{"gene":"PROSER1","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2021,"finding":"PROSER1 physically interacts with TET2, OGT, and UTX (a component of the MLL3/4 enhancer-associated complexes), forming a multi-protein complex.","method":"Co-immunoprecipitation / protein interaction studies (interactors identified experimentally)","journal":"Life science alliance","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP identifying multiple binding partners, independently followed up in subsequent papers","pmids":["34667079"],"is_preprint":false},{"year":2021,"finding":"PROSER1 mediates the interaction between OGT and TET2, thereby promoting TET2 O-GlcNAcylation and stabilizing TET2 protein.","method":"Co-immunoprecipitation, loss-of-function (PROSER1 knockout) with western blot readout of TET2 O-GlcNAcylation and protein levels","journal":"Life science alliance","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO phenotype plus direct biochemical demonstration of O-GlcNAcylation change, replicated in follow-up studies","pmids":["34667079"],"is_preprint":false},{"year":2021,"finding":"Loss of PROSER1 reduces enrichment of UTX, TET1/2, and OGT at enhancers and CpG islands, leading to increased DNA methylation and transcriptional downregulation of associated target genes.","method":"ChIP-seq and genome-wide DNA methylation analysis in PROSER1 knockout cells","journal":"Life science alliance","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide ChIP-seq and methylation profiling in KO cells, multiple orthogonal methods","pmids":["34667079"],"is_preprint":false},{"year":2021,"finding":"PROSER1 acts as a broader regulator of OGT activity, controlling O-GlcNAcylation of multiple chromatin-associated proteins beyond TET2.","method":"Loss-of-function (PROSER1 KO) with O-GlcNAcylation profiling of chromatin proteins","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab, single method (O-GlcNAc profiling in KO), not independently replicated for the broader claim","pmids":["34667079"],"is_preprint":false},{"year":2024,"finding":"PROSER1 interacts with all three TET enzymes (TET1, TET2, TET3) and stabilizes chromatin-bound TET-OGT-PROSER1-DBHS (TOPD) complexes that regulate DNA demethylation.","method":"Co-immunoprecipitation, chromatin fractionation, complex characterization","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct interaction demonstrated with all TET family members, complex defined with multiple components, single lab","pmids":["39562138"],"is_preprint":false},{"year":2024,"finding":"Beyond promoting TET activity, PROSER1 also sequesters TET enzymes to prevent widespread DNA demethylation and transposable element derepression, acting as a dual positive and negative regulator of TET-mediated demethylation.","method":"Loss-of-function mouse models with genome-wide DNA methylation analysis and transposable element expression assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo KO with genome-wide methylation sequencing and TE derepression readout, multiple orthogonal methods in single rigorous study","pmids":["39562138"],"is_preprint":false},{"year":2025,"finding":"Loss of PROSER1 partially recapitulates the aberrant enhancer DNA hypermethylation phenotype of TET2 knockout in hematopoietic cells, indicating cooperative but also distinct roles for PROSER1 and TET2 in regulating DNA methylation during hematopoiesis.","method":"PROSER1 knockout mouse model with DNA methylation profiling at enhancers (compared to TET2 KO)","journal":"Blood advances","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab, KO with methylation profiling, epistasis-like comparison to TET2 KO, no independent replication yet","pmids":["40554416"],"is_preprint":false},{"year":2025,"finding":"Loss of PROSER1 leads to progressive exhaustion of hematopoietic stem cell (HSC) activity and reduced hematopoietic lineage output, as demonstrated by serial HSC transplantation assays.","method":"Serial hematopoietic stem cell transplantation assays in PROSER1 knockout mice","journal":"Blood advances","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — rigorous functional assay (serial transplantation) with defined cellular phenotype, single lab, no independent replication yet","pmids":["40554416"],"is_preprint":false},{"year":2025,"finding":"The leukemia-suppressive functions of TET2 are preserved in the absence of PROSER1, indicating PROSER1 is not required for TET2's tumor-suppressive role