{"gene":"KMT5C","run_date":"2026-06-10T02:59:49","timeline":{"discoveries":[{"year":2013,"finding":"SUV420H2 (KMT5C) stably associates with pericentric heterochromatin through synergistic interactions with multiple HP1 molecules, mediating chromatin compaction. Cohesin subunits interact with SUV420H2 both in vitro and in vivo, and this interaction is necessary for cohesin binding to heterochromatin. SUV420H2-deficient cells display reduced sister chromatid cohesion and chromosome segregation defects during mitosis.","method":"Tandem affinity purification, Co-IP (in vivo and in vitro), FRAP, immunofluorescence, Suv4-20h mutant cell analysis","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP in vitro and in vivo, functional KO phenotype with multiple orthogonal readouts (cohesion, segregation, chromatin compaction), replicated across conditions","pmids":["23599346"],"is_preprint":false},{"year":2009,"finding":"SUV420H2 interacts with HP1 proteins (identified as main partners by TAP-MS), with the interaction mapped to the heterochromatic targeting module (HTM) of SUV420H2 and the HP1 chromoshadow domain. FRAP reveals that SUV420H2 is strongly and stably bound to pericentric heterochromatin (in contrast to highly mobile HP1), and an 88 amino-acid HTM region recapitulates both HP1 binding and stable heterochromatin association.","method":"Tandem affinity purification/mass spectrometry (TAP-MS), FRAP, immunofluorescence, domain mapping","journal":"BMC cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — TAP-MS plus FRAP plus domain mapping in single study with multiple orthogonal methods","pmids":["19486527"],"is_preprint":false},{"year":2013,"finding":"Crystal structures of human SUV420H2 (and SUV420H1) in complex with SAM were solved at high resolution. Both enzymes have a unique N-terminal domain and Zn-binding post-SET domain, and prefer monomethylated H4K20 as substrate in vitro. No H4K20 trimethylation activity was detected for either enzyme in a radioactivity-based assay, consistent with a conserved serine residue that forms a hydrogen bond with the target lysine side-chain and limits methylation level.","method":"X-ray crystallography, in vitro radioactivity-based methyltransferase assay, substrate specificity analysis","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus in vitro enzymatic assay with substrate specificity, rigorous controls, single study","pmids":["24396869"],"is_preprint":false},{"year":2011,"finding":"SUV420H2-mediated H4K20me3 antagonizes hMOF-mediated H4K16 acetylation at gene promoters, blocking RNA Polymerase II escape from promoter-proximal pausing. Combined inhibition of H4K20me3 and DNA methylation allowed hMOF re-recruitment, H4K16Ac restoration, Pol II release into elongation, and reactivation of TMS1/ASC expression.","method":"ChIP, siRNA knockdown, pharmacological inhibition of DNA methylation, Pol II pausing assays, gene expression analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — ChIP with multiple histone marks, epistatic rescue experiment, and functional Pol II elongation assay in single study","pmids":["21321083"],"is_preprint":false},{"year":2016,"finding":"By in vitro methylation studies and SPOT peptide arrays, SUV420H2 strongly favors monomethylated H4K20 as substrate and generates only dimethylated H4K20 product. SUV420H2 recognition motif is X-Kme1-(IVLMK)-(LVFI)-X-(DEV), with relaxed specificity compared to SUV420H1. Novel non-histone substrates were identified: K1423 of Zinc finger protein castor homolog 1, K215 of Protein Mis18-beta, and K308 of Centromere protein U.","method":"In vitro methylation assay, SPOT peptide array substrate specificity mapping","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic reconstitution with systematic substrate specificity arrays, single rigorous study","pmids":["27105552"],"is_preprint":false},{"year":2017,"finding":"QM/MM simulations demonstrated that Suv4-20h2 (KMT5C) generates dimethylated H4K20 from monomethylated substrate due to effective transition state stabilization via CH···O interactions and a cation-π interaction. The enzyme fails to catalyze monomethylation (less effective TS stabilization) and trimethylation (H4K20me2-containing reactant complex cannot adopt a reactive near-attack configuration for methyl transfer).","method":"QM/MM molecular dynamics and free energy (potential of mean force) simulations","journal":"Journal of chemical theory and computation","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — rigorous computational mechanistic analysis but no experimental mutagenesis validation; single study","pmids":["28489369"],"is_preprint":false},{"year":2015,"finding":"Exogenous delivery of SUV420H2 into MDA-MB-231 breast cancer cells induced selective downregulation of tensin-3 (a focal adhesion protein promoting cancer cell migration), associated with enrichment of H4K20me3 immediately upstream of the tensin-3 transcription start site. Depletion of tensin-3 suppressed breast cancer cell invasiveness, connecting SUV420H2/H4K20me3 loss to upregulation of cancer-promoting genes and invasion.","method":"Exogenous gene delivery, RNA-seq, ChIP (H4K20me3), siRNA knockdown, invasion assay","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP linking H4K20me3 to tensin-3 promoter and functional invasion rescue, single lab with two orthogonal approaches","pmids":["25814362"],"is_preprint":false},{"year":2017,"finding":"SUV420H2 (KMT5C) represses epithelial gene expression through H4K20me3, thereby favoring the mesenchymal identity in pancreatic cancer. SUV420H2 knockdown elicited mesenchymal-to-epithelial transition, decreased stemness, and increased drug sensitivity in pancreatic cancer cell lines.","method":"siRNA knockdown, gene expression profiling, functional assays (EMT markers, stemness, drug sensitivity)","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KD with defined molecular and functional EMT phenotype, multiple readouts, single lab","pmids":["29229751"],"is_preprint":false},{"year":2010,"finding":"SUV420H2 localizes preferentially to constitutive (pericentric) heterochromatin, and co-expression with HP1α increased its targeting to pericentromeric regions. SUV420H2 facilitated an increase in pericentric H4K20me3 and maintained a Myogenin-enriched population during myogenic differentiation in C2C12 cells, acting as an epigenetic switch for myogenesis.","method":"Immunofluorescence, gain-of-function expression, C2C12 myogenic differentiation assay, HP1α co-expression","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — immunofluorescence localization plus functional differentiation assay, multiple conditions tested, single lab","pmids":["21206904"],"is_preprint":false},{"year":2020,"finding":"SUV420H2 depletion in embryonic stem (ES) cells leads to near-complete loss of H4K20me3 genome-wide, dysregulated gene expression, and delayed ES cell differentiation. SUV420H2-bound regions are enriched at repetitive DNA elements which become de-repressed upon knockout. Loss of SUV420H2 results in A/B compartment switching, perturbed chromatin insulation, and altered chromatin interactions of pericentric heterochromatin, indicating a role in 3D chromatin architecture.","method":"SUV420H2 knockout, ChIP-seq, RNA-seq, Hi-C, ChIP for H4K20me3","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic KO with multiple genome-wide orthogonal methods (ChIP-seq, RNA-seq, Hi-C) in single rigorous study","pmids":["33144397"],"is_preprint":false},{"year":2020,"finding":"KMT5C expression is induced by β3-adrenergic signaling in brown and beige fat. Adipocyte-specific KMT5C knockout leads to decreased thermogenic gene expression, susceptibility to diet-induced obesity, and glucose intolerance. Mechanistically, increased Trp53 (p53) expression due to decreased H4K20me3 on its proximal promoter is responsible for the metabolic phenotypes in KMT5C KO mice.","method":"Adipocyte-specific KO mice, ChIP (H4K20me3 at Trp53 promoter), gene expression analysis, metabolic phenotyping","journal":"PNAS","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vivo KO with ChIP linking H4K20me3 to Trp53 promoter repression, rescue experiments, multiple metabolic readouts","pmids":["32839323"],"is_preprint":false},{"year":2022,"finding":"Loss of KMT5C in NSCLC cells drives resistance to multiple EGFR inhibitors by upregulating the long noncoding RNA LINC01510, which promotes transcription of the oncogene MET, activating a bypass signaling mechanism. KMT5C catalyzes H4K20me3 required for repression of LINC01510.","method":"KMT5C knockdown/knockout, gene expression analysis, ChIP (H4K20me3), LINC01510 overexpression rescue, in vitro and in vivo drug resistance assays","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP linking H4K20me3 to LINC01510 locus, functional rescue, mechanistic pathway placement, single