{"gene":"TMEM74","run_date":"2026-04-28T21:42:59","timeline":{"discoveries":[{"year":2008,"finding":"TMEM74 localizes to lysosomes and autophagosomes; overexpression in HeLa cells induces autophagic vacuolization, increases MDC and GFP-LC3 dot formation, and elevates LC3-II levels; these effects are partially blocked by the PI3K inhibitor wortmannin; siRNA knockdown of TMEM74 abolishes starvation-induced autophagy.","method":"Subcellular fractionation/immunofluorescence localization, GFP-LC3 fluorescence microscopy, MDC staining, immunoblotting for LC3-II, siRNA knockdown, pharmacological inhibition (wortmannin)","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (localization, GFP-LC3 dots, LC3-II immunoblot, siRNA KD) in single foundational paper, replicated by subsequent studies","pmids":["18294959"],"is_preprint":false},{"year":2009,"finding":"Overexpression of TMEM74 induces high levels of autophagosome formation as identified in a high-throughput functional screen of 1,050 human cDNA clones using GFP-LC3 dot quantification.","method":"High-throughput automated fluorescence microscopy screen (GFP-LC3), transmission electron microscopy, immunoblotting for LC3-II","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 — independent replication of autophagy-inducing activity from a separate lab using orthogonal screen","pmids":["19029833"],"is_preprint":false},{"year":2017,"finding":"TMEM74 promotes autophagy via direct physical interactions with ATG16L1 (involved in autophagosome nucleation) and ATG9A (involved in membrane elongation); this autophagy pathway is independent of BECN1/PI3KC3 complex and ULK1; TMEM74-induced autophagy has a pro-survival effect on tumor cells under metabolic stress; TMEM74 itself is degraded through the autophagic process, forming a self-regulatory loop.","method":"Co-immunoprecipitation, immunoblotting, GFP-LC3 fluorescence microscopy, siRNA knockdown of ATG16L1 and ATG9A, cell viability assays under metabolic stress, autophagy flux assays","journal":"Cell death & disease","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP identifying binding partners ATG16L1 and ATG9A, epistasis via siRNA knockdown of interaction partners, multiple functional readouts","pmids":["29048433"],"is_preprint":false},{"year":2017,"finding":"TMEM74 co-localizes with the pro-apoptotic protein BIK in subcellular organelles and physically interacts with BIK via TMEM74's transmembrane (TM) domains and BIK's BH3 domain; this interaction inhibits BIK-induced apoptosis independently of autophagosome formation; TM domain-deficient TMEM74 mutants lose this inhibitory function.","method":"Co-immunoprecipitation, immunofluorescence co-localization, domain-deletion mutagenesis, apoptosis assays (caspase activation, cell death), autophagosome formation inhibitor controls","journal":"Cellular signalling","confidence":"High","confidence_rationale":"Tier 1–2 — Co-IP with mutagenesis (TM domain deletions) and functional apoptosis assays validating the mechanistic interaction","pmids":["28412412"],"is_preprint":false},{"year":2019,"finding":"TMEM74 physically interacts with HCN1 channels in basolateral amygdala (BLA) pyramidal neurons; this interaction promotes surface expression/trafficking of HCN1 and enhances hyperpolarization-activated cation current (Ih); TMEM74 transmembrane domain 1 (TM1) is essential for TMEM74's membrane localization and its ability to enhance Ih; genetic deletion or selective BLA knockdown of Tmem74 reduces Ih, increases neuronal excitability, and produces anxiety-like behavior in mice; Tmem74 overexpression restores HCN1 trafficking and neuronal excitability.","method":"Co-immunoprecipitation, whole-cell patch-clamp electrophysiology (Ih current recording), surface biotinylation assay, domain-deletion mutagenesis (TM1), conditional BLA-specific knockdown (AAV-shRNA), Tmem74 knockout mice, behavioral testing","journal":"Molecular psychiatry","confidence":"High","confidence_rationale":"Tier 1–2 — Co-IP identifying binding partner, domain mutagenesis, electrophysiology, surface expression assay, and in vivo behavioral rescue, multiple orthogonal methods in one study","pmids":["30886335"],"is_preprint":false},{"year":2023,"finding":"Conditional deletion of Tmem74 in prelimbic cortex (PL) pyramidal neurons increases their excitability; alterations in PL projections to fast-spiking interneurons (FSIs) in the dorsal striatum (PLPNs→dSTRFSIs) mediate autism-like behaviors, while