in hematopoiesis.","method":"PROSER1 knockout mouse model assessed for hematological malignancy phenotypes (negative result for leukemogenesis)","journal":"Blood advances","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab, in vivo KO with hematological phenotyping; negative result is mechanistically informative for pathway placement","pmids":["40554416"],"is_preprint":false}],"current_model":"PROSER1 is a proline/serine-rich protein that forms TET-OGT-PROSER1-DBHS (TOPD) complexes with all TET enzymes and OGT, bridging OGT to TET2 to promote TET2 O-GlcNAcylation and protein stability; it co-localizes with UTX (MLL3/4 complex) at enhancers and CpG islands to support DNA demethylation and gene activation, while simultaneously sequestering TET enzymes to prevent uncontrolled demethylation and transposable element derepression, and its loss impairs hematopoietic stem cell self-renewal without abrogating TET2's leukemia-suppressive function."},"narrative":{"mechanistic_narrative":"PROSER1 is a chromatin-associated scaffolding protein that couples O-GlcNAc signaling to TET-mediated DNA demethylation at regulatory elements [PMID:34667079, PMID:39562138]. It physically bridges OGT to TET2, mediating TET2 O-GlcNAcylation and stabilizing TET2 protein, and more broadly regulates OGT-dependent O-GlcNAcylation of chromatin-associated proteins [PMID:34667079]. PROSER1 interacts with all three TET enzymes and with UTX (a component of the MLL3/4 enhancer-associated complexes), assembling chromatin-bound TET-OGT-PROSER1-DBHS (TOPD) complexes [PMID:34667079, PMID:39562138]; its loss reduces recruitment of UTX, TET1/2, and OGT to enhancers and CpG islands, causing DNA hypermethylation and transcriptional downregulation of target genes [PMID:34667079]. PROSER1 acts as a dual regulator of demethylation, both supporting TET activity and sequestering TET enzymes to restrain widespread demethylation and transposable element derepression [PMID:39562138]. In hematopoiesis, PROSER1 loss partially phenocopies the enhancer hypermethylation of TET2 knockout and drives progressive exhaustion of hematopoietic stem cell self-renewal, yet TET2's leukemia-suppressive function is preserved without PROSER1, marking cooperative but separable roles [PMID:40554416].","teleology":[{"year":2021,"claim":"Establishing that PROSER1 is a physical scaffold linking the O-GlcNAc machinery to TET and MLL3/4 demethylation/activation activities answered how these enzymes are co-recruited to chromatin.","evidence":"Reciprocal co-immunoprecipitation identifying TET2, OGT, and UTX as interactors","pmids":["34667079"],"confidence":"High","gaps":["Stoichiometry and architecture of the complex not resolved","Direct vs. indirect nature of each contact not fully dissected"]},{"year":2021,"claim":"Defining PROSER1 as the bridge that delivers OGT to TET2 explained how TET2 is O-GlcNAcylated and stabilized, linking PROSER1 to TET2 protein homeostasis.","evidence":"PROSER1 knockout with western-blot readout of TET2 O-GlcNAcylation and protein levels","pmids":["34667079"],"confidence":"High","gaps":["O-GlcNAc site(s) on TET2 not mapped","Whether stabilization is solely O-GlcNAc-dependent unclear"]},{"year":2021,"claim":"Genome-wide profiling showed PROSER1 is required for enhancer/CpG-island recruitment of the demethylation machinery, establishing its functional consequence for DNA methylation and gene expression.","evidence":"ChIP-seq and genome-wide DNA methylation analysis in knockout cells","pmids":["34667079"],"confidence":"High","gaps":["Direct vs. secondary effects on individual loci not separated"]},{"year":2021,"claim":"Profiling chromatin O-GlcNAcylation beyond TET2 positioned PROSER1 as a broader regulator of OGT activity on chromatin proteins.","evidence":"O-GlcNAcylation profiling of chromatin proteins in PROSER1 knockout","pmids":["34667079"],"confidence":"Medium","gaps":["Single lab, single method; broader claim not independently replicated","Specific additional substrates not enumerated"]},{"year":2024,"claim":"Demonstrating interaction with all three TET enzymes and defining the chromatin-bound TOPD complex generalized PROSER1's role across the TET family.","evidence":"Co-immunoprecipitation, chromatin fractionation, and complex characterization","pmids":["39562138"],"confidence":"High","gaps":["Whether TET1/TET3 are O-GlcNAcylated like TET2 not established","DBHS subunit contribution to complex function unclear"]},{"year":2024,"claim":"In