitro MYC activation studies, qPCR for JAG2 in MYC-high vs. low cells\",\n      \"journal\": \"Acta Neuropathologica Communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic link established between MYC and JAG2 transcription with patient cohort validation, single lab\",\n      \"pmids\": [\"24708907\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"JAG2 expression in colorectal cancer is regulated by Wnt/beta-catenin signaling (APC deletion or beta-catenin knockdown modulates JAG2); JAG2 promotes chemoresistance through p21, as forced p21 expression rescues sensitivity of JAG2-knockdown cells and p21-null cells are insensitive to JAG2 knockdown.\",\n      \"method\": \"Pharmacological beta-catenin inhibition, siRNA knockdown, Apc conditional knockout mice, in vivo tumorigenicity assay, p21 forced expression rescue experiment\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic and pharmacological epistasis with rescue experiment, single lab\",\n      \"pmids\": [\"28881809\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"JAG2 signaling activates Notch in CD14+ monocytes to drive their differentiation into LCH-like cells (acquiring CD1a and langerin), inducing an LCH gene signature; Notch inhibition suppresses this phenotype.\",\n      \"method\": \"In vitro JAG2 co-culture of monocytes, Notch inhibitor treatment, flow cytometry, gene expression profiling\",\n      \"journal\": \"Journal of Leukocyte Biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional differentiation assay with pharmacological inhibition, single lab\",\n      \"pmids\": [\"30296338\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"JAG2 activates Notch2/Hes1/Hey2 signaling in nucleus pulposus cells to promote proliferation via cyclin D1 and PI3K/Akt and Wnt/beta-catenin pathways, and inhibits TNF-alpha-induced apoptosis by suppressing formation of the RIP1-FADD-caspase-8 complex; intradiscal injection of JAG2 alleviates disc degeneration in rats.\",\n      \"method\": \"Recombinant JAG2 protein treatment, Notch2/Hes1/Hey2 siRNA, cell cycle analysis, Co-IP for RIP1-FADD-caspase-8 complex, PI3K/Akt and Wnt pathway inhibitors, intradiscal rat injection model\",\n      \"journal\": \"Arthritis Research & Therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple pathway analyses with in vivo validation, single lab\",\n      \"pmids\": [\"31619270\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"JAG2 promotes migration and invasion of colorectal cancer cells via a non-canonical Notch, non-EMT pathway involving mutual regulation with PRAF2; JAG2-rich exosomes are released from CRC cells in a PRAF2-dependent manner and regulate metastasis in a paracrine fashion.\",\n      \"method\": \"siRNA knockdown, transcriptome microarray, Co-expression analysis, exosome isolation, paracrine co-culture assay\",\n      \"journal\": \"Cancer Cell International\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — non-canonical pathway proposal supported by siRNA and exosome experiments, single lab\",\n      \"pmids\": [\"31198409\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Biallelic pathogenic variants in JAG2 cause a muscular dystrophy (LGMD R27); Jag2 downregulation in murine myoblasts leads to downregulation of multiple Notch pathway components including Megf10; transcriptome analysis of patient muscle shows misregulation of myogenesis genes including PAX7, implicating Notch pathway dysfunction as the disease mechanism.\",\n      \"method\": \"Whole-exome sequencing, muscle transcriptome analysis, Jag2 siRNA knockdown in murine myoblasts, Drosophila genetic interaction studies (Serrate/Drpr), in silico structural prediction of missense variants\",\n      \"journal\": \"American Journal of Human Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal approaches (human genetics, mouse knockdown, fly genetics) linking JAG2 to Notch-dependent myogenesis\",\n      \"pmids\": [\"33861953\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MSC supernatant inhibits IL-6-mediated STAT3 phosphorylation to activate the p63-JAG2 signaling axis in basal lung epithelial cells, promoting p63+ cell proliferation and repair; the IL-6-p-STAT3-p63-JAG2 pathway was identified as the mechanistic link between MSC secretome treatment and attenuation of acute lung injury.