lab","pmids":["35404406"],"is_preprint":false},{"year":2021,"finding":"Upon influenza virus infection, the viral nucleoprotein (NP) binds Suv4-20h2, inactivating it and causing dissociation of cohesin from Suv4-20h2. This inactivation allows cohesin-mediated chromatin loop formation at HoxC8-HoxC6 loci, upregulating HoxC8 and HoxC6, which enhance viral replication by inhibiting Wnt-β-catenin-mediated interferon response.","method":"Co-IP (NP-Suv4-20h2 interaction), genetic deletion of Suv4-20h2, chromatin conformation analysis, in vivo influenza infection model","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifying viral NP as binding partner, genetic KO with functional chromatin loop and antiviral pathway readouts, single lab","pmids":["34169237"],"is_preprint":false},{"year":2022,"finding":"Suv4-20h2-mediated H4K20me3 is required for maintaining heterochromatin compaction in intestinal organoids and to prevent R-loop formation. Loss of Suv4-20h2 in right-sided colorectal cancer is associated with increased chromatin accessibility, stemness/Wnt signaling, and drives tumor progression; re-compaction with a histone demethylase inhibitor selectively reduced growth of right-sided cancer-derived tumors.","method":"Patient-derived organoids, mouse intestinal organoids, genetic manipulation, MNase assay, ChIP, gene expression profiling, xenograft transplantation","journal":"Gastroenterology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — MNase assay for chromatin compaction, ChIP, R-loop detection, and in vivo xenograft in single rigorous study with multiple orthogonal methods","pmids":["36402192"],"is_preprint":false},{"year":2023,"finding":"KMT5C (SUV420H2) interacts with RAD51 and promotes RAD51/RAD54 complex formation, activating double-strand break repair by homologous recombination. This function depends on KMT5C methyltransferase activity. KMT5C knockdown or pharmacological inhibition with A196 sensitizes liver cancer cells to PARP inhibitors.","method":"Co-IP (KMT5C-RAD51), RAD51/RAD54 complex analysis, methyltransferase inhibitor (A196) treatment, KMT5C knockdown, DNA repair assays, xenograft models","journal":"Hepatology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP identifying RAD51 as interacting partner, methyltransferase-activity-dependent functional requirement, functional drug synergy, single lab","pmids":["37556368"],"is_preprint":false},{"year":2024,"finding":"KMT5C heterochromatin retention is conferred by two HP1-interaction modules in the HTM, tethered by an intrinsically disordered linker. The first module uses adjacent sequences for avidity-based HP1 binding; the second increases HP1 effective concentration. FRAP reveals KMT5C undergoes rapid internal diffusion but minimal nucleoplasmic exchange. The linker is under evolutionary constraint for functional length, enabling cooperativity between modules across orthologs.","method":"FRAP, domain mutagenesis, heterologous linker experiments, heterochromatin recruitment assays","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — FRAP plus systematic domain mutagenesis plus heterologous linker experiments, multiple orthogonal approaches in single rigorous study","pmids":["39562713"],"is_preprint":false},{"year":2024,"finding":"Three HP1-binding motifs were identified within the SUV420H2 HTM. The HTM N-terminal region (containing first and second motifs) stabilizes HP1 on heterochromatin. The HTM C-terminal region (third motif) destabilizes HP1 on chromatin. An HTM V374D mutant (Val374→Asp in the second HP1 binding motif) localizes to heterochromatin without affecting HP1 stability, demonstrating the second motif is critical for locking HP1 on H3K9me3-enriched heterochromatin.","method":"Domain mapping, point mutagenesis (V374D), live-cell fluorescence imaging, HP1 stability assays","journal":"Genes to cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mutagenesis plus live-cell imaging, mechanistic dissection of HP1 binding motifs, single lab","pmids":["38403935"],"is_preprint":false},{"year":2025,"finding":"KMT5C regulates hepatic gluconeogenesis through a non-catalytic mechanism: it impedes the E3 ligase RNF34 from binding the C-terminal of PGC-1α, thereby blocking ubiquitination-mediated PGC-1α degradation and maintaining gluconeogenic gene expression. This function is independent of KMT5C methyltransferase activity.","method":"Hepatocyte-specific KO mice, Co-IP (KMT5C-RNF34-PGC-1α), ubiquitination assay, methyltransferase-inactive mutant, gluconeogenesis and glucose output assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — Co-IP identifying RNF34 and PGC-1α as partners, catalytic mutant establishing non-enzymatic mechanism, in vivo KO with metabolic phenotype, multiple orthogonal methods","pmids":["39929827"],"is_preprint":false},{"year":2024,"finding":"SUV420H2 (Suv420h2) catalyzes H4K20 trimethylation at the 4e-bp1 promoter, leading to downregulated expression of 4E-BP1 (a negative regulator of translation initiation), which in turn increases PGC1α protein levels and thermogenic gene expression in brown/beige adipocytes.","method":"Suv420h2 KO and adipocyte-specific overexpression mice, ChIP (H4K20me3 at 4e-bp1 promoter), gene and protein expression analysis, cold tolerance and obesity phenotyping","journal":"JCI insight","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP linking H4K20me3 to 4e-bp1 promoter, in vivo KO and OE with functional thermogenic phenotype, single lab","pmids":["38713533"],"is_preprint":false},{"year":2025,"finding":"KMT5C activates the DNA repair response and inhibits the STING-IRF3 pathway and downstream type I IFN signaling in NSCLC, reducing CCL5 secretion and CD8+ T cell infiltration, thereby facilitating tumor immune evasion. Pharmacological inhibition (A196) or genetic inhibition of KMT5C synergizes with anti-PD-1 therapy.","method":"KMT5C knockdown/inhibition, STING-IRF3 pathway assays, cytokine measurement, immune cell profiling, in vivo mouse lung cancer models with anti-PD-1 combination","journal":"Advanced science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic and pharmacological KD with defined immunological pathway readouts, in vivo combination therapy, single lab","pmids":["40126333"],"is_preprint":false},{"year":2023,"finding":"SUV420H2 (KMT5C) epigenetically silences DHRS2 through H4K20me3 deposition at its promoter in renal cell carcinoma. SUV420H2 knockdown leads to DHRS2 upregulation and cell apoptosis; co-knockdown of DHRS2 attenuates this effect, placing SUV420H2-mediated H4K20me3 upstream of DHRS2-dependent cell survival.","method":"siRNA knockdown, ChIP (H4K20me3 at DHRS2 promoter), rescue co-knockdown, A-196 inhibitor treatment, cell viability/apoptosis assays","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP linking H4K20me3 to DHRS2 promoter, epistatic rescue experiment, single lab","pmids":["37119764"],"is_preprint":false},{"year":2025,"finding":"KMT5C suppresses OSCC progression by epigenetically silencing UPP1 via H4K20me3 deposition at the UPP1 promoter. Transcription factor NR2C2 is responsible for recruiting KMT5C to the UPP1 promoter to achieve this H4K20me3 modification and transcriptional inhibition.","method":"KMT5C overexpression and knockdown, ChIP (H4K20me3 at UPP1 promoter), NR2C2 interaction/recruitment assay, in vitro and in vivo functional assays","journal":"Laboratory investigation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP linking H4K20me3 to UPP1 promoter, NR2C2 recruitment mechanism, single lab with multiple orthogonal methods","pmids":["39954852"],"is_preprint":false},{"year":2016,"finding":"Suv420h2 loss-of-function (siRNA depletion) in osteoblast precursors results in loss of H4K20 methylation and decreased expression of osteogenic biomarkers (alkaline phosphatase/Alpl) and transcription factors (Sp7/Osterix), and impairs matrix mineralization, establishing Suv420h2 as required for normal osteoblast differentiation progression.","method":"siRNA knockdown, H4K20 methylation assay, gene expression analysis, alkaline phosphatase/mineralization assays","journal":"Journal of cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — KD with defined molecular and functional osteoblast differentiation phenotype, multiple markers, single lab","pmids":["27862226"],"is_preprint":false},{"year":2026,"finding":"KMT5C deposits H4K20me3 in a non-canonical manner, independent of H3K9me3 (previously considered a prerequisite). This non-canonical H4K20me3 lacks canonical repressive epigenetic signatures and instead overlaps with activating marks. ZNF280C was identified as a novel KMT5C-interacting partner localizing specifically at H3K9me3-/H4K20me3+ sites, mediating HP1-independent recruitment of KMT5C to these loci.","method":"ChIP-seq (H4K20me3, H3K9me3, activating marks), biochemical pulldown/Co-IP (KMT5C-ZNF280C), RNA-seq upon KMT5C loss","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — ChIP-seq and biochemical Co-IP identifying ZNF280C, preprint not yet peer-reviewed, single lab","pmids":["42182233"],"is_preprint":true}],"current_model":"KMT5C (SUV420H2) is a lysine methyltransferase that preferentially converts monomethylated H4K20 to the di- and trimethylated states (H4K20me2/3), targeting pericentric heterochromatin through cooperative binding to HP1 proteins via multiple interaction motifs in its heterochromatic targeting module; H4K20me3 deposited by KMT5C maintains chromatin compaction, recruits cohesin to heterochromatin (required for sister chromatid cohesion and chromosome segregation), represses repetitive elements and gene transcription by antagonizing H4K16 acetylation and blocking RNA Pol II elongation, and regulates 3D chromatin architecture; beyond canonical heterochromatin, KMT5C also deposits H4K20me3 at non-canonical loci via ZNF280C and exerts non-catalytic functions (e.g., stabilizing PGC-1α by blocking RNF34-mediated ubiquitination) and interacts with RAD51 to promote homologous recombination repair, collectively making KMT5C a multifunctional epigenetic regulator of genome integrity, gene expression, differentiation, metabolism, and immune signaling."