alterations in PL projections to basolateral amygdala pyramidal neurons (PLPNs→BLAPNs) mediate anxiety-like behaviors; both phenotypes are reversed by Tmem74 re-expression or chemogenetic inhibition of PL pyramidal neurons.","method":"Tmem74 knockout mice, conditional/regional deletion (AAV-Cre in PL), optogenetic circuit manipulation, chemogenetic (DREADD) inhibition, whole-cell patch-clamp electrophysiology, behavioral testing (autism and anxiety assays)","journal":"Molecular psychiatry","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis with circuit-level dissection using optogenetics and chemogenetics, multiple behavioral and electrophysiological readouts, rescue experiments","pmids":["36690791"],"is_preprint":false}],"current_model":"TMEM74 is a lysosome/autophagosome transmembrane protein that promotes autophagy by directly interacting (via its TM domains) with ATG16L1 and ATG9A independently of the BECN1/PI3KC3 and ULK1 pathway; it also interacts with BIK (via BH3 domain) to inhibit apoptosis, and in neurons it physically couples with HCN1 channels to promote their surface trafficking and enhance Ih current, thereby controlling neuronal excitability in circuits underlying anxiety and autism-like behaviors."},"narrative":{"teleology":[{"year":2008,"claim":"The first functional characterization established that TMEM74 is a lysosome/autophagosome-resident protein whose overexpression is sufficient and whose knockdown is necessary for starvation-induced autophagy, placing it as a positive regulator of this pathway.","evidence":"Subcellular fractionation, GFP-LC3 dot formation, MDC staining, LC3-II immunoblotting, siRNA knockdown, and wortmannin inhibition in HeLa cells","pmids":["18294959"],"confidence":"High","gaps":["No direct binding partners identified","Mechanism of action within the autophagy cascade unknown","Partial wortmannin sensitivity left the PI3K-dependence ambiguous"]},{"year":2009,"claim":"An independent high-throughput screen confirmed TMEM74 as one of the strongest autophagy inducers among >1,000 human cDNAs, providing unbiased validation of its autophagy-promoting activity.","evidence":"Automated GFP-LC3 dot quantification screen, TEM, and LC3-II immunoblotting","pmids":["19029833"],"confidence":"Medium","gaps":["Screen-level data without detailed mechanistic follow-up","Binding partners and pathway position still undefined"]},{"year":2017,"claim":"The mechanistic basis of TMEM74-driven autophagy was resolved: TMEM74 directly binds ATG16L1 and ATG9A to promote autophagosome formation independently of BECN1/PI3KC3 and ULK1, and is itself degraded by autophagy, forming a negative-feedback loop that confers pro-survival advantage under metabolic stress.","evidence":"Reciprocal co-immunoprecipitation, siRNA epistasis for ATG16L1 and ATG9A, GFP-LC3 microscopy, autophagy flux assays, and cell viability assays under stress","pmids":["29048433"],"confidence":"High","gaps":["Structural details of the TMEM74–ATG16L1 and TMEM74–ATG9A interfaces unknown","Whether TMEM74 functions as a scaffold or an activator of these partners is unresolved","In vivo relevance of the BECN1/ULK1-independent pathway not tested"]},{"year":2017,"claim":"A second, autophagy-independent function was uncovered: TMEM74 physically interacts with the pro-apoptotic BH3-only protein BIK through its transmembrane domains to suppress BIK-induced apoptosis, establishing TMEM74 as a dual regulator of autophagy and apoptosis.","evidence":"Co-immunoprecipitation, co-localization imaging, TM domain-deletion mutagenesis, and caspase/cell death apoptosis assays","pmids":["28412412"],"confidence":"High","gaps":["Whether TMEM74 sequesters BIK or alters its conformation is unknown","Physiological context (cell type, stress condition) for the anti-apoptotic function not defined","Relationship between autophagy and apoptosis arms at endogenous expression levels unclear"]},{"year":2019,"claim":"A neuronal role was established: TMEM74 binds HCN1 channels and promotes their surface trafficking, enhancing Ih current in basolateral amygdala pyramidal neurons; loss of TMEM74 increases excitability and produces anxiety-like behavior, revealing a non-autophagic in vivo function.","evidence":"Co-immunoprecipitation, surface biotinylation, TM1 domain deletion, whole-cell patch-clamp, Tmem74 knockout mice, BLA-specific AAV-shRNA knockdown, and behavioral rescue","pmids":["30886335"],"confidence":"High","gaps":["Whether TMEM74 