vivo loss-of-function revealed PROSER1 is a dual regulator that both promotes and restrains demethylation, resolving how excess demethylation and transposable element derepression are prevented.","evidence":"Loss-of-function mouse models with genome-wide methylation sequencing and transposable element expression assays","pmids":["39562138"],"confidence":"High","gaps":["Molecular switch between positive and negative modes not defined","Locus determinants of sequestration vs. activation unknown"]},{"year":2025,"claim":"Comparing PROSER1 and TET2 knockouts in hematopoietic cells placed PROSER1 in the TET2 demethylation pathway while revealing non-overlapping functions.","evidence":"PROSER1 knockout mouse with enhancer DNA methylation profiling compared to TET2 knockout","pmids":["40554416"],"confidence":"Medium","gaps":["Single lab, not independently replicated","Basis of distinct (non-shared) methylation effects not defined"]},{"year":2025,"claim":"Serial transplantation defined a physiological requirement for PROSER1 in hematopoietic stem cell self-renewal.","evidence":"Serial HSC transplantation assays in PROSER1 knockout mice","pmids":["40554416"],"confidence":"Medium","gaps":["Molecular link between methylation changes and HSC exhaustion not established","Single lab, no independent replication"]},{"year":2025,"claim":"Showing TET2's tumor-suppressive role persists without PROSER1 separated PROSER1's self-renewal function from TET2-mediated leukemia suppression.","evidence":"PROSER1 knockout mouse assessed for hematological malignancy (negative result)","pmids":["40554416"],"confidence":"Medium","gaps":["Which TET2 functions are PROSER1-independent not mechanistically dissected","Negative result from single model"]},{"year":null,"claim":"The molecular determinants that toggle PROSER1 between promoting TET recruitment and sequestering TET to limit demethylation, and how this connects to HSC self-renewal, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the TOPD complex","Switch mechanism between activating and sequestering modes undefined","Causal chain from methylation defects to stem cell exhaustion not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,4]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,3,5]}],"localization":[{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[2,4]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[2]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[2,4,5]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[2]}],"complexes":["TET-OGT-PROSER1-DBHS (TOPD) complex","MLL3/4 (UTX) enhancer-associated complex"],"partners":["TET1","TET2","TET3","OGT","UTX"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q86XN7","full_name":"Proline and serine-rich protein 1","aliases":[],"length_aa":944,"mass_kda":95.7,"function":"Mediates OGT interaction with and O-GlcNAcylation of TET2 to control TET2 stabilization at enhancers and CpG islands (CGIs)","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/Q86XN7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PROSER1","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":"PSPC1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/PROSER1","total_profiled":1310},"omim":[{"mim_id":"620773","title":"PROLINE- AND SERINE-RICH PROTEIN 1; PROSER1","url":"https://www.omim.org/entry/620773"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/PROSER1"},"hgnc":{"alias_symbol":["bA50D16.2","FLJ12661"],"prev_symbol":["C13orf23"]},"alphafold":{"accession":"Q86XN7","domains":[{"cath_id":"1.25.40","chopping":"4-128","consensus_level":"medium","plddt":89.7748,"start":4,"end":128}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86XN7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q86XN7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q86XN7-F1-predicted_aligned_error_v6.png","plddt_mean":44.47},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PROSER1","jax_strain_url":"https://www.jax.org/strain/search?query=PROSER1"},"sequence":{"accession":"Q86XN7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q86XN7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q86XN7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86XN7"}},"corpus_meta":[{"pmid":"34667079","id":"PMC_34667079","title":"PROSER1 mediates TET2 O-GlcNAcylation to regulate DNA demethylation on UTX-dependent enhancers and CpG islands.","date":"2021","source":"Life science