},"narrative":{"mechanistic_narrative":"KMT5C (SUV420H2) is a SAM-dependent lysine methyltransferase that deposits di- and trimethylated H4K20 (H4K20me2/3) to establish and maintain repressive heterochromatin, thereby controlling genome integrity, gene expression, differentiation, and metabolism [PMID:23599346, PMID:24396869]. Structurally it carries a unique N-terminal domain and a Zn-binding post-SET domain, prefers monomethylated H4K20 as substrate, and is intrinsically limited to producing dimethyl product by a conserved serine that hydrogen-bonds the target lysine, with transition-state geometry favoring H4K20me2 over me1 or me3 [PMID:24396869, PMID:27105552, PMID:28489369]. The enzyme is stably retained at pericentric heterochromatin through a heterochromatic targeting module that engages the HP1 chromoshadow domain; this module contains multiple HP1-binding motifs tethered by a length-constrained intrinsically disordered linker that confers avidity-based, cooperative HP1 locking on H3K9me3 chromatin [PMID:19486527, PMID:39562713, PMID:38403935]. At heterochromatin, KMT5C-generated H4K20me3 maintains chromatin compaction, recruits cohesin to enable sister chromatid cohesion and accurate chromosome segregation, organizes 3D chromatin architecture, and represses repetitive elements [PMID:23599346, PMID:33144397]. It silences specific gene promoters by antagonizing hMOF-mediated H4K16 acetylation and blocking RNA Pol II escape from promoter-proximal pausing [PMID:21321083]. KMT5C acts as an epigenetic switch in cell-fate programs including myogenic and osteoblast differentiation [PMID:21206904, PMID:27862226], and controls thermogenic and gluconeogenic metabolism both catalytically — repressing Trp53 and 4e-bp1 promoters in adipocytes [PMID:32839323, PMID:38713533] — and non-catalytically, by shielding PGC-1α from RNF34-mediated ubiquitination [PMID:39929827]. In cancer, loss of KMT5C-dependent H4K20me3 de-represses pro-tumorigenic loci and influences EMT, invasion, drug resistance, and immune evasion, while its methyltransferase activity additionally promotes RAD51/RAD54-mediated homologous recombination repair [PMID:36402192, PMID:37556368, PMID:40126333]. Beyond canonical heterochromatin, KMT5C can deposit H4K20me3 at H3K9me3-negative loci via the partner ZNF280C, indicating an HP1-independent targeting route [PMID:42182233].","teleology":[{"year":2009,"claim":"Established how KMT5C is anchored to heterochromatin, answering what tethers the enzyme stably to its site of action.","evidence":"TAP-MS, FRAP and domain mapping identifying HP1 binding via an 88-aa heterochromatic targeting module","pmids":["19486527"],"confidence":"High","gaps":["Did not resolve the stoichiometry or cooperativity of HP1 engagement","No structural model of the HTM-HP1 interface"]},{"year":2010,"claim":"Connected KMT5C heterochromatin targeting to a cell-fate decision, showing it functions as an epigenetic switch in differentiation.","evidence":"Immunofluorescence, HP1α co-expression and C2C12 myogenic differentiation assays","pmids":["21206904"],"confidence":"Medium","gaps":["Gain-of-function only; loss-of-function not tested here","Target genes driving the myogenic switch not defined"]},{"year":2011,"claim":"Defined a mechanism of gene repression, showing H4K20me3 antagonizes H4K16 acetylation to control transcription elongation.","evidence":"ChIP for multiple histone marks, siRNA, DNA-methylation inhibition and Pol II pausing assays with epistatic rescue","pmids":["21321083"],"confidence":"High","gaps":["Mechanism by which H4K20me3 excludes hMOF not resolved","Generality across loci untested in this study"]},{"year":2013,"claim":"Revealed a structural role for KMT5C in mitotic chromosome biology by linking it physically and functionally to cohesin loading at heterochromatin.","evidence":"Tandem affinity purification, reciprocal Co-IP in vitro and in vivo, FRAP, and Suv4-20h KO phenotyping of cohesion and segregation","pmids":["23599346"],"confidence":"High","gaps":["Whether cohesin recruitment requires catalytic H4K20me3 or scaffolding alone not separated","Direct cohesin-binding interface not mapped"]},{"year":2013,"claim":"Provided the structural and biochemical basis for KMT5C's product specificity, explaining why it stops at H4K20me2 in vitro.","evidence":"X-ray crystallography of SUV420H2-SAM and in vitro radioactivity-based methyltransferase assays","pmids":["24396869"],"confidence":"High","gaps":["Apparent me2-only ceiling in vitro is hard to reconcile with H4K20me3 deposition in cells","No structure of an enzyme-nucleosome complex"]},{"year":2016,"claim":"Extended KMT5C activity beyond histones by defining its recognition motif and identifying non-histone substrates.","evidence":"In vitro methylation assays and SPOT peptide array substrate-specificity mapping","pmids":["27105552"],"confidence":"High","gaps":["Non-histone substrate methylation not validated in cells","Functional consequence of CASZ1/MIS18B/CENPU methylation unknown"]},{"year":2016,"claim":"Established KMT5C as required for osteoblast differentiation, broadening its role across cell-lineage programs.","evidence":"siRNA knockdown with H4K20 methylation, osteogenic marker expression and mineralization assays","pmids":["27862226"],"confidence":"Medium","gaps":["Direct gene targets in osteoblasts not identified","siRNA only; no genetic or in vivo confirmation"]},{"year":2017,"claim":"Provided a computational mechanistic explanation for KMT5C's dimethyl product specificity at the transition-state level.","evidence":"QM/MM molecular dynamics and free-energy (potential of mean force) simulations","pmids":["28489369"],"confidence":"Medium","gaps":["No experimental mutagenesis validation of predicted catalytic determinants","Does not address in vivo H4K20me3"]},{"year":2017,"claim":"Linked KMT5C-mediated repression to cancer cell identity, showing it enforces mesenchymal state and stemness.","evidence":"siRNA knockdown with EMT-marker, stemness and drug-sensitivity profiling in pancreatic cancer lines","pmids":["29229751"],"confidence":"Medium","gaps":["Specific repressed epithelial gene targets not enumerated","Knockdown only; no in vivo validation"]},{"year":2020,"claim":"Demonstrated genome-wide that KMT5C is the principal H4K20me3 writer controlling repeat silencing and 3D chromatin architecture.","evidence":"ESC knockout with ChIP-seq, RNA-seq and Hi-C","pmids":["33144397"],"confidence":"High","gaps":["Causal link between compartment switching and transcriptional changes not dissected","Mechanism of repeat de-repression beyond H4K20me3 loss unresolved"]},{"year":2020,"claim":"Established a physiological metabolic role, showing KMT5C represses Trp53 to enable adipose thermogenesis.","evidence":"Adipocyte-specific KO mice with ChIP at the Trp53 promoter and metabolic phenotyping","pmids":["32839323"],"confidence":"High","gaps":["How β3-adrenergic signaling induces KMT5C transcription not defined","Whether other adipose targets contribute not addressed"]},{"year":2021,"claim":"Revealed KMT5C as a target of viral subversion, where influenza NP inactivates it to release cohesin and reprogram chromatin loops.","evidence":"Co-IP of NP-Suv4-20h2, Suv4-20h2 deletion, chromatin conformation analysis and in vivo infection","pmids":["34169237"],"confidence":"Medium","gaps":["Molecular basis of NP-mediated inactivation not defined","Single-lab finding without independent confirmation"]},{"year":2022,"claim":"Connected loss of KMT5C-dependent repression to targeted-therapy resistance via lncRNA-driven bypass signaling.","evidence":"KMT5C knockdown/KO, ChIP at LINC01510, LINC01510 rescue, and drug-resistance assays in