{"gene":"ZMYND19","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":2002,"finding":"MIZIP (ZMYND19) was identified as a binding partner of the C-terminus of melanin-concentrating hormone receptor 1 (MCH-R1). The interaction was verified by overlay assay, pull-down assay, and co-transfection experiments in HEK-293 cells. MIZIP is cytoplasmically localized but is recruited to the plasma membrane upon co-expression with MCH-R1.","method":"Yeast two-hybrid, overlay assay, GST pull-down, co-transfection/co-immunoprecipitation in HEK-293 cells, subcellular localization imaging","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — multiple orthogonal methods (Y2H, pull-down, co-IP, localization) in single lab","pmids":["12208518"],"is_preprint":false},{"year":2005,"finding":"MIZIP (ZMYND19) interacts with alpha- and beta-tubulin via its MYND zinc-finger domain; the interaction maps to the N-terminus of tubulin. MIZIP binds to free tubulin but not to assembled microtubules in vivo, and ectopic MIZIP expression does not disrupt the overall microtubular cytoskeleton.","method":"Affinity purification from human cells, GST pull-down (in vitro), co-immunoprecipitation (in vivo), immunocytochemistry, domain-mapping experiments","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — reciprocal co-IP and pull-down with domain mapping, single lab, multiple orthogonal methods","pmids":["16039987"],"is_preprint":false},{"year":2005,"finding":"MIZIP (ZMYND19) is present in cytoplasmic, membrane, and synaptosomal fractions of adult mouse brain (but not postsynaptic density). In cultured rat embryonic hippocampal neurons, MIZIP is somatodendritically localized. Co-expression with MCH-R1 is observed in multiple brain regions, supporting cell-type-specific interaction in vivo.","method":"Subcellular fractionation of adult mouse brain, immunoblotting, immunohistochemistry, immunofluorescence in cultured neurons","journal":"Brain research. Molecular brain research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — localization data from a single lab without functional consequence directly demonstrated","pmids":["15950311"],"is_preprint":false},{"year":2021,"finding":"ZMYND19 is a substrate of the human GID (hGID/CTLH) E3 ubiquitin ligase complex, recruited via the adaptor subunit GID4. Notably, ZMYND19 lacks a canonical Pro/N-end degron, distinguishing it from other GID4-dependent substrates. ARMC8α regulates GID4 substrate binding and ligase activity, while ARMC8β assembles a stable complex unable to recruit GID4.","method":"Biochemical ubiquitination assays, cross-linking mass spectrometry, cryo-electron microscopy, reconstitution of hGID complex","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure, in vitro reconstitution, and biochemical assays in one rigorous study","pmids":["34647674"],"is_preprint":false},{"year":2024,"finding":"ZMYND19 (and MKLN1) are substrates of the CTLH/MAEA E3 ubiquitin ligase; upon MAEA knockout, ZMYND19 accumulates and associates with lysosomes to inhibit mTORC1. ZMYND19 and MKLN1 bind Raptor and RagA/C and block a late stage of mTORC1 activation (not its lysosomal recruitment), independently of the tuberous sclerosis complex.","method":"Genome-wide CRISPR/Cas9 screen, MAEA knockout, co-immunoprecipitation, lysosomal fractionation, mTORC1 activity assays","journal":"Research square (preprint)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR screen plus co-IP and functional assays, single lab, preprint (superseded by peer-reviewed version)","pmids":["38746323"],"is_preprint":true},{"year":2025,"finding":"ZMYND19, a CTLH E3 ligase substrate, accumulates at lysosome outer membranes upon MAEA knockout and, together with MKLN1, inhibits mTORC1 by blocking the interaction between mTORC1 and Rheb and between mTORC1 and its substrates S6K and 4E-BP1 — rather than preventing mTORC1 lysosomal recruitment. This defines a ubiquitin/proteasome-based mechanism for rapid tuning of mTORC1 activity.","method":"Genome-wide CRISPR/Cas9 screen, MAEA knockout, co-immunoprecipitation (Raptor, RagA/C, Rheb), lysosome fractionation, mTORC1 