alliance","url":"https://pubmed.ncbi.nlm.nih.gov/34667079","citation_count":30,"is_preprint":false},{"pmid":"35229282","id":"PMC_35229282","title":"A homozygous frame-shift variant in PROSER1 is associated with developmental delay, hypotonia, genitourinary malformations, and distinctive facial features.","date":"2022","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35229282","citation_count":6,"is_preprint":false},{"pmid":"39562138","id":"PMC_39562138","title":"PROSER1 modulates DNA demethylation through dual mechanisms to prevent syndromic developmental malformations.","date":"2024","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/39562138","citation_count":4,"is_preprint":false},{"pmid":"40554416","id":"PMC_40554416","title":"The TET protein family interactor PROSER1 sustains hematopoietic stem cell function.","date":"2025","source":"Blood advances","url":"https://pubmed.ncbi.nlm.nih.gov/40554416","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4089,"output_tokens":1893,"usd":0.020331,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8730,"output_tokens":2860,"usd":0.057575,"stage2_stop_reason":"end_turn"},"total_usd":0.077906,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"PROSER1 physically interacts with TET2, OGT, and UTX (a component of the MLL3/4 enhancer-associated complexes), forming a multi-protein complex.\",\n      \"method\": \"Co-immunoprecipitation / protein interaction studies (interactors identified experimentally)\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP identifying multiple binding partners, independently followed up in subsequent papers\",\n      \"pmids\": [\"34667079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PROSER1 mediates the interaction between OGT and TET2, thereby promoting TET2 O-GlcNAcylation and stabilizing TET2 protein.\",\n      \"method\": \"Co-immunoprecipitation, loss-of-function (PROSER1 knockout) with western blot readout of TET2 O-GlcNAcylation and protein levels\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO phenotype plus direct biochemical demonstration of O-GlcNAcylation change, replicated in follow-up studies\",\n      \"pmids\": [\"34667079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Loss of PROSER1 reduces enrichment of UTX, TET1/2, and OGT at enhancers and CpG islands, leading to increased DNA methylation and transcriptional downregulation of associated target genes.\",\n      \"method\": \"ChIP-seq and genome-wide DNA methylation analysis in PROSER1 knockout cells\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide ChIP-seq and methylation profiling in KO cells, multiple orthogonal methods\",\n      \"pmids\": [\"34667079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PROSER1 acts as a broader regulator of OGT activity, controlling O-GlcNAcylation of multiple chromatin-associated proteins beyond TET2.\",\n      \"method\": \"Loss-of-function (PROSER1 KO) with O-GlcNAcylation profiling of chromatin proteins\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab, single method (O-GlcNAc profiling in KO), not independently replicated for the broader claim\",\n      \"pmids\": [\"34667079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PROSER1 interacts with all three TET enzymes (TET1, TET2, TET3) and stabilizes chromatin-bound TET-OGT-PROSER1-DBHS (TOPD) complexes that regulate DNA demethylation.\",\n      \"method\": \"Co-immunoprecipitation, chromatin fractionation, complex characterization\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct interaction demonstrated with all TET family members, complex defined with multiple components, single lab\",\n      \"pmids\": [\"39562138\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Beyond promoting TET activity, PROSER1 also sequesters TET enzymes to prevent widespread DNA demethylation and transposable element derepression, acting as a dual positive and negative regulator of TET-mediated demethylation.\",\n      \"method\": \"Loss-of-function mouse models with genome-wide DNA methylation analysis and transposable element expression assays\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo KO with genome-wide methylation sequencing and TE derepression readout, multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"39562138\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Loss of PROSER1 partially recapitulates the aberrant enhancer DNA hypermethylation phenotype of TET2 knockout in hematopoietic cells, indicating cooperative but also distinct roles for PROSER1 and TET2 in regulating DNA methylation during hematopoiesis.