NSCLC","pmids":["35404406"],"confidence":"Medium","gaps":["Mechanism linking LINC01510 to MET transcription not fully resolved","Single-lab finding"]},{"year":2022,"claim":"Tied KMT5C-maintained heterochromatin compaction to genome stability and tumor suppression in the intestine.","evidence":"Patient-derived and mouse organoids, MNase compaction assay, ChIP, R-loop detection and xenografts","pmids":["36402192"],"confidence":"High","gaps":["How H4K20me3 loss promotes R-loops mechanistically unclear","Right-sided specificity determinants not defined"]},{"year":2023,"claim":"Identified a catalytic role for KMT5C in DNA repair by promoting RAD51/RAD54 complex formation during homologous recombination.","evidence":"Co-IP of KMT5C-RAD51, complex-formation analysis, methyltransferase inhibitor A196, knockdown and xenografts","pmids":["37556368"],"confidence":"Medium","gaps":["The relevant methylation substrate in HR not identified","Single Co-IP-based interaction without reciprocal structural mapping"]},{"year":2023,"claim":"Added a cancer-survival target gene, placing KMT5C-mediated H4K20me3 upstream of DHRS2-dependent apoptosis control.","evidence":"siRNA knockdown, ChIP at DHRS2 promoter, epistatic co-knockdown rescue and A-196 treatment in RCC","pmids":["37119764"],"confidence":"Medium","gaps":["Recruitment mechanism to the DHRS2 locus unknown","Single-lab finding"]},{"year":2024,"claim":"Resolved the biophysical logic of heterochromatin retention, showing two HP1 modules joined by a length-constrained disordered linker confer cooperative binding.","evidence":"FRAP, domain mutagenesis and heterologous linker swaps in recruitment assays","pmids":["39562713"],"confidence":"High","gaps":["Atomic structure of the two-module-HP1 assembly not determined","How retention couples to catalytic turnover unaddressed"]},{"year":2024,"claim":"Dissected the individual HP1-binding motifs, defining one motif as critical for locking HP1 onto H3K9me3 heterochromatin.","evidence":"Domain mapping, V374D point mutagenesis and live-cell imaging with HP1 stability assays","pmids":["38403935"],"confidence":"Medium","gaps":["Functional consequence of HP1 stabilization vs destabilization for catalysis not tested","Single-lab finding"]},{"year":2024,"claim":"Extended adipose regulation, showing KMT5C-dependent repression of 4e-bp1 raises PGC1α protein and thermogenic output.","evidence":"Suv420h2 KO and adipocyte-specific overexpression mice, ChIP at the 4e-bp1 promoter and thermogenic phenotyping","pmids":["38713533"],"confidence":"Medium","gaps":["Reported H4K20me3 at 4e-bp1 vs in vitro me2-only ceiling not reconciled","Single-lab finding"]},{"year":2025,"claim":"Established a methyltransferase-independent function, showing KMT5C scaffolds PGC-1α stability by blocking RNF34-mediated ubiquitination in liver.","evidence":"Hepatocyte-specific KO mice, Co-IP of KMT5C-RNF34-PGC-1α, ubiquitination assays and a catalytically inactive mutant","pmids":["39929827"],"confidence":"High","gaps":["Structural basis of the KMT5C-RNF34 competition not resolved","Generality of non-catalytic scaffolding to other tissues untested"]},{"year":2025,"claim":"Linked KMT5C to tumor immune evasion via suppression of STING-IRF3/type I IFN signaling and reduced CD8+ T cell infiltration.","evidence":"KMT5C knockdown/inhibition, STING-IRF3 and cytokine assays, immune profiling and anti-PD-1 combination in vivo","pmids":["40126333"],"confidence":"Medium","gaps":["Whether immune suppression is catalytic or via DNA-repair-mediated cGAS-STING attenuation not separated","Single-lab finding"]},{"year":2025,"claim":"Added a transcription-factor-directed recruitment route, with NR2C2 bringing KMT5C to the UPP1 promoter to suppress OSCC.","evidence":"KMT5C overexpression/knockdown, ChIP at UPP1, NR2C2 recruitment assays and in vitro/in vivo functional tests","pmids":["39954852"],"confidence":"Medium","gaps":["Direct KMT5C-NR2C2 interaction interface not mapped","Single-lab finding"]},{"year":2026,"claim":"Challenged the H3K9me3-prerequisite model, showing KMT5C can deposit non-canonical H4K20me3 at activating-mark loci via ZNF280C, independent of HP1.","evidence":"ChIP-seq of H4K20me3/H3K9me3/activating marks, Co-IP of KMT5C-ZNF280C and RNA-seq (preprint)","pmids":["42182233"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Functional role of non-canonical H4K20me3 at active loci undefined","ZNF280C recruitment mechanism not resolved"]},{"year":null,"claim":"It remains unresolved how KMT5C achieves H4K20 trimethylation in cells given the in vitro and computational evidence that the isolated enzyme stops at the dimethyl product.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No cofactor, partner, or chromatin-context determinant identified that enables H4K20me3 deposition","No structure of KMT5C on a nucleosome substrate","Discrepancy between cellular H4K20me3 ChIP and in vitro me2-only activity unexplained"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[2,4,0]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[2,4]},{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[1,16]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[3,9,10]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,1,8]},{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[0,1,8,9]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[0,3,9]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[3,9,10]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[0]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[14]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[8,9,22]},{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[10,17,18]}],"complexes":["pericentric heterochromatin"],"partners":["CBX5","RAD51","RAD54","RNF34","PPARGC1A","ZNF280C","NR2C2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q86Y97","full_name":"Histone-lysine N-methyltransferase KMT5C","aliases":["Lysine N-methyltransferase 5C","Lysine-specific methyltransferase 5C","Suppressor of variegation 4-20 homolog 2","Su(var)4-20 homolog 2","Suv4-20h2","[histone H4]-N-methyl-L-lysine20 N-methyltransferase KMT5B","[histone H4]-lysine20 N-methyltransferase KMT5B"],"length_aa":462,"mass_kda":52.1,"function":"Histone methyltransferase that specifically methylates monomethylated 'Lys-20' (H4K20me1) and dimethylated 'Lys-20' (H4K20me2) of histone H4 to produce respectively dimethylated 'Lys-20' (H4K20me2) and trimethylated 'Lys-20' (H4K20me3) and thus regulates transcription and maintenance of genome integrity (PubMed:24396869, PubMed:28114273). In vitro also methylates unmodified 'Lys-20' (H4K20me0) of histone H4 and nucleosomes (PubMed:24396869). H4 'Lys-20' trimethylation represents a specific tag for epigenetic transcriptional repression. Mainly functions in pericentric heterochromatin regions, thereby playing a central role in the establishment of constitutive heterochromatin in these regions. KMT5C is targeted to histone H3 via its interaction with RB1 family proteins (RB1, RBL1 and RBL2) (By similarity). Facilitates TP53BP1 foci formation upon DNA damage and proficient non-homologous end-joining (NHEJ)-directed DNA repair by catalyzing the di- and trimethylation of 'Lys-20' of histone H4 (PubMed:28114273). May play a role in class switch reconbination by catalyzing the di- and trimethylation of 'Lys-20' of histone H4 (By similarity)","subcellular_location":"Nucleus; Chromosome","url":"https://www.uniprot.org/uniprotkb/Q86Y97/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KMT5C","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":[],"url":"https://opencell.sf.czbiohub.org/search/KMT5C","total_profiled":1310},"omim":[{"mim_id":"620055","title":"PWP1 HOMOLOG, ENDONUCLEIN; PWP1","url":"https://www.omim.org/entry/620055"},{"mim_id":"613198","title":"LYSINE METHYLTRANSFERASE 5C; KMT5C","url":"https://www.omim.org/entry/613198"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/KMT5C"},"hgnc":{"alias_symbol":["MGC2705"],"prev_symbol":["SUV420H2"]},"alphafold":{"accession":"Q86Y97","domains":[{"cath_id":"2.170.270.10","chopping":"9-243","consensus_level":"medium","plddt":93.068,"start":9,"end":243}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86Y97","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q86Y97-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q86Y97-F1-predicted_aligned_error_v6.png","plddt_mean":68.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KMT5C","jax_strain_url":"https://www.jax.org/strain/search?query=KMT5C"},"sequence":{"accession":"Q86Y97","fasta_url":"https://rest.uniprot.org/uniprotkb/Q86Y97.