substrate phosphorylation assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — peer-reviewed, multiple orthogonal methods (CRISPR screen, co-IP, fractionation, kinase assays) establishing pathway position and molecular mechanism","pmids":["41315365"],"is_preprint":false},{"year":2026,"finding":"ZMYND19 harbors a C-terminal degron recognized by the Muskelin substrate adaptor of the CTLH E3 ligase complex. CTLH-Muskelin-mediated degradation of ZMYND19 is conditionally regulated: impaired by TNF-α stimulation and enhanced by mTOR inhibition. This C-degron pathway connects conditional CTLH regulation to control of cellular processes including ribosome biogenesis.","method":"C-terminal capping expression screen for stability, genetic and proteomic screens, CTLH/Muskelin knockout, proteasome inhibitor assays, quantitative proteomics","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic C-degron screen plus genetic/proteomic validation, single lab, preprint only","pmids":["41648430"],"is_preprint":true}],"current_model":"ZMYND19 (MIZIP) is a MYND zinc-finger protein that interacts with MCH-R1 and free tubulin via its MYND domain; it is a substrate of the CTLH/GID E3 ubiquitin ligase complex (recruited through the GID4 adaptor and degraded via a Muskelin-dependent C-degron pathway), and when it escapes degradation, ZMYND19 accumulates at lysosome outer membranes where it associates with MKLN1, Raptor, and RagA/C to block Rheb–mTORC1 interaction and mTORC1 substrate phosphorylation, thereby negatively regulating mTORC1 signaling."},"narrative":{"mechanistic_narrative":"ZMYND19 (MIZIP) is a MYND zinc-finger protein that functions as a conditionally degraded substrate of the CTLH/GID E3 ubiquitin ligase and, when stabilized, as a negative regulator of mTORC1 signaling at the lysosome [PMID:34647674, PMID:41315365]. It was first identified as a cytoplasmic interactor of the C-terminus of melanin-concentrating hormone receptor 1 (MCH-R1), to which it is recruited at the plasma membrane upon receptor co-expression [PMID:12208518], and it additionally binds free α- and β-tubulin through its MYND domain without associating with assembled microtubules [PMID:16039987]. Mechanistically, ZMYND19 is recognized by the human GID/CTLH complex: it is captured via the GID4 adaptor despite lacking a canonical Pro/N-end degron [PMID:34647674], and is also targeted through a C-terminal degron read by the Muskelin adaptor, a degradation route tuned by TNF-α and mTOR inhibition [PMID:41648430]. When CTLH activity is lost, ZMYND19 escapes degradation and accumulates at lysosome outer membranes, where together with MKLN1 it binds Raptor and RagA/C and blocks the interactions of mTORC1 with Rheb and with its substrates S6K and 4E-BP1, inhibiting mTORC1 at a late activation step independently of the tuberous sclerosis complex and downstream of its lysosomal recruitment [PMID:38746323, PMID:41315365]. This places ZMYND19 in a ubiquitin/proteasome-based circuit for rapid tuning of mTORC1 activity and associated processes such as ribosome biogenesis [PMID:41315365, PMID:41648430].","teleology":[{"year":2002,"claim":"Established ZMYND19's first physical partner, linking the orphan protein to G-protein-coupled receptor signaling by showing it binds the MCH-R1 C-terminus and is recruited to the membrane.","evidence":"Yeast two-hybrid, overlay/GST pull-down, and co-IP with localization imaging in HEK-293 cells","pmids":["12208518"],"confidence":"Medium","gaps":["Functional consequence of the MCH-R1 interaction on receptor signaling not determined","Binding shown only in heterologous overexpression"]},{"year":2005,"claim":"Defined the MYND domain as a protein-interaction module by mapping tubulin binding to it, revealing ZMYND19 binds free but not polymerized tubulin.","evidence":"Affinity purification, in vitro GST pull-down, in vivo co-IP, and domain-mapping in human cells","pmids":["16039987"],"confidence":"Medium","gaps":["Biological role of tubulin binding unresolved — no microtubule phenotype observed","Single lab, no orthogonal structural