{"gene":"RAB5IF","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2025,"finding":"RAB5IF silencing in retinal microvascular endothelial cells impeded mitochondrial respiration and ribosome biogenesis, specifically suppressing SUMO2 mRNA translation initiation and consequently lowering SUMO2 protein levels, defining RAB5IF as an upstream regulator of SUMO2 expression at the translational level.","method":"Proteomic sequencing, gene silencing (siRNA/shRNA), Western blot, mitochondrial respiration assay, in vivo retinal angiogenesis models (oxygen-induced retinopathy, laser-induced choroidal neovascularization in mice)","journal":"Nature Communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (proteomics, KD, in vivo models, functional assays) in a single rigorous study with clear mechanistic pathway delineation","pmids":["41390488"],"is_preprint":false},{"year":2025,"finding":"RAB5IF is required for physiological retinal vascular development and pathological retinal angiogenesis; endothelial-specific loss of RAB5IF suppressed VEGF signaling through reduction of SUMO2, which is required for SUMOylation of Gαi1/3 at Lys277, and Gαi1/3 SUMOylation is necessary for VEGF-induced signaling and pro-angiogenic activity.","method":"In vivo knockout/silencing in mouse retinal angiogenesis models, mutagenesis of Gαi1/3 SUMOylation sites, VEGF signaling assays, co-immunoprecipitation of TrkB-SUMO2-Gαi1/3 complexes","journal":"Nature Communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal functional validation with mutagenesis, in vivo models, and multiple orthogonal assays in one study","pmids":["41390488"],"is_preprint":false},{"year":2026,"finding":"In hippocampal neurons, RAB5IF promotes BDNF/TrkB signaling by maintaining translational efficiency of Sumo2 mRNA; RAB5IF silencing or knockout reduces SUMO2 protein, impairs SUMOylation of Gαi1/3 at Lys277, and disrupts formation of TrkB-SUMO2-Gαi1/3 signaling complexes required for downstream Akt-mTOR activation.","method":"Neuronal RAB5IF knockdown and conditional knockout in mouse hippocampus, overexpression rescue, site-directed mutagenesis of Gαi1/3 SUMOylation sites, co-immunoprecipitation, BDNF signaling assays, dendritic morphology and synaptic density quantification","journal":"Science Signaling","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — mutagenesis, KO rescue, co-IP, multiple in vitro and in vivo orthogonal methods establishing mechanistic pathway","pmids":["41915731"],"is_preprint":false},{"year":2026,"finding":"RAB5IF knockdown or conditional knockout in mouse hippocampus impairs mitochondrial function and dendritic branching/synaptic density in neurons, and induces depressive-like behaviors; conversely, RAB5IF overexpression in hippocampus mitigates depressive phenotype caused by chronic mild stress.","method":"Conditional knockout and AAV-mediated overexpression/knockdown in mouse hippocampus, behavioral assays (depressive-like behavior), mitochondrial function assays, dendritic morphology quantification in cultured hippocampal neurons","journal":"Science Signaling","confidence":"High","confidence_rationale":"Tier 2 / Strong — gain- and loss-of-function in vivo with defined cellular and behavioral phenotypes, replicated across multiple approaches in one study","pmids":["41915731"],"is_preprint":false},{"year":2025,"finding":"RAB5IF knockdown in NSCLC cell lines inhibited cell viability, proliferation, and migration, and impaired mitochondrial function; overexpression promoted proliferation and migration; these effects were mediated through the AKT-mTOR pathway, confirmed both in vitro and in vivo in xenograft models.","method":"Lentiviral knockdown and overexpression in NSCLC cell lines, Western blot (AKT-mTOR pathway), cell viability/proliferation/migration assays, mitochondrial function assays, nude mouse xenograft models","journal":"Cancer Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal gain/loss-of-function with pathway validation, single lab, in vivo confirmation but limited mechanistic depth","pmids":["40318299"],"is_preprint":false}],"current_model":"RAB5IF is a mitochondrial protein that promotes ribosome biogenesis and mitochondrial respiration to support translational efficiency of SUMO2 mRNA; elevated SUMO2 protein then SUMOylates Gαi1/3 at Lys277, enabling assembly of TrkB-SUMO2-Gαi1/3 signaling complexes that activate downstream Akt-mTOR signaling in response to VEGF and BDNF, thereby driving retinal angiogenesis and neuronal resilience against depressive stimuli, while also promoting NSCLC cell proliferation and migration via the AKT-mTOR pathway."