\",\n      \"method\": \"Mouse bleomycin-induced ALI model, immunofluorescence, Western blot, flow cytometry, siRNA pathway manipulation\",\n      \"journal\": \"Stem Cell Research & Therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo model with molecular pathway dissection, single lab\",\n      \"pmids\": [\"33781349\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"JAG1 and JAG2 undergo posttranslational modifications in tracheobronchial epithelium: gamma-secretase complex (GSC) and glycogen synthase kinase 3 generate a JAG1 C-terminal peptide and regulate full-length JAG2 surface abundance; these distinct JAG1/JAG2 assemblies regulate Notch signal strength and determine goblet vs. ciliated cell fate in a WNT-independent manner.\",\n      \"method\": \"Human air-liquid-interface cultures, gamma-secretase inhibitors, neutralizing peptides/antibodies, WNT pathway agonists/antagonists, RNA-Seq, biochemical fractionation\",\n      \"journal\": \"JCI Insight\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — biochemical PTM characterization with multiple pharmacological tools and transcriptomic readout, single lab\",\n      \"pmids\": [\"35819850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The JAG2/Notch1 signaling axis is the primary regulator of sebocyte differentiation in mouse skin; specific inhibition of JAG2 ligand or Notch1 receptor with monoclonal antibodies causes loss of mature sebocytes and accumulation of proliferative stem/progenitor cells, a phenotype that is reversible upon lifting Notch inhibition.\",\n      \"method\": \"Monoclonal therapeutic antibody inhibition of individual Notch ligands/receptors in mice, histology, cell proliferation assays\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — specific ligand/receptor antibody targeting with reversibility demonstrated, strong mechanistic evidence for this specific axis\",\n      \"pmids\": [\"39585329\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Usp11 deubiquitinates JAG2 (and DLL1) to maintain their stability; loss of Usp11 reduces JAG2 ubiquitination, altering Notch signaling in marginal zone B cells and their survival after ionizing radiation.\",\n      \"method\": \"Co-IP and ubiquitination assays in Usp11-/- mice, flow cytometry, histological analysis, single-cell sequencing\",\n      \"journal\": \"Cell Death & Disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP and ubiquitination assay demonstrating deubiquitination of JAG2 by Usp11, with in vivo genetic KO validation\",\n      \"pmids\": [\"39904982\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CD146 activates NF-κB signaling to upregulate JAG2, which then activates Notch signaling to promote stemness and chemoresistance in hepatocellular carcinoma; JAG2 overexpression rescues Notch activity and stemness suppressed by CD146 knockdown.\",\n      \"method\": \"CD146 overexpression/knockdown, JAG2 overexpression rescue experiment, Notch signaling reporter, in vitro self-renewal and chemoresistance assays, xenograft\",\n      \"journal\": \"Cell Death & Disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — epistasis rescue experiment placing JAG2 downstream of CD146/NF-κB in Notch activation, single lab\",\n      \"pmids\": [\"40032820\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Tumor-derived JAG2 activates NOTCH3 on macrophages, inducing STAT3 phosphorylation and CCL2 upregulation, driving an immunosuppressive M2-like, neurotrophic macrophage phenotype that promotes perineural invasion; disruption of JAG2-NOTCH3 signaling, STAT3 inhibition, or CCL2 blockade attenuates invasion in vitro and in vivo.\",\n      \"method\": \"Single-cell transcriptomics, ligand-receptor analysis, STAT3 inhibition, CCL2 neutralization, JAG2 knockdown, xenograft and sciatic nerve invasion models\",\n      \"journal\": \"International Journal of Biological Macromolecules\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mechanistic pathway (JAG2→NOTCH3→STAT3→CCL2) validated by multiple inhibition strategies in vitro and in vivo, single lab\",\n      \"pmids\": [\"41916520\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NEURL1 and NEURL2 (Neuralized-like) ubiquitin ligases do not activate JAG2 because JAG2 lacks the NxxN Neuralized binding motif present in DLL1 and JAG1, establishing differential regulation: NEURL proteins selectively activate only DLL1 and JAG1 among mammalian Notch ligands.\",\n      \"method\": \"Humanized Drosophila system, mammalian cell culture Notch activation assays, motif mutagenesis, comparison across all four mammalian Notch ligands\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution in two systems with motif analysis, but preprint\",\n      \"pmids\": [\"bio_10.1101_2024.09.20.614084\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"JAG2 deficiency and pathogenic JAG2 variants impair Notch signaling and myogenic self-renewal and differentiation in muscle stem cells (MuSCs); MuEC-specific Jag2 knockout reduces MuSC self-renewal (trans-activation), while MuSC-specific Jag2 knockout reduces myogenic differentiation (cis-inhibition); hypomorphic Jag2 mutant mice show depleted MuSCs and impaired muscle regeneration; human reference JAG2 but not pathogenic variants rescues Drosophila Serrate deficiency.