confirmation"]},{"year":2005,"claim":"Provided native-tissue context by documenting ZMYND19 distribution and MCH-R1 co-expression in brain, supporting physiological relevance of the interaction.","evidence":"Subcellular fractionation, immunoblotting, and immunofluorescence in mouse brain and rat hippocampal neurons","pmids":["15950311"],"confidence":"Low","gaps":["Localization data without demonstrated functional consequence","No direct in vivo interaction assay in neurons"]},{"year":2021,"claim":"Identified ZMYND19 as a bona fide CTLH/GID E3 ligase substrate and showed it is recruited atypically via GID4 without a canonical Pro/N-end degron, expanding the substrate logic of this ligase.","evidence":"In vitro ubiquitination, cross-linking mass spectrometry, cryo-EM, and reconstitution of the hGID complex","pmids":["34647674"],"confidence":"High","gaps":["The actual degron motif on ZMYND19 recognized in this pathway not defined","Cellular consequence of ZMYND19 turnover not addressed"]},{"year":2024,"claim":"Connected ZMYND19 turnover to a function by showing that upon CTLH/MAEA loss it accumulates at lysosomes and, with MKLN1, binds Raptor and RagA/C to inhibit mTORC1 at a late, TSC-independent activation step.","evidence":"Genome-wide CRISPR screen, MAEA knockout, co-IP, lysosomal fractionation, and mTORC1 activity assays (preprint)","pmids":["38746323"],"confidence":"Medium","gaps":["Precise molecular block on mTORC1 not yet defined in this version","Preprint stage"]},{"year":2025,"claim":"Resolved the molecular mechanism of inhibition: stabilized ZMYND19/MKLN1 blocks mTORC1 binding to Rheb and to substrates S6K and 4E-BP1, defining a ubiquitin/proteasome circuit for rapid mTORC1 tuning.","evidence":"CRISPR screen, MAEA knockout, co-IP (Raptor, RagA/C, Rheb), lysosome fractionation, and substrate phosphorylation assays","pmids":["41315365"],"confidence":"High","gaps":["Physiological stimulus that normally stabilizes ZMYND19 to engage this brake not established","Structural basis of the Rheb/substrate block unknown"]},{"year":2026,"claim":"Identified a conditional C-degron pathway, showing ZMYND19 is degraded via the Muskelin adaptor of CTLH in a manner tuned by TNF-α and mTOR inhibition, linking ligase regulation to ribosome biogenesis.","evidence":"C-terminal capping stability screen, genetic/proteomic screens, CTLH/Muskelin knockout, and proteasome inhibitor assays (preprint)","pmids":["41648430"],"confidence":"Medium","gaps":["Signal transduction linking TNF-α/mTOR status to degron recognition unresolved","Preprint; ribosome biogenesis link not mechanistically detailed"]},{"year":null,"claim":"How ZMYND19's early-characterized roles (MCH-R1 binding, free-tubulin binding) integrate with its lysosomal mTORC1-regulatory function remains unknown.","evidence":"No timeline discovery connects the receptor/tubulin interactions to the CTLH-mTORC1 axis","pmids":[],"confidence":"Low","gaps":["Whether MCH-R1 or tubulin binding modulates ZMYND19 stability or mTORC1 inhibition is untested","No structural model of ZMYND19 itself","Endogenous physiological trigger for the mTORC1 brake undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[4,5]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[1]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[4,5]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[3]}],"complexes":[],"partners":["MCHR1","TUBA","TUBB","GID4","RPTOR","MKLN1","RHEB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96E35","full_name":"Zinc finger MYND domain-containing protein 19","aliases":["Melanin-concentrating hormone receptor 1-interacting zinc finger protein","MCH-R1-interacting zinc finger protein"],"length_aa":227,"mass_kda":26.4,"function":"May be involved as a regulatory molecule in GPR24/MCH-R1 signaling","subcellular_location":"Cytoplasm; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q96E35/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ZMYND19","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ZMYND19","total_profiled":1310},"omim":[{"mim_id":"611424","title":"ZINC FINGER MYND DOMAIN-CONTAINING PROTEIN 