\",\n      \"method\": \"PROSER1 knockout mouse model with DNA methylation profiling at enhancers (compared to TET2 KO)\",\n      \"journal\": \"Blood advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab, KO with methylation profiling, epistasis-like comparison to TET2 KO, no independent replication yet\",\n      \"pmids\": [\"40554416\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Loss of PROSER1 leads to progressive exhaustion of hematopoietic stem cell (HSC) activity and reduced hematopoietic lineage output, as demonstrated by serial HSC transplantation assays.\",\n      \"method\": \"Serial hematopoietic stem cell transplantation assays in PROSER1 knockout mice\",\n      \"journal\": \"Blood advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — rigorous functional assay (serial transplantation) with defined cellular phenotype, single lab, no independent replication yet\",\n      \"pmids\": [\"40554416\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"The leukemia-suppressive functions of TET2 are preserved in the absence of PROSER1, indicating PROSER1 is not required for TET2's tumor-suppressive role in hematopoiesis.\",\n      \"method\": \"PROSER1 knockout mouse model assessed for hematological malignancy phenotypes (negative result for leukemogenesis)\",\n      \"journal\": \"Blood advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab, in vivo KO with hematological phenotyping; negative result is mechanistically informative for pathway placement\",\n      \"pmids\": [\"40554416\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PROSER1 is a proline/serine-rich protein that forms TET-OGT-PROSER1-DBHS (TOPD) complexes with all TET enzymes and OGT, bridging OGT to TET2 to promote TET2 O-GlcNAcylation and protein stability; it co-localizes with UTX (MLL3/4 complex) at enhancers and CpG islands to support DNA demethylation and gene activation, while simultaneously sequestering TET enzymes to prevent uncontrolled demethylation and transposable element derepression, and its loss impairs hematopoietic stem cell self-renewal without abrogating TET2's leukemia-suppressive function.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PROSER1 is a chromatin-associated scaffolding protein that couples O-GlcNAc signaling to TET-mediated DNA demethylation at regulatory elements [#0, #4]. It physically bridges OGT to TET2, mediating TET2 O-GlcNAcylation and stabilizing TET2 protein, and more broadly regulates OGT-dependent O-GlcNAcylation of chromatin-associated proteins [#1, #3]. PROSER1 interacts with all three TET enzymes and with UTX (a component of the MLL3/4 enhancer-associated complexes), assembling chromatin-bound TET-OGT-PROSER1-DBHS (TOPD) complexes [#0, #4]; its loss reduces recruitment of UTX, TET1/2, and OGT to enhancers and CpG islands, causing DNA hypermethylation and transcriptional downregulation of target genes [#2]. PROSER1 acts as a dual regulator of demethylation, both supporting TET activity and sequestering TET enzymes to restrain widespread demethylation and transposable element derepression [#5]. In hematopoiesis, PROSER1 loss partially phenocopies the enhancer hypermethylation of TET2 knockout and drives progressive exhaustion of hematopoietic stem cell self-renewal, yet TET2's leukemia-suppressive function is preserved without PROSER1, marking cooperative but separable roles [#6, #7, #8].\",\n  \"teleology\": [\n    {\n      \"year\": 2021,\n      \"claim\": \"Establishing that PROSER1 is a physical scaffold linking the O-GlcNAc machinery to TET and MLL3/4 demethylation/activation activities answered how these enzymes are co-recruited to chromatin.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation identifying TET2, OGT, and UTX as interactors\",\n      \"pmids\": [\"34667079\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and architecture of the complex not resolved\", \"Direct vs. indirect nature of each contact not fully dissected\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Defining PROSER1 as the bridge that delivers OGT to TET2 explained how TET2 is O-GlcNAcylated and stabilized, linking PROSER1 to TET2 protein homeostasis.