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q86Y97/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86Y97"}},"corpus_meta":[{"pmid":"16322686","id":"PMC_16322686","title":"Loss of DNA methylation and histone H4 lysine 20 trimethylation in human breast cancer cells is associated with aberrant expression of DNA methyltransferase 1, Suv4-20h2 histone methyltransferase and methyl-binding proteins.","date":"2006","source":"Cancer biology & therapy","url":"https://pubmed.ncbi.nlm.nih.gov/16322686","citation_count":107,"is_preprint":false},{"pmid":"16497704","id":"PMC_16497704","title":"Histone H3 lysine 9 and H4 lysine 20 trimethylation and the expression of Suv4-20h2 and Suv-39h1 histone methyltransferases in hepatocarcinogenesis induced by methyl deficiency in rats.","date":"2006","source":"Carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/16497704","citation_count":101,"is_preprint":false},{"pmid":"23599346","id":"PMC_23599346","title":"Suv4-20h2 mediates chromatin compaction and is important for cohesin recruitment to heterochromatin.","date":"2013","source":"Genes & 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Progression","date":"2024-09-25","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.24.24314303","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":19960,"output_tokens":6532,"usd":0.07893,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":15412,"output_tokens":6337,"usd":0.117742,"stage2_stop_reason":"end_turn"},"total_usd":0.196672,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2013,\n      \"finding\": \"SUV420H2 (KMT5C) stably associates with pericentric heterochromatin through synergistic interactions with multiple HP1 molecules, mediating chromatin compaction. Cohesin subunits interact with SUV420H2 both in vitro and in vivo, and this interaction is necessary for cohesin binding to heterochromatin. SUV420H2-deficient cells display reduced sister chromatid cohesion and chromosome segregation defects during mitosis.\",\n      \"method\": \"Tandem affinity purification, Co-IP (in vivo and in vitro), FRAP, immunofluorescence, Suv4-20h mutant cell analysis\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP in vitro and in vivo, functional KO phenotype with multiple orthogonal readouts (cohesion, segregation, chromatin compaction), replicated across conditions\",\n      \"pmids\": [\"23599346\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"SUV420H2 interacts with HP1 proteins (identified as main partners by TAP-MS), with the interaction mapped to the heterochromatic targeting module (HTM) of SUV420H2 and the HP1 chromoshadow domain. FRAP reveals that SUV420H2 is strongly and stably bound to pericentric heterochromatin (in contrast to highly mobile HP1), and an 88 amino-acid HTM region recapitulates both HP1 binding and stable heterochromatin association.\",\n      \"method\": \"Tandem affinity purification/mass spectrometry (TAP-MS), FRAP, immunofluorescence, domain mapping\",\n      \"journal\": \"BMC cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — TAP-MS plus FRAP plus domain mapping in single study with multiple orthogonal methods\",\n      \"pmids\": [\"19486527\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Crystal structures of human SUV420H2 (and SUV420H1) in complex with SAM were solved at high resolution. Both enzymes have a unique N-terminal domain and Zn-binding post-SET domain, and prefer monomethylated H4K20 as substrate in vitro. No H4K20 trimethylation activity was detected for either enzyme in a radioactivity-based assay, consistent with a conserved serine residue that forms a hydrogen bond with the target lysine side-chain and limits methylation level.\",\n      \"method\": \"X-ray crystallography, in vitro radioactivity-based methyltransferase assay, substrate specificity analysis\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus in vitro enzymatic assay with substrate specificity, rigorous controls, single study\",\n      \"pmids\": [\"24396869\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"SUV420H2-mediated H4K20me3 antagonizes hMOF-mediated H4K16 acetylation at gene promoters, blocking RNA Polymerase II escape from promoter-proximal pausing. Combined inhibition of H4K20me3 and DNA methylation allowed hMOF re-recruitment, H4K16Ac restoration, Pol II release into elongation, and reactivation of TMS1/ASC expression.\",\n      \"method\": \"ChIP, siRNA knockdown, pharmacological inhibition of DNA methylation, Pol II pausing assays, gene expression analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP with multiple histone marks, epistatic rescue experiment, and functional Pol II elongation assay in single study\",\n      \"pmids\": [\"21321083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"By in vitro methylation studies and SPOT peptide arrays, SUV420H2 strongly favors monomethylated H4K20 as substrate and generates only dimethylated H4K20 product. SUV420H2 recognition motif is X-Kme1-(IVLMK)-(LVFI)-X-(DEV), with relaxed specificity compared to SUV420H1. Novel non-histone substrates were identified: K1423 of Zinc finger protein castor homolog 1, K215 of Protein Mis18-beta, and K308 of Centromere protein U.\",\n      \"method\": \"In vitro methylation assay, SPOT peptide array substrate specificity mapping\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic reconstitution with systematic substrate specificity arrays, single rigorous study\",\n      \"pmids\": [\"27105552\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"QM/MM simulations demonstrated that Suv4-20h2 (KMT5C) generates dimethylated H4K20 from monomethylated substrate due to effective transition state stabilization via CH···O interactions and a cation-π interaction. The enzyme fails to catalyze monomethylation (less effective TS stabilization) and trimethylation (H4K20me2-containing reactant complex cannot adopt a reactive near-attack configuration for methyl transfer).\",\n      \"method\": \"QM/MM molecular dynamics and free energy (potential of mean force) simulations\",\n      \"journal\": \"Journal of chemical theory and computation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — rigorous computational mechanistic analysis but no experimental mutagenesis validation; single study\",\n      \"pmids\": [\"28489369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Exogenous delivery of SUV420H2 into MDA-MB-231 breast cancer cells induced selective downregulation of tensin-3 (a focal adhesion protein promoting cancer cell migration), associated with enrichment of H4K20me3 immediately upstream of the tensin-3 transcription start site. Depletion of tensin-3 suppressed breast cancer cell invasiveness, connecting SUV420H2/H4K20me3 loss to upregulation of cancer-promoting genes and invasion.\",\n      \"method\": \"Exogenous gene delivery, RNA-seq, ChIP (H4K20me3), siRNA knockdown, invasion assay\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP linking H4K20me3 to tensin-3 promoter and functional invasion rescue, single lab with two orthogonal approaches\",\n      \"pmids\": [\"25814362\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"SUV420H2 (KMT5C) represses epithelial gene expression through H4K20me3, thereby favoring the mesenchymal identity in pancreatic cancer. SUV420H2 knockdown elicited mesenchymal-to-epithelial transition, decreased stemness, and increased drug sensitivity in pancreatic cancer cell lines.\",\n      \"method\": \"siRNA knockdown, gene expression profiling, functional assays (EMT markers, stemness, drug sensitivity)\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KD with defined molecular and functional EMT phenotype, multiple readouts, single lab\",\n      \"pmids\": [\"29229751\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SUV420H2 localizes preferentially to constitutive (pericentric) heterochromatin, and co-expression with HP1α increased its targeting to pericentromeric regions. SUV420H2 facilitated an increase in pericentric H4K20me3 and maintained a Myogenin-enriched population during myogenic differentiation in C2C12 cells, acting as an epigenetic switch for myogenesis.\",\n      \"method\": \"Immunofluorescence, gain-of-function expression, C2C12 myogenic differentiation assay, HP1α co-expression\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — immunofluorescence localization plus functional differentiation assay, multiple conditions tested, single lab\",\n      \"pmids\": [\"21206904\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SUV420H2 depletion in embryonic stem (ES) cells leads to near-complete loss of H4K20me3 genome-wide, dysregulated gene expression, and delayed ES cell differentiation. SUV420H2-bound regions are enriched at repetitive DNA elements which become de-repressed upon knockout. Loss of SUV420H2 results in A/B compartment switching, perturbed chromatin insulation, and altered chromatin interactions of pericentric heterochromatin, indicating a role in 3D chromatin architecture.