19; ZMYND19","url":"https://www.omim.org/entry/611424"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Vesicles","reliability":"Approved"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"retina","ntpm":267.2}],"url":"https://www.proteinatlas.org/search/ZMYND19"},"hgnc":{"alias_symbol":["MIZIP"],"prev_symbol":[]},"alphafold":{"accession":"Q96E35","domains":[{"cath_id":"-","chopping":"5-162","consensus_level":"high","plddt":86.0058,"start":5,"end":162}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96E35","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96E35-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96E35-F1-predicted_aligned_error_v6.png","plddt_mean":83.81},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ZMYND19","jax_strain_url":"https://www.jax.org/strain/search?query=ZMYND19"},"sequence":{"accession":"Q96E35","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96E35.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96E35/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96E35"}},"corpus_meta":[{"pmid":"34647674","id":"PMC_34647674","title":"The human GID complex engages two independent modules for substrate recruitment.","date":"2021","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/34647674","citation_count":42,"is_preprint":false},{"pmid":"29522715","id":"PMC_29522715","title":"LncRNA FABP5P3/miR-589-5p/ZMYND19 axis contributes to hepatocellular carcinoma cell proliferation, migration and invasion.","date":"2018","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/29522715","citation_count":18,"is_preprint":false},{"pmid":"12208518","id":"PMC_12208518","title":"MIZIP, a highly conserved, vertebrate specific melanin-concentrating hormone receptor 1 interacting zinc-finger protein.","date":"2002","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/12208518","citation_count":16,"is_preprint":false},{"pmid":"32731559","id":"PMC_32731559","title":"Decorin Protects Cardiac Myocytes against Simulated Ischemia/Reperfusion Injury.","date":"2020","source":"Molecules (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/32731559","citation_count":16,"is_preprint":false},{"pmid":"37428302","id":"PMC_37428302","title":"Identification of ZMYND19 as a novel biomarker of colorectal cancer: RNA-sequencing and machine learning analysis.","date":"2023","source":"Journal of cell communication and signaling","url":"https://pubmed.ncbi.nlm.nih.gov/37428302","citation_count":15,"is_preprint":false},{"pmid":"16039987","id":"PMC_16039987","title":"MYND domain specific interaction of the melanin-concentrating hormone receptor 1 interacting zinc-finger protein with alpha- and beta-tubulin.","date":"2005","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/16039987","citation_count":7,"is_preprint":false},{"pmid":"15950311","id":"PMC_15950311","title":"Immunohistochemical distribution of MIZIP and its co-expression with the Melanin-concentrating hormone receptor 1 in the adult rodent brain.","date":"2005","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/15950311","citation_count":6,"is_preprint":false},{"pmid":"38746323","id":"PMC_38746323","title":"The CTLH Ubiquitin Ligase Substrates ZMYND19 and MKLN1 Negatively Regulate mTORC1 at the Lysosomal Membrane.","date":"2024","source":"Research square","url":"https://pubmed.ncbi.nlm.nih.gov/38746323","citation_count":3,"is_preprint":false},{"pmid":"41315365","id":"PMC_41315365","title":"The CTLH ubiquitin ligase substrates ZMYND19 and MKLN1 negatively regulate mTORC1 at the lysosomal membrane.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/41315365","citation_count":2,"is_preprint":false},{"pmid":"41648430","id":"PMC_41648430","title":"Proteome-wide C-degron activity profiling connects conditional regulation of the CTLH E3 ligase complex to ribosome biogenesis.","date":"2026","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/41648430","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":6912,"output_tokens":2031,"usd":0.025601,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8930,"output_tokens":2907,"usd":0.058662,"stage2_stop_reason":"end_turn"},"total_usd":0.084263,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"MIZIP (ZMYND19) was identified as a binding partner of the C-terminus of melanin-concentrating hormone receptor 1 (MCH-R1). The interaction was verified by overlay assay, pull-down assay, and co-transfection experiments in HEK-293 cells. MIZIP is cytoplasmically localized but is recruited to the plasma membrane upon co-expression with MCH-R1.