\",\n      \"method\": \"Cell-type-specific conditional Jag2 knockout mice, co-culture experiments, Drosophila Serrate rescue with human JAG2 constructs, hypomorphic Jag2 mutant mouse analysis, overexpression of pathogenic variants\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal in vivo genetic and cell biological approaches with cross-species validation, preprint\",\n      \"pmids\": [\"bio_10.1101_2025.07.23.665646\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"JAG2 is a canonical Notch ligand that activates Notch receptors (primarily NOTCH1 and NOTCH2) in trans on neighboring cells to regulate cell fate decisions across multiple tissues—including inner ear hair cells, oral/palatal epithelium, sebaceous gland, skeletal muscle stem cells, and immune cells—while its surface abundance and activity are regulated by posttranslational modifications (including deubiquitination by USP11 and processing by gamma-secretase/GSK3), its transcription is controlled by upstream factors including Myc, DeltaNp63, Wnt/beta-catenin, and HIF-1alpha, and it lacks the NxxN motif required for NEURL-mediated activation, distinguishing it mechanistically from JAG1 and DLL1.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"JAG2 is a transmembrane Notch ligand that activates Notch receptors on neighboring cells to govern binary cell fate decisions across diverse tissues, including inner ear hair cells, oral periderm, sebaceous glands, muscle stem cells, immune cells, and multiple tumor types. JAG2 signals primarily through NOTCH1 to suppress progenitor identity and promote differentiation—exemplified by lateral inhibition of hair cell fate via Math1 repression and HES5 induction in the cochlea [PMID:11545143, PMID:16141228], periderm maturation in oral epithelium [PMID:16607638], and sebocyte differentiation from skin progenitors [PMID:39585329]—and also signals through NOTCH2 and NOTCH3 in context-dependent settings such as nucleus pulposus cell survival [PMID:31619270] and macrophage polarization [PMID:41916520]. Its surface abundance is regulated by USP11-mediated deubiquitination [PMID:39904982] and gamma-secretase/GSK3-dependent processing [PMID:35819850], while its transcription is driven by MYC, ΔNp63, Wnt/β-catenin, HIF-1α, and NF-κB depending on cellular context [PMID:20133585, PMID:17626181, PMID:28881809, PMID:21402725, PMID:40032820]. Biallelic loss-of-function variants in JAG2 cause limb-girdle muscular dystrophy type R27 (LGMD R27), linked to impaired Notch-dependent muscle stem cell self-renewal and myogenesis [PMID:33861953].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Establishing JAG2 as a cochlear Notch ligand that controls hair cell versus supporting cell fate answered the question of which ligand mediates lateral inhibition in the inner ear, revealing that JAG2-dependent Notch activation suppresses Math1 and induces HES5 in cochlear progenitors.\",\n      \"evidence\": \"In situ hybridization of Math1 and HES5 in Jag2-deltaDSL mutant versus wild-type cochleae\",\n      \"pmids\": [\"11545143\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether JAG2 acts alone or redundantly with other ligands in the cochlea was not resolved\", \"Direct receptor identity was not determined\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Demonstrating synergistic action of JAG2 and DLL1 through NOTCH1 in the cochlea resolved the question of ligand redundancy, showing that the two ligands act cooperatively and that the supernumerary hair cell phenotype arises from a cell fate switch rather than excess proliferation.\",\n      \"evidence\": \"Double Dll1/Jag2 knockout mice and conditional Notch1 inactivation with cell fate tracing\",\n      \"pmids\": [\"16141228\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative contribution of each ligand individually was not fully resolved\", \"Whether downstream effectors beyond HES5 differ between JAG2 and DLL1 signaling was not addressed\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identifying JAG2 as overexpressed in myeloma due to promoter hypomethylation and showing that it activates stromal NOTCH1 to induce pro-survival cytokines (IL-6, VEGF, IGF-1) established the first paracrine oncogenic function of JAG2, answering how tumor-stroma Notch signaling supports myeloma growth.