\",\n      \"method\": \"SUV420H2 knockout, ChIP-seq, RNA-seq, Hi-C, ChIP for H4K20me3\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with multiple genome-wide orthogonal methods (ChIP-seq, RNA-seq, Hi-C) in single rigorous study\",\n      \"pmids\": [\"33144397\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"KMT5C expression is induced by β3-adrenergic signaling in brown and beige fat. Adipocyte-specific KMT5C knockout leads to decreased thermogenic gene expression, susceptibility to diet-induced obesity, and glucose intolerance. Mechanistically, increased Trp53 (p53) expression due to decreased H4K20me3 on its proximal promoter is responsible for the metabolic phenotypes in KMT5C KO mice.\",\n      \"method\": \"Adipocyte-specific KO mice, ChIP (H4K20me3 at Trp53 promoter), gene expression analysis, metabolic phenotyping\",\n      \"journal\": \"PNAS\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO with ChIP linking H4K20me3 to Trp53 promoter repression, rescue experiments, multiple metabolic readouts\",\n      \"pmids\": [\"32839323\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Loss of KMT5C in NSCLC cells drives resistance to multiple EGFR inhibitors by upregulating the long noncoding RNA LINC01510, which promotes transcription of the oncogene MET, activating a bypass signaling mechanism. KMT5C catalyzes H4K20me3 required for repression of LINC01510.\",\n      \"method\": \"KMT5C knockdown/knockout, gene expression analysis, ChIP (H4K20me3), LINC01510 overexpression rescue, in vitro and in vivo drug resistance assays\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP linking H4K20me3 to LINC01510 locus, functional rescue, mechanistic pathway placement, single lab\",\n      \"pmids\": [\"35404406\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Upon influenza virus infection, the viral nucleoprotein (NP) binds Suv4-20h2, inactivating it and causing dissociation of cohesin from Suv4-20h2. This inactivation allows cohesin-mediated chromatin loop formation at HoxC8-HoxC6 loci, upregulating HoxC8 and HoxC6, which enhance viral replication by inhibiting Wnt-β-catenin-mediated interferon response.\",\n      \"method\": \"Co-IP (NP-Suv4-20h2 interaction), genetic deletion of Suv4-20h2, chromatin conformation analysis, in vivo influenza infection model\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifying viral NP as binding partner, genetic KO with functional chromatin loop and antiviral pathway readouts, single lab\",\n      \"pmids\": [\"34169237\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Suv4-20h2-mediated H4K20me3 is required for maintaining heterochromatin compaction in intestinal organoids and to prevent R-loop formation. Loss of Suv4-20h2 in right-sided colorectal cancer is associated with increased chromatin accessibility, stemness/Wnt signaling, and drives tumor progression; re-compaction with a histone demethylase inhibitor selectively reduced growth of right-sided cancer-derived tumors.\",\n      \"method\": \"Patient-derived organoids, mouse intestinal organoids, genetic manipulation, MNase assay, ChIP, gene expression profiling, xenograft transplantation\",\n      \"journal\": \"Gastroenterology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — MNase assay for chromatin compaction, ChIP, R-loop detection, and in vivo xenograft in single rigorous study with multiple orthogonal methods\",\n      \"pmids\": [\"36402192\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"KMT5C (SUV420H2) interacts with RAD51 and promotes RAD51/RAD54 complex formation, activating double-strand break repair by homologous recombination. This function depends on KMT5C methyltransferase activity. KMT5C knockdown or pharmacological inhibition with A196 sensitizes liver cancer cells to PARP inhibitors.\",\n      \"method\": \"Co-IP (KMT5C-RAD51), RAD51/RAD54 complex analysis, methyltransferase inhibitor (A196) treatment, KMT5C knockdown, DNA repair assays, xenograft models\",\n      \"journal\": \"Hepatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifying RAD51 as interacting partner, methyltransferase-activity-dependent functional requirement, functional drug synergy, single lab\",\n      \"pmids\": [\"37556368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"KMT5C heterochromatin retention is conferred by two HP1-interaction modules in the HTM, tethered by an intrinsically disordered linker. The first module uses adjacent sequences for avidity-based HP1 binding; the second increases HP1 effective concentration. FRAP reveals KMT5C undergoes rapid internal diffusion but minimal nucleoplasmic exchange. The linker is under evolutionary constraint for functional length, enabling cooperativity between modules across orthologs.\",\n      \"method\": \"FRAP, domain mutagenesis, heterologous linker experiments, heterochromatin recruitment assays\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — FRAP plus systematic domain mutagenesis plus heterologous linker experiments, multiple orthogonal approaches in single rigorous study\",\n      \"pmids\": [\"39562713\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Three HP1-binding motifs were identified within the SUV420H2 HTM. The HTM N-terminal region (containing first and second motifs) stabilizes HP1 on heterochromatin. The HTM C-terminal region (third motif) destabilizes HP1 on chromatin. An HTM V374D mutant (Val374→Asp in the second HP1 binding motif) localizes to heterochromatin without affecting HP1 stability, demonstrating the second motif is critical for locking HP1 on H3K9me3-enriched heterochromatin.\",\n      \"method\": \"Domain mapping, point mutagenesis (V374D), live-cell fluorescence imaging, HP1 stability assays\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mutagenesis plus live-cell imaging, mechanistic dissection of HP1 binding motifs, single lab\",\n      \"pmids\": [\"38403935\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KMT5C regulates hepatic gluconeogenesis through a non-catalytic mechanism: it impedes the E3 ligase RNF34 from binding the C-terminal of PGC-1α, thereby blocking ubiquitination-mediated PGC-1α degradation and maintaining gluconeogenic gene expression. This function is independent of KMT5C methyltransferase activity.\",\n      \"method\": \"Hepatocyte-specific KO mice, Co-IP (KMT5C-RNF34-PGC-1α), ubiquitination assay, methyltransferase-inactive mutant, gluconeogenesis and glucose output assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP identifying RNF34 and PGC-1α as partners, catalytic mutant establishing non-enzymatic mechanism, in vivo KO with metabolic phenotype, multiple orthogonal methods\",\n      \"pmids\": [\"39929827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"SUV420H2 (Suv420h2) catalyzes H4K20 trimethylation at the 4e-bp1 promoter, leading to downregulated expression of 4E-BP1 (a negative regulator of translation initiation), which in turn increases PGC1α protein levels and thermogenic gene expression in brown/beige adipocytes.\",\n      \"method\": \"Suv420h2 KO and adipocyte-specific overexpression mice, ChIP (H4K20me3 at 4e-bp1 promoter), gene and protein expression analysis, cold tolerance and obesity phenotyping\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP linking H4K20me3 to 4e-bp1 promoter, in vivo KO and OE with functional thermogenic phenotype, single lab\",\n      \"pmids\": [\"38713533\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KMT5C activates the DNA repair response and inhibits the STING-IRF3 pathway and downstream type I IFN signaling in NSCLC, reducing CCL5 secretion and CD8+ T cell infiltration, thereby facilitating tumor immune evasion. Pharmacological inhibition (A196) or genetic inhibition of KMT5C synergizes with anti-PD-1 therapy.\",\n      \"method\": \"KMT5C knockdown/inhibition, STING-IRF3 pathway assays, cytokine measurement, immune cell profiling, in vivo mouse lung cancer models with anti-PD-1 combination\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic and pharmacological KD with defined immunological pathway readouts, in vivo combination therapy, single lab\",\n      \"pmids\": [\"40126333\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SUV420H2 (KMT5C) epigenetically silences DHRS2 through H4K20me3 deposition at its promoter in renal cell carcinoma. SUV420H2 knockdown leads to DHRS2 upregulation and cell apoptosis; co-knockdown of DHRS2 attenuates this effect, placing SUV420H2-mediated H4K20me3 upstream of DHRS2-dependent cell survival.\",\n      \"method\": \"siRNA knockdown, ChIP (H4K20me3 at DHRS2 promoter), rescue co-knockdown, A-196 inhibitor treatment, cell viability/apoptosis assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP linking H4K20me3 to DHRS2 promoter, epistatic rescue experiment, single lab\",\n      \"pmids\": [\"37119764\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KMT5C suppresses OSCC progression by epigenetically silencing UPP1 via H4K20me3 deposition at the UPP1 promoter. Transcription factor NR2C2 is responsible for recruiting KMT5C to the UPP1 promoter to achieve this H4K20me3 modification and transcriptional inhibition.