\",\n      \"method\": \"Yeast two-hybrid, overlay assay, GST pull-down, co-transfection/co-immunoprecipitation in HEK-293 cells, subcellular localization imaging\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — multiple orthogonal methods (Y2H, pull-down, co-IP, localization) in single lab\",\n      \"pmids\": [\"12208518\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"MIZIP (ZMYND19) interacts with alpha- and beta-tubulin via its MYND zinc-finger domain; the interaction maps to the N-terminus of tubulin. MIZIP binds to free tubulin but not to assembled microtubules in vivo, and ectopic MIZIP expression does not disrupt the overall microtubular cytoskeleton.\",\n      \"method\": \"Affinity purification from human cells, GST pull-down (in vitro), co-immunoprecipitation (in vivo), immunocytochemistry, domain-mapping experiments\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — reciprocal co-IP and pull-down with domain mapping, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"16039987\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"MIZIP (ZMYND19) is present in cytoplasmic, membrane, and synaptosomal fractions of adult mouse brain (but not postsynaptic density). In cultured rat embryonic hippocampal neurons, MIZIP is somatodendritically localized. Co-expression with MCH-R1 is observed in multiple brain regions, supporting cell-type-specific interaction in vivo.\",\n      \"method\": \"Subcellular fractionation of adult mouse brain, immunoblotting, immunohistochemistry, immunofluorescence in cultured neurons\",\n      \"journal\": \"Brain research. Molecular brain research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — localization data from a single lab without functional consequence directly demonstrated\",\n      \"pmids\": [\"15950311\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"ZMYND19 is a substrate of the human GID (hGID/CTLH) E3 ubiquitin ligase complex, recruited via the adaptor subunit GID4. Notably, ZMYND19 lacks a canonical Pro/N-end degron, distinguishing it from other GID4-dependent substrates. ARMC8α regulates GID4 substrate binding and ligase activity, while ARMC8β assembles a stable complex unable to recruit GID4.\",\n      \"method\": \"Biochemical ubiquitination assays, cross-linking mass spectrometry, cryo-electron microscopy, reconstitution of hGID complex\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure, in vitro reconstitution, and biochemical assays in one rigorous study\",\n      \"pmids\": [\"34647674\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ZMYND19 (and MKLN1) are substrates of the CTLH/MAEA E3 ubiquitin ligase; upon MAEA knockout, ZMYND19 accumulates and associates with lysosomes to inhibit mTORC1. ZMYND19 and MKLN1 bind Raptor and RagA/C and block a late stage of mTORC1 activation (not its lysosomal recruitment), independently of the tuberous sclerosis complex.\",\n      \"method\": \"Genome-wide CRISPR/Cas9 screen, MAEA knockout, co-immunoprecipitation, lysosomal fractionation, mTORC1 activity assays\",\n      \"journal\": \"Research square (preprint)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR screen plus co-IP and functional assays, single lab, preprint (superseded by peer-reviewed version)\",\n      \"pmids\": [\"38746323\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ZMYND19, a CTLH E3 ligase substrate, accumulates at lysosome outer membranes upon MAEA knockout and, together with MKLN1, inhibits mTORC1 by blocking the interaction between mTORC1 and Rheb and between mTORC1 and its substrates S6K and 4E-BP1 — rather than preventing mTORC1 lysosomal recruitment. This defines a ubiquitin/proteasome-based mechanism for rapid tuning of mTORC1 activity.