\",\n      \"evidence\": \"Anti-Notch-1 antibody blocking in co-culture, methylation analysis of JAG2 promoter in myeloma cells\",\n      \"pmids\": [\"15292061\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether JAG2 signals to other Notch receptors in the myeloma niche was not tested\", \"In vivo relevance in myeloma patients was not demonstrated\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Showing that JAG2 signals through NOTCH1 in oral periderm to prevent premature palatal adhesion established JAG2 as essential for epithelial barrier formation, explaining the cleft palate phenotype of Jag2-null mice.\",\n      \"evidence\": \"Jag2 knockout mice, activated Notch1 immunostaining, recombinant explant co-culture\",\n      \"pmids\": [\"16607638\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether JAG2 controls periderm differentiation cell-autonomously or via juxtacrine signaling was not fully distinguished\", \"Downstream transcriptional targets in periderm were not identified\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Placing ΔNp63 upstream of JAG2 transcription in thymic epithelium answered the question of how p63 regulates γδ T cell development, establishing a ΔNp63→JAG2→Notch transcriptional cascade.\",\n      \"evidence\": \"Genetic complementation of p63-null mice with ΔNp63α transgenes, comparison of p63−/− and Jag2−/− thymic phenotypes\",\n      \"pmids\": [\"17626181\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct p63 binding to the JAG2 promoter was not shown\", \"Whether JAG1 compensates for JAG2 loss in this context was not tested\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrating that loss of SMRT/NCoR2 corepressor causes aberrant JAG2 promoter acetylation and overexpression in myeloma provided an epigenetic mechanism for JAG2 deregulation, complementing the earlier promoter hypomethylation finding.\",\n      \"evidence\": \"Chromatin analysis of JAG2 promoter, SMRT restoration suppressing JAG2 and inducing apoptosis in myeloma cells\",\n      \"pmids\": [\"19417136\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contribution of methylation versus SMRT loss to JAG2 overexpression was not dissected\", \"Whether SMRT directly binds the JAG2 promoter or acts indirectly was not resolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Identifying JAG2 as a direct MYC transcriptional target that drives Notch-dependent tumorigenesis in B cells answered how the MYC oncogene co-opts Notch signaling, establishing a MYC→JAG2→Notch pathway relevant to lymphomagenesis.\",\n      \"evidence\": \"Inducible Myc P493-6 B-cell model, direct Myc ChIP at JAG2 locus, RNAi and gamma-secretase inhibitor treatment in vitro and in vivo\",\n      \"pmids\": [\"20133585\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether JAG2 is the sole mediator of MYC-driven Notch activation was not established\", \"Specific Notch receptor engaged downstream was not identified\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showing that HIF-1α transcriptionally induces JAG2 under hypoxia to elevate Notch activity and promote angiogenesis answered how the tumor microenvironment regulates JAG2 expression, linking oxygen sensing to Notch ligand biology.\",\n      \"evidence\": \"HIF-1α siRNA knockdown, icN1 and HEY1 target gene measurement, co-culture endothelial tube formation assay\",\n      \"pmids\": [\"21402725\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct HIF-1α binding to JAG2 regulatory elements was not mapped\", \"Whether JAG2-mediated angiogenesis requires cell contact or is exosome-mediated was not tested\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Placing JAG2 downstream of Wnt/β-catenin signaling and upstream of p21-mediated chemoresistance in colorectal cancer answered how JAG2 integrates Wnt and Notch pathways to promote treatment resistance.\",\n      \"evidence\": \"APC conditional knockout mice, β-catenin knockdown, p21 forced expression rescue of JAG2-knockdown sensitivity\",\n      \"pmids\": [\"28881809\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether JAG2 directly transcriptionally regulates p21 or acts through Notch/HES was not shown\", \"Relevance to patient chemotherapy response was not validated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identifying biallelic JAG2 variants as the cause of LGMD R27 answered whether JAG2 is essential for human skeletal muscle maintenance, establishing that Notch pathway dysfunction in muscle stem cells underlies a progressive muscular dystrophy.