},"narrative":{"mechanistic_narrative":"RAB5IF is a mitochondrial protein that couples mitochondrial respiration and ribosome biogenesis to a SUMO2-dependent signaling axis governing angiogenesis, neuronal resilience, and tumor cell growth [PMID:41390488, PMID:41915731]. Mechanistically, RAB5IF sustains the translational efficiency of SUMO2 mRNA, and loss of RAB5IF lowers SUMO2 protein levels by suppressing SUMO2 translation initiation [PMID:41390488, PMID:41915731]. The resulting SUMO2 is required for SUMOylation of Gαi1/3 at Lys277, which licenses assembly of TrkB-SUMO2-Gαi1/3 signaling complexes and downstream Akt-mTOR activation in response to VEGF and BDNF [PMID:41390488, PMID:41915731]. Through this axis, endothelial RAB5IF is required for physiological and pathological retinal angiogenesis [PMID:41390488], hippocampal RAB5IF supports dendritic branching, synaptic density, and protection against depressive-like behavior [PMID:41915731], and in NSCLC cells RAB5IF promotes proliferation and migration via the AKT-mTOR pathway [PMID:40318299]. Across these settings, RAB5IF function is consistently tied to maintenance of mitochondrial function [PMID:41390488, PMID:41915731, PMID:40318299].","teleology":[{"year":2025,"claim":"Established that RAB5IF acts upstream of SUMO2 at the translational level by linking mitochondrial respiration and ribosome biogenesis to SUMO2 mRNA translation initiation, defining the entry point of its mechanism.","evidence":"Proteomic sequencing, gene silencing, Western blot, and mitochondrial respiration assays in retinal microvascular endothelial cells","pmids":["41390488"],"confidence":"High","gaps":["The molecular mechanism by which RAB5IF selectively controls SUMO2 mRNA translation initiation is not defined","Whether RAB5IF directly binds ribosomal components or SUMO2 mRNA is not shown"]},{"year":2025,"claim":"Connected the RAB5IF-SUMO2 axis to VEGF signaling by showing SUMO2-dependent SUMOylation of Gαi1/3 at Lys277 and assembly of TrkB-SUMO2-Gαi1/3 complexes are required for pro-angiogenic activity.","evidence":"Endothelial-specific knockout/silencing in mouse retinal angiogenesis models, Gαi1/3 SUMOylation-site mutagenesis, VEGF signaling assays, and co-immunoprecipitation","pmids":["41390488"],"confidence":"High","gaps":["The SUMO E3 ligase mediating Gαi1/3 SUMOylation is not identified","How TrkB participates in a VEGF-driven complex is not mechanistically resolved"]},{"year":2026,"claim":"Generalized the RAB5IF-SUMO2-Gαi1/3 axis to BDNF/TrkB signaling in neurons, showing it drives Akt-mTOR activation and supports neuronal structure and resilience to depressive stimuli.","evidence":"Neuronal knockdown and conditional knockout, overexpression rescue, SUMOylation-site mutagenesis, co-IP, behavioral and dendritic/synaptic morphology assays in mouse hippocampus","pmids":["41915731"],"confidence":"High","gaps":["Whether mitochondrial dysfunction and impaired SUMO2 translation are independent or sequential contributors to the depressive phenotype is not separated","Direct molecular interactions of RAB5IF within mitochondria remain uncharacterized"]},{"year":2025,"claim":"Extended RAB5IF function to cancer, showing it promotes NSCLC proliferation and migration through the AKT-mTOR pathway while maintaining mitochondrial function.","evidence":"Lentiviral knockdown/overexpression in NSCLC cell lines with viability/proliferation/migration assays, AKT-mTOR Western blots, and nude mouse xenografts","pmids":["40318299"],"confidence":"Medium","gaps":["Whether the NSCLC effect proceeds through the same SUMO2-Gαi1/3 axis is not directly tested","Single-lab study with limited mechanistic depth beyond pathway-level Western blots"]},{"year":null,"claim":"How RAB5IF physically achieves selective control of SUMO2 mRNA translation and what its direct molecular interactions are within mitochondria remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No direct binding partners or RNA targets of RAB5IF are identified","No structural information on RAB5IF is available in the corpus"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0045182","term_label":"translation regulator activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[0,3,4]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,2,4]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,2]}],"complexes":[],"partners":[],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9BUV8","full_name":"GEL