chaperones HCN1 through the secretory pathway or stabilizes it at the plasma membrane is unresolved","Interaction interface on HCN1 not mapped","Whether this trafficking function extends to other HCN family members unknown"]},{"year":2023,"claim":"Circuit-level dissection showed that TMEM74 loss in prelimbic cortex pyramidal neurons increases excitability and produces dissociable behavioral phenotypes—autism-like behaviors via projections to dorsal striatum fast-spiking interneurons and anxiety-like behaviors via projections to BLA—establishing TMEM74 as a cell-autonomous regulator of neuronal excitability with circuit-specific behavioral outputs.","evidence":"Conditional Tmem74 deletion in PL (AAV-Cre), optogenetic and chemogenetic circuit manipulation, whole-cell patch-clamp, and multi-domain behavioral testing with rescue","pmids":["36690791"],"confidence":"High","gaps":["Whether HCN1 trafficking is the sole mechanism underlying excitability changes in PL neurons is untested","Molecular partners mediating TMEM74 function in cortical (vs. amygdala) neurons not identified","Human genetic association with anxiety or autism spectrum disorder not established"]},{"year":null,"claim":"Key unresolved questions include the structural basis of TMEM74's interactions with ATG16L1, ATG9A, BIK, and HCN1; whether its autophagy and ion channel trafficking functions are mechanistically linked or fully independent; and whether TMEM74 variants contribute to human neuropsychiatric disease.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural data for any TMEM74 complex","No human genetic evidence linking TMEM74 to disease","Relationship between autophagy/apoptosis function and neuronal trafficking function unexplored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,3,4]}],"localization":[{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[0]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[3]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[4,5]}],"complexes":[],"partners":["ATG16L1","ATG9A","BIK","HCN1"],"other_free_text":[]},"mechanistic_narrative":"TMEM74 is a multi-pass transmembrane protein that functions at the intersection of autophagy, apoptosis regulation, and neuronal excitability. It localizes to lysosomes and autophagosomes and promotes autophagy through direct physical interactions with ATG16L1 and ATG9A via a BECN1/PI3KC3- and ULK1-independent pathway, with TMEM74 itself undergoing autophagic degradation in a self-regulatory loop [PMID:18294959, PMID:29048433]. Independently of its autophagy function, TMEM74 inhibits BIK-mediated apoptosis through a transmembrane domain–BH3 domain interaction, and it promotes surface trafficking of HCN1 channels in neurons, enhancing Ih current and restraining neuronal excitability in amygdala and prefrontal cortical circuits that govern anxiety- and autism-like behaviors [PMID:28412412, PMID:30886335, PMID:36690791]."},"prefetch_data":{"uniprot":{"accession":"Q96NL1","full_name":"Transmembrane protein 74","aliases":[],"length_aa":305,"mass_kda":33.3,"function":"Plays an essential role in autophagy. TMEM74-induced autophagy may involve PI3K signal transduction","subcellular_location":"Lysosome membrane; Cytoplasmic vesicle, autophagosome membrane","url":"https://www.uniprot.org/uniprotkb/Q96NL1/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TMEM74","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/TMEM74","total_profiled":1310},"omim":[{"mim_id":"613935","title":"TRANSMEMBRANE PROTEIN 74; TMEM74","url":"https://www.omim.org/entry/613935"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":2.7},{"tissue":"retina","ntpm":2.3}],"url":"https://www.proteinatlas.org/search/TMEM74"},"hgnc":{"alias_symbol":["FLJ30668","NET36"],"prev_symbol":[]},"alphafold":{"accession":"Q96NL1","domains":[{"cath_id":"1.10.287","chopping":"174-201_217-269","consensus_level":"medium","plddt":77.2753,"start":174,"end":269}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96NL1","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96NL1-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96NL1-F1-predicted_aligned_error_v6.png","plddt_mean":56.97},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TMEM74","jax_strain_url":"https://www.jax.org/strain/search?query=TMEM74"},"sequence":{"accession":"Q96NL1","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96NL1.