\",\n      \"method\": \"Genome-wide CRISPR/Cas9 screen, MAEA knockout, co-immunoprecipitation (Raptor, RagA/C, Rheb), lysosome fractionation, mTORC1 substrate phosphorylation assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — peer-reviewed, multiple orthogonal methods (CRISPR screen, co-IP, fractionation, kinase assays) establishing pathway position and molecular mechanism\",\n      \"pmids\": [\"41315365\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ZMYND19 harbors a C-terminal degron recognized by the Muskelin substrate adaptor of the CTLH E3 ligase complex. CTLH-Muskelin-mediated degradation of ZMYND19 is conditionally regulated: impaired by TNF-α stimulation and enhanced by mTOR inhibition. This C-degron pathway connects conditional CTLH regulation to control of cellular processes including ribosome biogenesis.\",\n      \"method\": \"C-terminal capping expression screen for stability, genetic and proteomic screens, CTLH/Muskelin knockout, proteasome inhibitor assays, quantitative proteomics\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic C-degron screen plus genetic/proteomic validation, single lab, preprint only\",\n      \"pmids\": [\"41648430\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"ZMYND19 (MIZIP) is a MYND zinc-finger protein that interacts with MCH-R1 and free tubulin via its MYND domain; it is a substrate of the CTLH/GID E3 ubiquitin ligase complex (recruited through the GID4 adaptor and degraded via a Muskelin-dependent C-degron pathway), and when it escapes degradation, ZMYND19 accumulates at lysosome outer membranes where it associates with MKLN1, Raptor, and RagA/C to block Rheb–mTORC1 interaction and mTORC1 substrate phosphorylation, thereby negatively regulating mTORC1 signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ZMYND19 (MIZIP) is a MYND zinc-finger protein that functions as a conditionally degraded substrate of the CTLH/GID E3 ubiquitin ligase and, when stabilized, as a negative regulator of mTORC1 signaling at the lysosome [#3, #5]. It was first identified as a cytoplasmic interactor of the C-terminus of melanin-concentrating hormone receptor 1 (MCH-R1), to which it is recruited at the plasma membrane upon receptor co-expression [#0], and it additionally binds free \\u03b1- and \\u03b2-tubulin through its MYND domain without associating with assembled microtubules [#1]. Mechanistically, ZMYND19 is recognized by the human GID/CTLH complex: it is captured via the GID4 adaptor despite lacking a canonical Pro/N-end degron [#3], and is also targeted through a C-terminal degron read by the Muskelin adaptor, a degradation route tuned by TNF-\\u03b1 and mTOR inhibition [#6]. When CTLH activity is lost, ZMYND19 escapes degradation and accumulates at lysosome outer membranes, where together with MKLN1 it binds Raptor and RagA/C and blocks the interactions of mTORC1 with Rheb and with its substrates S6K and 4E-BP1, inhibiting mTORC1 at a late activation step independently of the tuberous sclerosis complex and downstream of its lysosomal recruitment [#4, #5]. This places ZMYND19 in a ubiquitin/proteasome-based circuit for rapid tuning of mTORC1 activity and associated processes such as ribosome biogenesis [#5, #6].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established ZMYND19's first physical partner, linking the orphan protein to G-protein-coupled receptor signaling by showing it binds the MCH-R1 C-terminus and is recruited to the membrane.\",\n      \"evidence\": \"Yeast two-hybrid, overlay/GST pull-down, and co-IP with localization imaging in HEK-293 cells\",\n      \"pmids\": [\"12208518\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of the MCH-R1 interaction on receptor signaling not determined\", \"Binding shown only in heterologous overexpression\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined the MYND domain as a protein-interaction module by mapping tubulin binding to it, revealing ZMYND19 binds free but not polymerized tubulin.