complex subunit OPTI","aliases":["Obligate partner of TMCO1 insertase","Rab5-interacting protein","RIP5","Respirasome Complex Assembly Factor 1"],"length_aa":137,"mass_kda":15.5,"function":"Component of the multi-pass translocon (MPT) complex that mediates insertion of multi-pass membrane proteins into the lipid bilayer of membranes (PubMed:36261522). The MPT complex takes over after the SEC61 complex: following membrane insertion of the first few transmembrane segments of proteins by the SEC61 complex, the MPT complex occludes the lateral gate of the SEC61 complex to promote insertion of subsequent transmembrane regions (PubMed:36261522). Within the MPT complex, the GEL subcomplex may mediate insertion of transmembrane regions into the membrane (PubMed:36261522). In addition to its role in multi-pass membrane insertion, RAB5IF/OPTI also acts as an assembly factor for mitochondrial respiratory complexes (PubMed:31536960)","subcellular_location":"Endoplasmic reticulum membrane; Mitochondrion inner membrane","url":"https://www.uniprot.org/uniprotkb/Q9BUV8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RAB5IF","classification":"Not Classified","n_dependent_lines":44,"n_total_lines":1208,"dependency_fraction":0.03642384105960265},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"TMCO1","stoichiometry":10.0},{"gene":"CCDC47","stoichiometry":4.0},{"gene":"BPNT1","stoichiometry":0.2},{"gene":"CANX","stoichiometry":0.2},{"gene":"MTMR2","stoichiometry":0.2},{"gene":"TMED10","stoichiometry":0.2},{"gene":"NCLN","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/RAB5IF","total_profiled":1310},"omim":[{"mim_id":"619960","title":"RAB5-INTERACTING FACTOR; RAB5IF","url":"https://www.omim.org/entry/619960"},{"mim_id":"616994","title":"CRANIOFACIAL DYSMORPHISM, SKELETAL ANOMALIES, AND IMPAIRED INTELLECTUAL DEVELOPMENT SYNDROME 2; CFSMR2","url":"https://www.omim.org/entry/616994"},{"mim_id":"612733","title":"THO COMPLEX, SUBUNIT 5; THOC5","url":"https://www.omim.org/entry/612733"},{"mim_id":"213980","title":"CRANIOFACIAL DYSMORPHISM, SKELETAL ANOMALIES, AND IMPAIRED INTELLECTUAL DEVELOPMENT SYNDROME 1; CFSMR1","url":"https://www.omim.org/entry/213980"},{"mim_id":"179512","title":"RAS-ASSOCIATED PROTEIN RAB5A; RAB5A","url":"https://www.omim.org/entry/179512"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Mitochondria","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":222.7}],"url":"https://www.proteinatlas.org/search/RAB5IF"},"hgnc":{"alias_symbol":["PNAS-11","RIP5","RCAF1","OPTI"],"prev_symbol":["C20orf24"]},"alphafold":{"accession":"Q9BUV8","domains":[{"cath_id":"-","chopping":"37-133","consensus_level":"high","plddt":76.7092,"start":37,"end":133}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BUV8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BUV8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BUV8-F1-predicted_aligned_error_v6.png","plddt_mean":72.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RAB5IF","jax_strain_url":"https://www.jax.org/strain/search?query=RAB5IF"},"sequence":{"accession":"Q9BUV8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BUV8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BUV8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BUV8"}},"corpus_meta":[{"pmid":"29115371","id":"PMC_29115371","title":"A novel method of neural differentiation of PC12 cells by using Opti-MEM as a basic induction medium.","date":"2017","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/29115371","citation_count":62,"is_preprint":false},{"pmid":"9407638","id":"PMC_9407638","title":"Clinical and laboratory experience with erythrocyte and platelet preparations from a 0.5CPD Erythro-Sol opti system.","date":"1997","source":"Vox sanguinis","url":"https://pubmed.ncbi.nlm.nih.gov/9407638","citation_count":36,"is_preprint":false},{"pmid":"2785595","id":"PMC_2785595","title":"Murine trophoblast can be killed by allospecific cytotoxic T lymphocytes generated in GIBCO Opti-MEM medium.","date":"1989","source":"Journal of reproductive immunology","url":"https://pubmed.ncbi.nlm.nih.gov/2785595","citation_count":27,"is_preprint":false},{"pmid":"31717443","id":"PMC_31717443","title":"The Pivotal Role of Long Noncoding RNA RAB5IF in the Proliferation of Hepatocellular Carcinoma Via LGR5 Mediated β-Catenin and c-Myc