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96NL1/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96NL1"}},"corpus_meta":[{"pmid":"19029833","id":"PMC_19029833","title":"High-throughput functional screening for autophagy-related genes and identification of TM9SF1 as an autophagosome-inducing gene.","date":"2009","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/19029833","citation_count":73,"is_preprint":false},{"pmid":"18294959","id":"PMC_18294959","title":"TMEM74, a lysosome and autophagosome protein, regulates autophagy.","date":"2008","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/18294959","citation_count":51,"is_preprint":false},{"pmid":"23759441","id":"PMC_23759441","title":"Lithium treatment increases endothelial cell survival and autophagy in a mouse model of Fuchs endothelial corneal dystrophy.","date":"2013","source":"The British journal of ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/23759441","citation_count":46,"is_preprint":false},{"pmid":"37936608","id":"PMC_37936608","title":"The transmembrane proteins (TMEM) and their role in cell proliferation, migration, invasion, and epithelial-mesenchymal transition in cancer.","date":"2023","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/37936608","citation_count":38,"is_preprint":false},{"pmid":"24034811","id":"PMC_24034811","title":"Methylation profiling and evaluation of demethylating therapy in renal cell carcinoma.","date":"2013","source":"Clinical epigenetics","url":"https://pubmed.ncbi.nlm.nih.gov/24034811","citation_count":32,"is_preprint":false},{"pmid":"36690791","id":"PMC_36690791","title":"Divergent projections of the prelimbic cortex mediate autism- and anxiety-like behaviors.","date":"2023","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/36690791","citation_count":26,"is_preprint":false},{"pmid":"29048433","id":"PMC_29048433","title":"TMEM74 promotes tumor cell survival by inducing autophagy via interactions with ATG16L1 and ATG9A.","date":"2017","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/29048433","citation_count":23,"is_preprint":false},{"pmid":"30886335","id":"PMC_30886335","title":"Functional coupling of Tmem74 and HCN1 channels regulates anxiety-like behavior in BLA neurons.","date":"2019","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/30886335","citation_count":20,"is_preprint":false},{"pmid":"33011366","id":"PMC_33011366","title":"SANT, a novel Chinese herbal monomer combination, decreasing tumor growth and angiogenesis via modulating autophagy in heparanase overexpressed triple-negative breast cancer.","date":"2020","source":"Journal of ethnopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/33011366","citation_count":19,"is_preprint":false},{"pmid":"28412412","id":"PMC_28412412","title":"Autophagy regulatory molecule, TMEM74, interacts with BIK and inhibits BIK-induced apoptosis.","date":"2017","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/28412412","citation_count":15,"is_preprint":false},{"pmid":"29629952","id":"PMC_29629952","title":"The Expression of TMEM74 in Liver Cancer and Lung Cancer Correlating With Survival Outcomes.","date":"2019","source":"Applied immunohistochemistry & molecular morphology : AIMM","url":"https://pubmed.ncbi.nlm.nih.gov/29629952","citation_count":10,"is_preprint":false},{"pmid":"31560972","id":"PMC_31560972","title":"Mycophenolic acid (MPA) modulates host cellular autophagy progression in sub genomic dengue virus-2 replicon cells.","date":"2019","source":"Microbial pathogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/31560972","citation_count":9,"is_preprint":false},{"pmid":"34132174","id":"PMC_34132174","title":"Genome-wide association study detected novel susceptibility genes for social cognition impairment in people with schizophrenia.","date":"2021","source":"The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/34132174","citation_count":8,"is_preprint":false},{"pmid":"33236465","id":"PMC_33236465","title":"Super-variants identification for brain connectivity.","date":"2020","source":"Human brain mapping","url":"https://pubmed.ncbi.nlm.nih.gov/33236465","citation_count":7,"is_preprint":false},{"pmid":"38276004","id":"PMC_38276004","title":"Rapamycin as a Potential Alternative Drug for Squamous Cell Gingiva Carcinoma (Ca9-22): A Focus on Cell Cycle, Apoptosis and Autophagy Genetic Profile.","date":"2024","source":"Pharmaceuticals (Basel, Switzerland)","url":"https://pubmed.ncbi.nlm.nih.gov/38276004","citation_count":3,"is_preprint":false},{"pmid":"37690223","id":"PMC_37690223","title":"High-throughput