\",\n      \"method\": \"KMT5C overexpression and knockdown, ChIP (H4K20me3 at UPP1 promoter), NR2C2 interaction/recruitment assay, in vitro and in vivo functional assays\",\n      \"journal\": \"Laboratory investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP linking H4K20me3 to UPP1 promoter, NR2C2 recruitment mechanism, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"39954852\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Suv420h2 loss-of-function (siRNA depletion) in osteoblast precursors results in loss of H4K20 methylation and decreased expression of osteogenic biomarkers (alkaline phosphatase/Alpl) and transcription factors (Sp7/Osterix), and impairs matrix mineralization, establishing Suv420h2 as required for normal osteoblast differentiation progression.\",\n      \"method\": \"siRNA knockdown, H4K20 methylation assay, gene expression analysis, alkaline phosphatase/mineralization assays\",\n      \"journal\": \"Journal of cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — KD with defined molecular and functional osteoblast differentiation phenotype, multiple markers, single lab\",\n      \"pmids\": [\"27862226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"KMT5C deposits H4K20me3 in a non-canonical manner, independent of H3K9me3 (previously considered a prerequisite). This non-canonical H4K20me3 lacks canonical repressive epigenetic signatures and instead overlaps with activating marks. ZNF280C was identified as a novel KMT5C-interacting partner localizing specifically at H3K9me3-/H4K20me3+ sites, mediating HP1-independent recruitment of KMT5C to these loci.\",\n      \"method\": \"ChIP-seq (H4K20me3, H3K9me3, activating marks), biochemical pulldown/Co-IP (KMT5C-ZNF280C), RNA-seq upon KMT5C loss\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — ChIP-seq and biochemical Co-IP identifying ZNF280C, preprint not yet peer-reviewed, single lab\",\n      \"pmids\": [\"42182233\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"KMT5C (SUV420H2) is a lysine methyltransferase that preferentially converts monomethylated H4K20 to the di- and trimethylated states (H4K20me2/3), targeting pericentric heterochromatin through cooperative binding to HP1 proteins via multiple interaction motifs in its heterochromatic targeting module; H4K20me3 deposited by KMT5C maintains chromatin compaction, recruits cohesin to heterochromatin (required for sister chromatid cohesion and chromosome segregation), represses repetitive elements and gene transcription by antagonizing H4K16 acetylation and blocking RNA Pol II elongation, and regulates 3D chromatin architecture; beyond canonical heterochromatin, KMT5C also deposits H4K20me3 at non-canonical loci via ZNF280C and exerts non-catalytic functions (e.g., stabilizing PGC-1α by blocking RNF34-mediated ubiquitination) and interacts with RAD51 to promote homologous recombination repair, collectively making KMT5C a multifunctional epigenetic regulator of genome integrity, gene expression, differentiation, metabolism, and immune signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KMT5C (SUV420H2) is a SAM-dependent lysine methyltransferase that deposits di- and trimethylated H4K20 (H4K20me2/3) to establish and maintain repressive heterochromatin, thereby controlling genome integrity, gene expression, differentiation, and metabolism [#0, #2]. Structurally it carries a unique N-terminal domain and a Zn-binding post-SET domain, prefers monomethylated H4K20 as substrate, and is intrinsically limited to producing dimethyl product by a conserved serine that hydrogen-bonds the target lysine, with transition-state geometry favoring H4K20me2 over me1 or me3 [#2, #4, #5]. The enzyme is stably retained at pericentric heterochromatin through a heterochromatic targeting module that engages the HP1 chromoshadow domain; this module contains multiple HP1-binding motifs tethered by a length-constrained intrinsically disordered linker that confers avidity-based, cooperative HP1 locking on H3K9me3 chromatin [#1, #15, #16]. At heterochromatin, KMT5C-generated H4K20me3 maintains chromatin compaction, recruits cohesin to enable sister chromatid cohesion and accurate chromosome segregation, organizes 3D chromatin architecture, and represses repetitive elements [#0, #9]. It silences specific gene promoters by antagonizing hMOF-mediated H4K16 acetylation and blocking RNA Pol II escape from promoter-proximal pausing [#3]. KMT5C acts as an epigenetic switch in cell-fate programs including myogenic and osteoblast differentiation [#8, #22], and controls thermogenic and gluconeogenic metabolism both catalytically — repressing Trp53 and 4e-bp1 promoters in adipocytes [#10, #18] — and non-catalytically, by shielding PGC-1\\u03b1 from RNF34-mediated ubiquitination [#17]. In cancer, loss of KMT5C-dependent H4K20me3 de-represses pro-tumorigenic loci and influences EMT, invasion, drug resistance, and immune evasion, while its methyltransferase activity additionally promotes RAD51/RAD54-mediated homologous recombination repair [#13, #14, #19]. Beyond canonical heterochromatin, KMT5C can deposit H4K20me3 at H3K9me3-negative loci via the partner ZNF280C, indicating an HP1-independent targeting route [#23].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"Established how KMT5C is anchored to heterochromatin, answering what tethers the enzyme stably to its site of action.\",\n      \"evidence\": \"TAP-MS, FRAP and domain mapping identifying HP1 binding via an 88-aa heterochromatic targeting module\",\n      \"pmids\": [\"19486527\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve the stoichiometry or cooperativity of HP1 engagement\", \"No structural model of the HTM-HP1 interface\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Connected KMT5C heterochromatin targeting to a cell-fate decision, showing it functions as an epigenetic switch in differentiation.\",\n      \"evidence\": \"Immunofluorescence, HP1\\u03b1 co-expression and C2C12 myogenic differentiation assays\",\n      \"pmids\": [\"21206904\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Gain-of-function only; loss-of-function not tested here\", \"Target genes driving the myogenic switch not defined\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Defined a mechanism of gene repression, showing H4K20me3 antagonizes H4K16 acetylation to control transcription elongation.\",\n      \"evidence\": \"ChIP for multiple histone marks, siRNA, DNA-methylation inhibition and Pol II pausing assays with epistatic rescue\",\n      \"pmids\": [\"21321083\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which H4K20me3 excludes hMOF not resolved\", \"Generality across loci untested in this study\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Revealed a structural role for KMT5C in mitotic chromosome biology by linking it physically and functionally to cohesin loading at heterochromatin.\",\n      \"evidence\": \"Tandem affinity purification, reciprocal Co-IP in vitro and in vivo, FRAP, and Suv4-20h KO phenotyping of cohesion and segregation\",\n      \"pmids\": [\"23599346\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether cohesin recruitment requires catalytic H4K20me3 or scaffolding alone not separated\", \"Direct cohesin-binding interface not mapped\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Provided the structural and biochemical basis for KMT5C's product specificity, explaining why it stops at H4K20me2 in vitro.\",\n      \"evidence\": \"X-ray crystallography of SUV420H2-SAM and in vitro radioactivity-based methyltransferase assays\",\n      \"pmids\": [\"24396869\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Apparent me2-only ceiling in vitro is hard to reconcile with H4K20me3 deposition in cells\", \"No structure of an enzyme-nucleosome complex\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Extended KMT5C activity beyond histones by defining its recognition motif and identifying non-histone substrates.\",\n      \"evidence\": \"In vitro methylation assays and SPOT peptide array substrate-specificity mapping\",\n      \"pmids\": [\"27105552\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Non-histone substrate methylation not validated in cells\", \"Functional consequence of CASZ1/MIS18B/CENPU methylation unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Established KMT5C as required for osteoblast differentiation, broadening its role across cell-lineage programs.\",\n      \"evidence\": \"siRNA knockdown with H4K20 methylation, osteogenic marker expression and mineralization assays\",\n      \"pmids\": [\"27862226\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct gene targets in osteoblasts not identified\", \"siRNA only; no genetic or in vivo confirmation\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Provided a computational mechanistic explanation for KMT5C's dimethyl product specificity at the transition-state level.