Signaling.","date":"2019","source":"Biomolecules","url":"https://pubmed.ncbi.nlm.nih.gov/31717443","citation_count":13,"is_preprint":false},{"pmid":"36924668","id":"PMC_36924668","title":"Optically activated MEK1/2 inhibitors (Opti-MEKi) as potential antimelanoma agents.","date":"2023","source":"European journal of medicinal chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/36924668","citation_count":5,"is_preprint":false},{"pmid":"1284683","id":"PMC_1284683","title":"Automated blood component preparation with the Opti system: three years' experience.","date":"1992","source":"Beitrage zur Infusionstherapie = Contributions to infusion therapy","url":"https://pubmed.ncbi.nlm.nih.gov/1284683","citation_count":5,"is_preprint":false},{"pmid":"36186786","id":"PMC_36186786","title":"Opti-4TB: A protocol for a prospective cohort study evaluating the performance of new biomarkers for active tuberculosis outcome prediction.","date":"2022","source":"Frontiers in medicine","url":"https://pubmed.ncbi.nlm.nih.gov/36186786","citation_count":3,"is_preprint":false},{"pmid":"40318299","id":"PMC_40318299","title":"Rab5if is a potential therapeutic target of NSCLC.","date":"2025","source":"Cancer genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40318299","citation_count":2,"is_preprint":false},{"pmid":"41390488","id":"PMC_41390488","title":"Endothelial RAB5IF is required for pathological and developmental retinal angiogenesis.","date":"2025","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/41390488","citation_count":1,"is_preprint":false},{"pmid":"39581731","id":"PMC_39581731","title":"OPTI-HEP-D: a protocol for an intervention study comprising screening and linkage to care of people living with hepatitis D in Catalonia.","date":"2024","source":"BMJ open","url":"https://pubmed.ncbi.nlm.nih.gov/39581731","citation_count":1,"is_preprint":false},{"pmid":"10863135","id":"PMC_10863135","title":"Two different concentrations of Opti-Plus(R) compared for daily protein cleaning of a disposable contact lens.","date":"2000","source":"International contact lens clinic (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/10863135","citation_count":1,"is_preprint":false},{"pmid":"41915731","id":"PMC_41915731","title":"The protein RAB5IF promotes BDNF signaling by stimulating the SUMOylation of Gαi1/3 to reduce depressive-like behaviors in mice.","date":"2026","source":"Science signaling","url":"https://pubmed.ncbi.nlm.nih.gov/41915731","citation_count":0,"is_preprint":false},{"pmid":"42156708","id":"PMC_42156708","title":"Real-World Outcomes of Opti-Hep-D: An Innovative, Multicentre and Multidisciplinary Program Improving Hepatitis D Cascade of Care.","date":"2026","source":"Liver international : official journal of the International Association for the Study of the Liver","url":"https://pubmed.ncbi.nlm.nih.gov/42156708","citation_count":0,"is_preprint":false},{"pmid":"32319870","id":"PMC_32319870","title":"The Case of the Cognitive (Opti)miser: Electrophysiological Correlates of Working Memory Maintenance Predict Demand Avoidance.","date":"2020","source":"Journal of cognitive neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/32319870","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.17.683537","title":"DMEM, or Opti-MEM, that is the Question: An Important Consideration for Extracellular Vesicle Isolation and their Downstream Applications","date":"2025-11-18","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.17.683537","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.08.16.25333839","title":"Overcoming Emmetropic Presbyopia by Optimal Keratoplasty (Opti-K)","date":"2025-08-21","source":"bioRxiv","url":"https://doi.org/10.1101/2025.08.16.25333839","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10491,"output_tokens":1513,"usd":0.027084,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8266,"output_tokens":2053,"usd":0.046328,"stage2_stop_reason":"end_turn"},"total_usd":0.073412,"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\": 2025,\n      \"finding\": \"RAB5IF silencing in retinal microvascular endothelial cells impeded mitochondrial respiration and ribosome biogenesis, specifically suppressing SUMO2 mRNA translation initiation and consequently lowering SUMO2 protein levels, defining RAB5IF as an upstream regulator of SUMO2 expression at the translational level.