screening and clinical importance of autophagy-associated genes in basal cell carcinoma.","date":"2023","source":"Pathology, research and practice","url":"https://pubmed.ncbi.nlm.nih.gov/37690223","citation_count":2,"is_preprint":false},{"pmid":"40644891","id":"PMC_40644891","title":"Biomarker discovery for early breast cancer diagnosis using machine learning on transcriptomic data for biosensor development.","date":"2025","source":"Computers in biology and medicine","url":"https://pubmed.ncbi.nlm.nih.gov/40644891","citation_count":2,"is_preprint":false},{"pmid":"41436842","id":"PMC_41436842","title":"Transcriptomic decoding of regional cortical vulnerability to drug-resistant epilepsy using 7T MRI.","date":"2025","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/41436842","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11321,"output_tokens":1843,"usd":0.030804},"stage2":{"model":"claude-opus-4-6","input_tokens":5088,"output_tokens":2145,"usd":0.118597},"total_usd":0.149401,"stage1_batch_id":"msgbatch_01RPbVc9PDH9zQmYK5Hs6srm","stage2_batch_id":"msgbatch_01JVbVLzeKN2yVrsGp3zC8aM","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"TMEM74 localizes to lysosomes and autophagosomes; overexpression in HeLa cells induces autophagic vacuolization, increases MDC and GFP-LC3 dot formation, and elevates LC3-II levels; these effects are partially blocked by the PI3K inhibitor wortmannin; siRNA knockdown of TMEM74 abolishes starvation-induced autophagy.\",\n      \"method\": \"Subcellular fractionation/immunofluorescence localization, GFP-LC3 fluorescence microscopy, MDC staining, immunoblotting for LC3-II, siRNA knockdown, pharmacological inhibition (wortmannin)\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (localization, GFP-LC3 dots, LC3-II immunoblot, siRNA KD) in single foundational paper, replicated by subsequent studies\",\n      \"pmids\": [\"18294959\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Overexpression of TMEM74 induces high levels of autophagosome formation as identified in a high-throughput functional screen of 1,050 human cDNA clones using GFP-LC3 dot quantification.\",\n      \"method\": \"High-throughput automated fluorescence microscopy screen (GFP-LC3), transmission electron microscopy, immunoblotting for LC3-II\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — independent replication of autophagy-inducing activity from a separate lab using orthogonal screen\",\n      \"pmids\": [\"19029833\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TMEM74 promotes autophagy via direct physical interactions with ATG16L1 (involved in autophagosome nucleation) and ATG9A (involved in membrane elongation); this autophagy pathway is independent of BECN1/PI3KC3 complex and ULK1; TMEM74-induced autophagy has a pro-survival effect on tumor cells under metabolic stress; TMEM74 itself is degraded through the autophagic process, forming a self-regulatory loop.\",\n      \"method\": \"Co-immunoprecipitation, immunoblotting, GFP-LC3 fluorescence microscopy, siRNA knockdown of ATG16L1 and ATG9A, cell viability assays under metabolic stress, autophagy flux assays\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP identifying binding partners ATG16L1 and ATG9A, epistasis via siRNA knockdown of interaction partners, multiple functional readouts\",\n      \"pmids\": [\"29048433\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"TMEM74 co-localizes with the pro-apoptotic protein BIK in subcellular organelles and physically interacts with BIK via TMEM74's transmembrane (TM) domains and BIK's BH3 domain; this interaction inhibits BIK-induced apoptosis independently of autophagosome formation; TM domain-deficient TMEM74 mutants lose this inhibitory function.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence co-localization, domain-deletion mutagenesis, apoptosis assays (caspase activation, cell death), autophagosome formation inhibitor controls\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — Co-IP with mutagenesis (TM domain deletions) and functional apoptosis assays validating the mechanistic interaction\",\n      \"pmids\": [\"28412412\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"TMEM74 physically interacts with HCN1 channels in basolateral amygdala (BLA) pyramidal neurons; this interaction promotes surface expression/trafficking of HCN1 and enhances hyperpolarization-activated cation current (Ih); TMEM74 transmembrane domain 1 (TM1) is essential for TMEM74's membrane localization and its ability to enhance Ih; genetic deletion or selective BLA knockdown of Tmem74 reduces Ih, increases neuronal excitability, and produces anxiety-like behavior in mice; Tmem74 overexpression restores HCN1 trafficking and neuronal excitability.