\",\n      \"evidence\": \"PROSER1 knockout with western-blot readout of TET2 O-GlcNAcylation and protein levels\",\n      \"pmids\": [\"34667079\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"O-GlcNAc site(s) on TET2 not mapped\", \"Whether stabilization is solely O-GlcNAc-dependent unclear\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Genome-wide profiling showed PROSER1 is required for enhancer/CpG-island recruitment of the demethylation machinery, establishing its functional consequence for DNA methylation and gene expression.\",\n      \"evidence\": \"ChIP-seq and genome-wide DNA methylation analysis in knockout cells\",\n      \"pmids\": [\"34667079\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs. secondary effects on individual loci not separated\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Profiling chromatin O-GlcNAcylation beyond TET2 positioned PROSER1 as a broader regulator of OGT activity on chromatin proteins.\",\n      \"evidence\": \"O-GlcNAcylation profiling of chromatin proteins in PROSER1 knockout\",\n      \"pmids\": [\"34667079\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, single method; broader claim not independently replicated\", \"Specific additional substrates not enumerated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrating interaction with all three TET enzymes and defining the chromatin-bound TOPD complex generalized PROSER1's role across the TET family.\",\n      \"evidence\": \"Co-immunoprecipitation, chromatin fractionation, and complex characterization\",\n      \"pmids\": [\"39562138\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether TET1/TET3 are O-GlcNAcylated like TET2 not established\", \"DBHS subunit contribution to complex function unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"In vivo loss-of-function revealed PROSER1 is a dual regulator that both promotes and restrains demethylation, resolving how excess demethylation and transposable element derepression are prevented.\",\n      \"evidence\": \"Loss-of-function mouse models with genome-wide methylation sequencing and transposable element expression assays\",\n      \"pmids\": [\"39562138\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular switch between positive and negative modes not defined\", \"Locus determinants of sequestration vs. activation unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Comparing PROSER1 and TET2 knockouts in hematopoietic cells placed PROSER1 in the TET2 demethylation pathway while revealing non-overlapping functions.\",\n      \"evidence\": \"PROSER1 knockout mouse with enhancer DNA methylation profiling compared to TET2 knockout\",\n      \"pmids\": [\"40554416\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, not independently replicated\", \"Basis of distinct (non-shared) methylation effects not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Serial transplantation defined a physiological requirement for PROSER1 in hematopoietic stem cell self-renewal.\",\n      \"evidence\": \"Serial HSC transplantation assays in PROSER1 knockout mice\",\n      \"pmids\": [\"40554416\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular link between methylation changes and HSC exhaustion not established\", \"Single lab, no independent replication\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showing TET2's tumor-suppressive role persists without PROSER1 separated PROSER1's self-renewal function from TET2-mediated leukemia suppression.\",\n      \"evidence\": \"PROSER1 knockout mouse assessed for hematological malignancy (negative result)\",\n      \"pmids\": [\"40554416\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Which TET2 functions are PROSER1-independent not mechanistically dissected\", \"Negative result from single model\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular determinants that toggle PROSER1 between promoting TET recruitment and sequestering TET to limit demethylation, and how this connects to HSC self-renewal, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the TOPD complex\", \"Switch mechanism between activating and sequestering modes undefined\", \"Causal chain from methylation defects to stem cell exhaustion not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 3, 5]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [2, 4, 5]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [\n      \"TET-OGT-PROSER1-DBHS (TOPD) complex\",\n      \"MLL3/4 (UTX) enhancer-associated complex\"\n    ],\n    \"partners\": [\n      \"TET1\",\n      \"TET2\",\n      \"TET3\",\n      \"OGT\",\n      \"UTX\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":5,"faith_pct":80.0}}