\",\n      \"method\": \"Proteomic sequencing, gene silencing (siRNA/shRNA), Western blot, mitochondrial respiration assay, in vivo retinal angiogenesis models (oxygen-induced retinopathy, laser-induced choroidal neovascularization in mice)\",\n      \"journal\": \"Nature Communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (proteomics, KD, in vivo models, functional assays) in a single rigorous study with clear mechanistic pathway delineation\",\n      \"pmids\": [\"41390488\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RAB5IF is required for physiological retinal vascular development and pathological retinal angiogenesis; endothelial-specific loss of RAB5IF suppressed VEGF signaling through reduction of SUMO2, which is required for SUMOylation of Gαi1/3 at Lys277, and Gαi1/3 SUMOylation is necessary for VEGF-induced signaling and pro-angiogenic activity.\",\n      \"method\": \"In vivo knockout/silencing in mouse retinal angiogenesis models, mutagenesis of Gαi1/3 SUMOylation sites, VEGF signaling assays, co-immunoprecipitation of TrkB-SUMO2-Gαi1/3 complexes\",\n      \"journal\": \"Nature Communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal functional validation with mutagenesis, in vivo models, and multiple orthogonal assays in one study\",\n      \"pmids\": [\"41390488\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In hippocampal neurons, RAB5IF promotes BDNF/TrkB signaling by maintaining translational efficiency of Sumo2 mRNA; RAB5IF silencing or knockout reduces SUMO2 protein, impairs SUMOylation of Gαi1/3 at Lys277, and disrupts formation of TrkB-SUMO2-Gαi1/3 signaling complexes required for downstream Akt-mTOR activation.\",\n      \"method\": \"Neuronal RAB5IF knockdown and conditional knockout in mouse hippocampus, overexpression rescue, site-directed mutagenesis of Gαi1/3 SUMOylation sites, co-immunoprecipitation, BDNF signaling assays, dendritic morphology and synaptic density quantification\",\n      \"journal\": \"Science Signaling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — mutagenesis, KO rescue, co-IP, multiple in vitro and in vivo orthogonal methods establishing mechanistic pathway\",\n      \"pmids\": [\"41915731\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"RAB5IF knockdown or conditional knockout in mouse hippocampus impairs mitochondrial function and dendritic branching/synaptic density in neurons, and induces depressive-like behaviors; conversely, RAB5IF overexpression in hippocampus mitigates depressive phenotype caused by chronic mild stress.\",\n      \"method\": \"Conditional knockout and AAV-mediated overexpression/knockdown in mouse hippocampus, behavioral assays (depressive-like behavior), mitochondrial function assays, dendritic morphology quantification in cultured hippocampal neurons\",\n      \"journal\": \"Science Signaling\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — gain- and loss-of-function in vivo with defined cellular and behavioral phenotypes, replicated across multiple approaches in one study\",\n      \"pmids\": [\"41915731\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RAB5IF knockdown in NSCLC cell lines inhibited cell viability, proliferation, and migration, and impaired mitochondrial function; overexpression promoted proliferation and migration; these effects were mediated through the AKT-mTOR pathway, confirmed both in vitro and in vivo in xenograft models.\",\n      \"method\": \"Lentiviral knockdown and overexpression in NSCLC cell lines, Western blot (AKT-mTOR pathway), cell viability/proliferation/migration assays, mitochondrial function assays, nude mouse xenograft models\",\n      \"journal\": \"Cancer Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal gain/loss-of-function with pathway validation, single lab, in vivo confirmation but limited mechanistic depth\",\n      \"pmids\": [\"40318299\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RAB5IF is a mitochondrial protein that promotes ribosome biogenesis and mitochondrial respiration to support translational efficiency of SUMO2 mRNA; elevated SUMO2 protein then SUMOylates Gαi1/3 at Lys277, enabling assembly of TrkB-SUMO2-Gαi1/3 signaling complexes that activate downstream Akt-mTOR signaling in response to VEGF and BDNF, thereby driving retinal angiogenesis and neuronal resilience against depressive stimuli, while also promoting NSCLC cell proliferation and migration via the AKT-mTOR pathway.