\",\n      \"method\": \"Co-immunoprecipitation, whole-cell patch-clamp electrophysiology (Ih current recording), surface biotinylation assay, domain-deletion mutagenesis (TM1), conditional BLA-specific knockdown (AAV-shRNA), Tmem74 knockout mice, behavioral testing\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — Co-IP identifying binding partner, domain mutagenesis, electrophysiology, surface expression assay, and in vivo behavioral rescue, multiple orthogonal methods in one study\",\n      \"pmids\": [\"30886335\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Conditional deletion of Tmem74 in prelimbic cortex (PL) pyramidal neurons increases their excitability; alterations in PL projections to fast-spiking interneurons (FSIs) in the dorsal striatum (PLPNs→dSTRFSIs) mediate autism-like behaviors, while alterations in PL projections to basolateral amygdala pyramidal neurons (PLPNs→BLAPNs) mediate anxiety-like behaviors; both phenotypes are reversed by Tmem74 re-expression or chemogenetic inhibition of PL pyramidal neurons.\",\n      \"method\": \"Tmem74 knockout mice, conditional/regional deletion (AAV-Cre in PL), optogenetic circuit manipulation, chemogenetic (DREADD) inhibition, whole-cell patch-clamp electrophysiology, behavioral testing (autism and anxiety assays)\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with circuit-level dissection using optogenetics and chemogenetics, multiple behavioral and electrophysiological readouts, rescue experiments\",\n      \"pmids\": [\"36690791\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TMEM74 is a lysosome/autophagosome transmembrane protein that promotes autophagy by directly interacting (via its TM domains) with ATG16L1 and ATG9A independently of the BECN1/PI3KC3 and ULK1 pathway; it also interacts with BIK (via BH3 domain) to inhibit apoptosis, and in neurons it physically couples with HCN1 channels to promote their surface trafficking and enhance Ih current, thereby controlling neuronal excitability in circuits underlying anxiety and autism-like behaviors.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TMEM74 is a multi-pass transmembrane protein that functions at the intersection of autophagy, apoptosis regulation, and neuronal excitability. It localizes to lysosomes and autophagosomes and promotes autophagy through direct physical interactions with ATG16L1 and ATG9A via a BECN1/PI3KC3- and ULK1-independent pathway, with TMEM74 itself undergoing autophagic degradation in a self-regulatory loop [PMID:18294959, PMID:29048433]. Independently of its autophagy function, TMEM74 inhibits BIK-mediated apoptosis through a transmembrane domain–BH3 domain interaction, and it promotes surface trafficking of HCN1 channels in neurons, enhancing Ih current and restraining neuronal excitability in amygdala and prefrontal cortical circuits that govern anxiety- and autism-like behaviors [PMID:28412412, PMID:30886335, PMID:36690791].\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"The first functional characterization established that TMEM74 is a lysosome/autophagosome-resident protein whose overexpression is sufficient and whose knockdown is necessary for starvation-induced autophagy, placing it as a positive regulator of this pathway.\",\n      \"evidence\": \"Subcellular fractionation, GFP-LC3 dot formation, MDC staining, LC3-II immunoblotting, siRNA knockdown, and wortmannin inhibition in HeLa cells\",\n      \"pmids\": [\"18294959\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No direct binding partners identified\",\n        \"Mechanism of action within the autophagy cascade unknown\",\n        \"Partial wortmannin sensitivity left the PI3K-dependence ambiguous\"\n      ]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"An independent high-throughput screen confirmed TMEM74 as one of the strongest autophagy inducers among >1,000 human cDNAs, providing unbiased validation of its autophagy-promoting activity.