\",\n      \"evidence\": \"Whole-exome sequencing in families, muscle transcriptome showing PAX7 and myogenesis gene misregulation, Jag2 siRNA in murine myoblasts, Drosophila Serrate/Draper genetic interaction\",\n      \"pmids\": [\"33861953\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cell-type-specific (MuSC vs. MuEC) contributions of JAG2 to disease were not dissected\", \"Whether disease variants are loss-of-function or dominant-negative was not fully resolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Demonstrating that gamma-secretase and GSK3 regulate full-length JAG2 surface abundance in airway epithelium answered how posttranslational processing controls JAG2-mediated Notch signal strength to determine goblet versus ciliated cell fate.\",\n      \"evidence\": \"Human air-liquid interface cultures, gamma-secretase inhibitors, neutralizing antibodies, RNA-Seq, biochemical fractionation\",\n      \"pmids\": [\"35819850\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific GSK3 phosphorylation sites on JAG2 were not mapped\", \"Whether this processing mechanism operates in non-airway tissues was not tested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Specific antibody-mediated blockade of JAG2 or NOTCH1 causing reversible loss of mature sebocytes established the JAG2/Notch1 axis as the primary differentiation signal in the sebaceous gland, answering which ligand-receptor pair drives this lineage.\",\n      \"evidence\": \"Monoclonal antibody inhibition of individual Notch ligands and receptors in mice, histology, cell proliferation assays, reversibility upon withdrawal\",\n      \"pmids\": [\"39585329\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream transcription factors activated by JAG2/Notch1 in sebocytes were not identified\", \"Human sebaceous gland relevance was not directly shown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery that USP11 deubiquitinates JAG2 to maintain its stability answered how JAG2 protein turnover is regulated, revealing that ubiquitin-dependent degradation controls JAG2-mediated Notch signaling in marginal zone B cells.\",\n      \"evidence\": \"Co-IP and ubiquitination assays in Usp11−/− mice, flow cytometry of B cell subsets\",\n      \"pmids\": [\"39904982\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific ubiquitin chain types on JAG2 were not characterized\", \"Whether other deubiquitinases compensate for USP11 was not tested\", \"Reciprocal validation (e.g., JAG2 pulldown of USP11) not explicitly described\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showing that tumor-derived JAG2 activates NOTCH3/STAT3/CCL2 on macrophages to create an immunosuppressive niche promoting perineural invasion answered how JAG2 shapes the tumor immune microenvironment beyond direct tumor cell effects.\",\n      \"evidence\": \"Single-cell transcriptomics, ligand-receptor analysis, STAT3 inhibition, CCL2 neutralization, JAG2 knockdown, xenograft and sciatic nerve invasion models\",\n      \"pmids\": [\"41916520\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether this JAG2-NOTCH3 axis operates in other tumor types was not tested\", \"Structural basis for JAG2 selectivity for NOTCH3 versus NOTCH1 was not addressed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key open questions include the structural determinants of JAG2 receptor selectivity (NOTCH1 vs. NOTCH2 vs. NOTCH3), the identity of E3 ubiquitin ligases that target JAG2 for degradation (given its insensitivity to NEURL), and whether JAG2's cis-inhibitory and trans-activating functions are structurally separable.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal structure of JAG2-Notch complex exists\", \"E3 ligase(s) targeting JAG2 for ubiquitination are unknown\", \"Relative contribution of cis-inhibition versus trans-activation in muscle stem cell biology requires further dissection\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [0, 1, 2, 3, 6, 13, 18, 21]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 2, 3, 18]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [17, 19]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 2, 3, 6, 13, 18, 21]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 1, 3, 4, 15, 18, 23]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2, 5, 6, 8, 9, 10, 11, 14, 20, 21]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [4, 12, 21]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"NOTCH1\",\n      \"NOTCH2\",\n      \"NOTCH3\",\n      \"USP11\",\n      \"DLL1\",\n      \"PRAF2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}