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RAB5IF is a mitochondrial protein that couples mitochondrial respiration and ribosome biogenesis to a SUMO2-dependent signaling axis governing angiogenesis, neuronal resilience, and tumor cell growth [#0, #2]. Mechanistically, RAB5IF sustains the translational efficiency of SUMO2 mRNA, and loss of RAB5IF lowers SUMO2 protein levels by suppressing SUMO2 translation initiation [#0, #2]. The resulting SUMO2 is required for SUMOylation of G\\u03b1i1/3 at Lys277, which licenses assembly of TrkB-SUMO2-G\\u03b1i1/3 signaling complexes and downstream Akt-mTOR activation in response to VEGF and BDNF [#1, #2]. Through this axis, endothelial RAB5IF is required for physiological and pathological retinal angiogenesis [#1], hippocampal RAB5IF supports dendritic branching, synaptic density, and protection against depressive-like behavior [#2, #3], and in NSCLC cells RAB5IF promotes proliferation and migration via the AKT-mTOR pathway [#4]. Across these settings, RAB5IF function is consistently tied to maintenance of mitochondrial function [#0, #3, #4].\",\n  \"teleology\": [\n    {\n      \"year\": 2025,\n      \"claim\": \"Established that RAB5IF acts upstream of SUMO2 at the translational level by linking mitochondrial respiration and ribosome biogenesis to SUMO2 mRNA translation initiation, defining the entry point of its mechanism.\",\n      \"evidence\": \"Proteomic sequencing, gene silencing, Western blot, and mitochondrial respiration assays in retinal microvascular endothelial cells\",\n      \"pmids\": [\"41390488\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The molecular mechanism by which RAB5IF selectively controls SUMO2 mRNA translation initiation is not defined\",\n        \"Whether RAB5IF directly binds ribosomal components or SUMO2 mRNA is not shown\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Connected the RAB5IF-SUMO2 axis to VEGF signaling by showing SUMO2-dependent SUMOylation of G\\u03b1i1/3 at Lys277 and assembly of TrkB-SUMO2-G\\u03b1i1/3 complexes are required for pro-angiogenic activity.\",\n      \"evidence\": \"Endothelial-specific knockout/silencing in mouse retinal angiogenesis models, G\\u03b1i1/3 SUMOylation-site mutagenesis, VEGF signaling assays, and co-immunoprecipitation\",\n      \"pmids\": [\"41390488\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The SUMO E3 ligase mediating G\\u03b1i1/3 SUMOylation is not identified\",\n        \"How TrkB participates in a VEGF-driven complex is not mechanistically resolved\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Generalized the RAB5IF-SUMO2-G\\u03b1i1/3 axis to BDNF/TrkB signaling in neurons, showing it drives Akt-mTOR activation and supports neuronal structure and resilience to depressive stimuli.\",\n      \"evidence\": \"Neuronal knockdown and conditional knockout, overexpression rescue, SUMOylation-site mutagenesis, co-IP, behavioral and dendritic/synaptic morphology assays in mouse hippocampus\",\n      \"pmids\": [\"41915731\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether mitochondrial dysfunction and impaired SUMO2 translation are independent or sequential contributors to the depressive phenotype is not separated\",\n        \"Direct molecular interactions of RAB5IF within mitochondria remain uncharacterized\"\n      ]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Extended RAB5IF function to cancer, showing it promotes NSCLC proliferation and migration through the AKT-mTOR pathway while maintaining mitochondrial function.\",\n      \"evidence\": \"Lentiviral knockdown/overexpression in NSCLC cell lines with viability/proliferation/migration assays, AKT-mTOR Western blots, and nude mouse xenografts\",\n      \"pmids\": [\"40318299\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether the NSCLC effect proceeds through the same SUMO2-G\\u03b1i1/3 axis is not directly tested\",\n        \"Single-lab study with limited mechanistic depth beyond pathway-level Western blots\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RAB5IF physically achieves selective control of SUMO2 mRNA translation and what its direct molecular interactions are within mitochondria remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No direct binding partners or RNA targets of RAB5IF are identified\",\n        \"No structural information on RAB5IF is available in the corpus\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0045182\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [0, 3, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 2, 4]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":5,"faith_total":5,"faith_pct":100.0}}