\",\n      \"evidence\": \"Automated GFP-LC3 dot quantification screen, TEM, and LC3-II immunoblotting\",\n      \"pmids\": [\"19029833\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Screen-level data without detailed mechanistic follow-up\",\n        \"Binding partners and pathway position still undefined\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"The mechanistic basis of TMEM74-driven autophagy was resolved: TMEM74 directly binds ATG16L1 and ATG9A to promote autophagosome formation independently of BECN1/PI3KC3 and ULK1, and is itself degraded by autophagy, forming a negative-feedback loop that confers pro-survival advantage under metabolic stress.\",\n      \"evidence\": \"Reciprocal co-immunoprecipitation, siRNA epistasis for ATG16L1 and ATG9A, GFP-LC3 microscopy, autophagy flux assays, and cell viability assays under stress\",\n      \"pmids\": [\"29048433\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural details of the TMEM74–ATG16L1 and TMEM74–ATG9A interfaces unknown\",\n        \"Whether TMEM74 functions as a scaffold or an activator of these partners is unresolved\",\n        \"In vivo relevance of the BECN1/ULK1-independent pathway not tested\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"A second, autophagy-independent function was uncovered: TMEM74 physically interacts with the pro-apoptotic BH3-only protein BIK through its transmembrane domains to suppress BIK-induced apoptosis, establishing TMEM74 as a dual regulator of autophagy and apoptosis.\",\n      \"evidence\": \"Co-immunoprecipitation, co-localization imaging, TM domain-deletion mutagenesis, and caspase/cell death apoptosis assays\",\n      \"pmids\": [\"28412412\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TMEM74 sequesters BIK or alters its conformation is unknown\",\n        \"Physiological context (cell type, stress condition) for the anti-apoptotic function not defined\",\n        \"Relationship between autophagy and apoptosis arms at endogenous expression levels unclear\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"A neuronal role was established: TMEM74 binds HCN1 channels and promotes their surface trafficking, enhancing Ih current in basolateral amygdala pyramidal neurons; loss of TMEM74 increases excitability and produces anxiety-like behavior, revealing a non-autophagic in vivo function.\",\n      \"evidence\": \"Co-immunoprecipitation, surface biotinylation, TM1 domain deletion, whole-cell patch-clamp, Tmem74 knockout mice, BLA-specific AAV-shRNA knockdown, and behavioral rescue\",\n      \"pmids\": [\"30886335\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether TMEM74 chaperones HCN1 through the secretory pathway or stabilizes it at the plasma membrane is unresolved\",\n        \"Interaction interface on HCN1 not mapped\",\n        \"Whether this trafficking function extends to other HCN family members unknown\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Circuit-level dissection showed that TMEM74 loss in prelimbic cortex pyramidal neurons increases excitability and produces dissociable behavioral phenotypes—autism-like behaviors via projections to dorsal striatum fast-spiking interneurons and anxiety-like behaviors via projections to BLA—establishing TMEM74 as a cell-autonomous regulator of neuronal excitability with circuit-specific behavioral outputs.\",\n      \"evidence\": \"Conditional Tmem74 deletion in PL (AAV-Cre), optogenetic and chemogenetic circuit manipulation, whole-cell patch-clamp, and multi-domain behavioral testing with rescue\",\n      \"pmids\": [\"36690791\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether HCN1 trafficking is the sole mechanism underlying excitability changes in PL neurons is untested\",\n        \"Molecular partners mediating TMEM74 function in cortical (vs. amygdala) neurons not identified\",\n        \"Human genetic association with anxiety or autism spectrum disorder not established\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of TMEM74's interactions with ATG16L1, ATG9A, BIK, and HCN1; whether its autophagy and ion channel trafficking functions are mechanistically linked or fully independent; and whether TMEM74 variants contribute to human neuropsychiatric disease.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural data for any TMEM74 complex\",\n        \"No human genetic evidence linking TMEM74 to disease\",\n        \"Relationship between autophagy/apoptosis function and neuronal trafficking function unexplored\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"ATG16L1\",\n      \"ATG9A\",\n      \"BIK\",\n      \"HCN1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}