\",\n      \"evidence\": \"QM/MM molecular dynamics and free-energy (potential of mean force) simulations\",\n      \"pmids\": [\"28489369\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No experimental mutagenesis validation of predicted catalytic determinants\", \"Does not address in vivo H4K20me3\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Linked KMT5C-mediated repression to cancer cell identity, showing it enforces mesenchymal state and stemness.\",\n      \"evidence\": \"siRNA knockdown with EMT-marker, stemness and drug-sensitivity profiling in pancreatic cancer lines\",\n      \"pmids\": [\"29229751\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific repressed epithelial gene targets not enumerated\", \"Knockdown only; no in vivo validation\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Demonstrated genome-wide that KMT5C is the principal H4K20me3 writer controlling repeat silencing and 3D chromatin architecture.\",\n      \"evidence\": \"ESC knockout with ChIP-seq, RNA-seq and Hi-C\",\n      \"pmids\": [\"33144397\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Causal link between compartment switching and transcriptional changes not dissected\", \"Mechanism of repeat de-repression beyond H4K20me3 loss unresolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Established a physiological metabolic role, showing KMT5C represses Trp53 to enable adipose thermogenesis.\",\n      \"evidence\": \"Adipocyte-specific KO mice with ChIP at the Trp53 promoter and metabolic phenotyping\",\n      \"pmids\": [\"32839323\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How \\u03b23-adrenergic signaling induces KMT5C transcription not defined\", \"Whether other adipose targets contribute not addressed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Revealed KMT5C as a target of viral subversion, where influenza NP inactivates it to release cohesin and reprogram chromatin loops.\",\n      \"evidence\": \"Co-IP of NP-Suv4-20h2, Suv4-20h2 deletion, chromatin conformation analysis and in vivo infection\",\n      \"pmids\": [\"34169237\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of NP-mediated inactivation not defined\", \"Single-lab finding without independent confirmation\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Connected loss of KMT5C-dependent repression to targeted-therapy resistance via lncRNA-driven bypass signaling.\",\n      \"evidence\": \"KMT5C knockdown/KO, ChIP at LINC01510, LINC01510 rescue, and drug-resistance assays in NSCLC\",\n      \"pmids\": [\"35404406\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking LINC01510 to MET transcription not fully resolved\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Tied KMT5C-maintained heterochromatin compaction to genome stability and tumor suppression in the intestine.\",\n      \"evidence\": \"Patient-derived and mouse organoids, MNase compaction assay, ChIP, R-loop detection and xenografts\",\n      \"pmids\": [\"36402192\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How H4K20me3 loss promotes R-loops mechanistically unclear\", \"Right-sided specificity determinants not defined\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identified a catalytic role for KMT5C in DNA repair by promoting RAD51/RAD54 complex formation during homologous recombination.\",\n      \"evidence\": \"Co-IP of KMT5C-RAD51, complex-formation analysis, methyltransferase inhibitor A196, knockdown and xenografts\",\n      \"pmids\": [\"37556368\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The relevant methylation substrate in HR not identified\", \"Single Co-IP-based interaction without reciprocal structural mapping\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Added a cancer-survival target gene, placing KMT5C-mediated H4K20me3 upstream of DHRS2-dependent apoptosis control.\",\n      \"evidence\": \"siRNA knockdown, ChIP at DHRS2 promoter, epistatic co-knockdown rescue and A-196 treatment in RCC\",\n      \"pmids\": [\"37119764\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Recruitment mechanism to the DHRS2 locus unknown\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Resolved the biophysical logic of heterochromatin retention, showing two HP1 modules joined by a length-constrained disordered linker confer cooperative binding.\",\n      \"evidence\": \"FRAP, domain mutagenesis and heterologous linker swaps in recruitment assays\",\n      \"pmids\": [\"39562713\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic structure of the two-module-HP1 assembly not determined\", \"How retention couples to catalytic turnover unaddressed\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Dissected the individual HP1-binding motifs, defining one motif as critical for locking HP1 onto H3K9me3 heterochromatin.\",\n      \"evidence\": \"Domain mapping, V374D point mutagenesis and live-cell imaging with HP1 stability assays\",\n      \"pmids\": [\"38403935\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of HP1 stabilization vs destabilization for catalysis not tested\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Extended adipose regulation, showing KMT5C-dependent repression of 4e-bp1 raises PGC1\\u03b1 protein and thermogenic output.\",\n      \"evidence\": \"Suv420h2 KO and adipocyte-specific overexpression mice, ChIP at the 4e-bp1 promoter and thermogenic phenotyping\",\n      \"pmids\": [\"38713533\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Reported H4K20me3 at 4e-bp1 vs in vitro me2-only ceiling not reconciled\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Established a methyltransferase-independent function, showing KMT5C scaffolds PGC-1\\u03b1 stability by blocking RNF34-mediated ubiquitination in liver.\",\n      \"evidence\": \"Hepatocyte-specific KO mice, Co-IP of KMT5C-RNF34-PGC-1\\u03b1, ubiquitination assays and a catalytically inactive mutant\",\n      \"pmids\": [\"39929827\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the KMT5C-RNF34 competition not resolved\", \"Generality of non-catalytic scaffolding to other tissues untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked KMT5C to tumor immune evasion via suppression of STING-IRF3/type I IFN signaling and reduced CD8+ T cell infiltration.\",\n      \"evidence\": \"KMT5C knockdown/inhibition, STING-IRF3 and cytokine assays, immune profiling and anti-PD-1 combination in vivo\",\n      \"pmids\": [\"40126333\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether immune suppression is catalytic or via DNA-repair-mediated cGAS-STING attenuation not separated\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Added a transcription-factor-directed recruitment route, with NR2C2 bringing KMT5C to the UPP1 promoter to suppress OSCC.\",\n      \"evidence\": \"KMT5C overexpression/knockdown, ChIP at UPP1, NR2C2 recruitment assays and in vitro/in vivo functional tests\",\n      \"pmids\": [\"39954852\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct KMT5C-NR2C2 interaction interface not mapped\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Challenged the H3K9me3-prerequisite model, showing KMT5C can deposit non-canonical H4K20me3 at activating-mark loci via ZNF280C, independent of HP1.\",\n      \"evidence\": \"ChIP-seq of H4K20me3/H3K9me3/activating marks, Co-IP of KMT5C-ZNF280C and RNA-seq (preprint)\",\n      \"pmids\": [\"42182233\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Functional role of non-canonical H4K20me3 at active loci undefined\", \"ZNF280C recruitment mechanism not resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how KMT5C achieves H4K20 trimethylation in cells given the in vitro and computational evidence that the isolated enzyme stops at the dimethyl product.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No cofactor, partner, or chromatin-context determinant identified that enables H4K20me3 deposition\", \"No structure of KMT5C on a nucleosome substrate\", \"Discrepancy between cellular H4K20me3 ChIP and in vitro me2-only activity unexplained\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [2, 4, 0]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [1, 16]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [3, 9, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 1, 8]},\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [0, 1, 8, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [0, 3, 9]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [3, 9, 10]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [14]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [8, 9, 22]},\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [10, 17, 18]}\n    ],\n    \"complexes\": [\"pericentric heterochromatin\"],\n    \"partners\": [\"CBX5\", \"RAD51\", \"RAD54\", \"RNF34\", \"PPARGC1A\", \"ZNF280C\", \"NR2C2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}