\",\n      \"evidence\": \"Affinity purification, in vitro GST pull-down, in vivo co-IP, and domain-mapping in human cells\",\n      \"pmids\": [\"16039987\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Biological role of tubulin binding unresolved \\u2014 no microtubule phenotype observed\", \"Single lab, no orthogonal structural confirmation\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Provided native-tissue context by documenting ZMYND19 distribution and MCH-R1 co-expression in brain, supporting physiological relevance of the interaction.\",\n      \"evidence\": \"Subcellular fractionation, immunoblotting, and immunofluorescence in mouse brain and rat hippocampal neurons\",\n      \"pmids\": [\"15950311\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Localization data without demonstrated functional consequence\", \"No direct in vivo interaction assay in neurons\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified ZMYND19 as a bona fide CTLH/GID E3 ligase substrate and showed it is recruited atypically via GID4 without a canonical Pro/N-end degron, expanding the substrate logic of this ligase.\",\n      \"evidence\": \"In vitro ubiquitination, cross-linking mass spectrometry, cryo-EM, and reconstitution of the hGID complex\",\n      \"pmids\": [\"34647674\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"The actual degron motif on ZMYND19 recognized in this pathway not defined\", \"Cellular consequence of ZMYND19 turnover not addressed\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connected ZMYND19 turnover to a function by showing that upon CTLH/MAEA loss it accumulates at lysosomes and, with MKLN1, binds Raptor and RagA/C to inhibit mTORC1 at a late, TSC-independent activation step.\",\n      \"evidence\": \"Genome-wide CRISPR screen, MAEA knockout, co-IP, lysosomal fractionation, and mTORC1 activity assays (preprint)\",\n      \"pmids\": [\"38746323\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Precise molecular block on mTORC1 not yet defined in this version\", \"Preprint stage\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved the molecular mechanism of inhibition: stabilized ZMYND19/MKLN1 blocks mTORC1 binding to Rheb and to substrates S6K and 4E-BP1, defining a ubiquitin/proteasome circuit for rapid mTORC1 tuning.\",\n      \"evidence\": \"CRISPR screen, MAEA knockout, co-IP (Raptor, RagA/C, Rheb), lysosome fractionation, and substrate phosphorylation assays\",\n      \"pmids\": [\"41315365\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological stimulus that normally stabilizes ZMYND19 to engage this brake not established\", \"Structural basis of the Rheb/substrate block unknown\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Identified a conditional C-degron pathway, showing ZMYND19 is degraded via the Muskelin adaptor of CTLH in a manner tuned by TNF-\\u03b1 and mTOR inhibition, linking ligase regulation to ribosome biogenesis.\",\n      \"evidence\": \"C-terminal capping stability screen, genetic/proteomic screens, CTLH/Muskelin knockout, and proteasome inhibitor assays (preprint)\",\n      \"pmids\": [\"41648430\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signal transduction linking TNF-\\u03b1/mTOR status to degron recognition unresolved\", \"Preprint; ribosome biogenesis link not mechanistically detailed\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How ZMYND19's early-characterized roles (MCH-R1 binding, free-tubulin binding) integrate with its lysosomal mTORC1-regulatory function remains unknown.\",\n      \"evidence\": \"No timeline discovery connects the receptor/tubulin interactions to the CTLH-mTORC1 axis\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Whether MCH-R1 or tubulin binding modulates ZMYND19 stability or mTORC1 inhibition is untested\", \"No structural model of ZMYND19 itself\", \"Endogenous physiological trigger for the mTORC1 brake undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [4, 5]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [4, 5]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"MCHR1\", \"TUBA\", \"TUBB\", \"GID4\", \"RPTOR\", \"MKLN1\", \"RHEB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}