{"gene":"GIMAP2","run_date":"2026-04-28T18:06:52","timeline":{"discoveries":[{"year":2010,"finding":"Crystal structures of GIMAP2 in nucleotide-free, GDP-bound, and GTP-bound states revealed that it adopts a TRAFAC-class guanine nucleotide-binding domain with a unique amphipathic helix α7. GDP-bound GIMAP2 is monomeric, while GTP binding induces oligomerization via two distinct interfaces: GTP-induced stabilization of switch I mediates dimerization across the nucleotide-binding site, and structural rearrangements in switch II release helix α7, enabling oligomerization through a second interface.","method":"X-ray crystallography of multiple nucleotide states, site-directed mutagenesis confirming the oligomer architecture","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 — crystal structures in multiple states combined with mutagenesis validation","pmids":["21059949"],"is_preprint":false},{"year":2010,"finding":"GIMAP2 oligomers localize to the surface of lipid droplets in Jurkat T cells, functioning as a GTP-dependent protein scaffold at intracellular membranes.","method":"Fluorescence imaging in Jurkat T cell line, structural and biochemical analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — direct localization experiment with functional scaffold role supported by structural data","pmids":["21059949"],"is_preprint":false},{"year":2013,"finding":"GIMAP7 stimulates GTP hydrolysis by GIMAP2 via heterodimerization, supplying a catalytic arginine from one monomer to the opposing monomer in a trans-acting mechanism; GIMAP2 alone has low intrinsic GTPase activity that is activated by GIMAP7.","method":"Crystal structure of GTP-bound GIMAP7 homodimer, GTPase activity assays, identification of catalytic arginine by mutagenesis","journal":"Structure (London, England : 1993)","confidence":"High","confidence_rationale":"Tier 1 — structural and biochemical reconstitution with mutagenesis identifying the catalytic mechanism","pmids":["23454188"],"is_preprint":false},{"year":2013,"finding":"GIMAP7 was identified as a lipid droplet-associated binding partner of GIMAP2, with both proteins found on lipid droplets and their expression differentially regulated in human T cell lymphoma lines.","method":"Screening of GIMAP family members on lipid droplets, co-localization studies","journal":"Structure (London, England : 1993)","confidence":"Medium","confidence_rationale":"Tier 2 — direct localization and interaction data, single study","pmids":["23454188"],"is_preprint":false},{"year":2020,"finding":"GIMAP2 localizes to the endoplasmic reticulum and on the surface of lipid droplets in MDA-MB-436 breast cancer cells, confirmed by co-localization of GIMAP2-mCherry fusion protein with ER and lipid droplet markers under super-resolution microscopy; endogenous GIMAP2 showed the same distribution.","method":"Super-resolution fluorescence microscopy (N-SIM) with organelle-specific chemical dyes, retroviral expression of GIMAP2-mCherry fusion protein, immunofluorescence of endogenous protein","journal":"Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences","confidence":"Medium","confidence_rationale":"Tier 2 — direct localization by live imaging and immunostaining, but functional consequence not fully established","pmids":["32306002"],"is_preprint":false},{"year":2021,"finding":"GIMAP2 knockdown in oral squamous cell carcinoma cells caused cell cycle arrest associated with downregulation of CDK4, CDK6, and phosphorylated Rb, and upregulation of p53 and p21, and shifted apoptotic balance by upregulating Bcl-2 and downregulating Bax and Bak.","method":"siRNA knockdown, immunoblotting for cell cycle and apoptosis regulators, cell growth assays","journal":"Oncology letters","confidence":"Medium","confidence_rationale":"Tier 3 — loss-of-function with defined molecular readouts but no upstream pathway placement","pmids":["34992682"],"is_preprint":false}],"current_model":"GIMAP2 is a TRAFAC-class GTPase that, upon GTP binding, oligomerizes via two G-domain interfaces and assembles as a nucleotide-regulated scaffold on lipid droplets and the endoplasmic reticulum; its low intrinsic GTPase activity is trans-activated by heterodimerization with GIMAP7, which supplies a catalytic arginine, linking nucleotide cycling to regulation of lymphocyte survival and apoptosis."},"narrative":{"teleology":[{"year":2010,"claim":"Determining how GIMAP2 senses nucleotide state established that GTP binding drives oligomerization through two distinct G-domain interfaces — a switch-I-mediated dimer interface and a switch-II-dependent helix-α7 interface — converting a monomeric GDP-bound protein into a higher-order scaffold.","evidence":"X-ray crystallography of nucleotide-free, GDP-bound, and GTP-bound GIMAP2 with site-directed mutagenesis in vitro","pmids":["21059949"],"confidence":"High","gaps":["No effectors or cargo proteins that recognize the oligomeric scaffold have been identified","Physiological signals controlling GIMAP2 nucleotide loading are unknown","Oligomer stoichiometry in vivo has not been defined"]},{"year":2010,"claim":"The oligomeric scaffold was shown to localize to lipid droplet surfaces in T cells, establishing GIMAP2 as a GTP-dependent membrane-associated platform rather than a cytosolic signaling GTPase.","evidence":"Fluorescence imaging of GIMAP2 constructs in Jurkat T cells","pmids":["21059949"],"confidence":"High","gaps":["Mechanism of membrane anchoring (lipid interaction vs. protein receptor) is unresolved","Functional consequence of lipid droplet association for T cell biology was not tested"]},{"year":2013,"claim":"The puzzle of GIMAP2's very low intrinsic GTPase activity was resolved by demonstrating that GIMAP7 heterodimerization trans-activates hydrolysis, with GIMAP7 supplying a catalytic arginine to the GIMAP2 active site, thereby linking nucleotide cycling to inter-GIMAP partnering.","evidence":"Crystal structure of GTP-bound GIMAP7 homodimer, GTPase assays, and mutagenesis of catalytic arginine","pmids":["23454188"],"confidence":"High","gaps":["Whether other GIMAP family members also trans-activate GIMAP2 is unknown","Downstream consequences of GTP hydrolysis for scaffold disassembly have not been visualized in cells"]},{"year":2013,"claim":"GIMAP7 was identified as a lipid droplet-resident binding partner of GIMAP2, and their expression was found to be differentially regulated in T cell lymphoma lines, suggesting coordinated regulation of the heterodimer on lipid droplets.","evidence":"Co-localization studies and expression profiling across human T cell lymphoma lines","pmids":["23454188"],"confidence":"Medium","gaps":["No reciprocal co-immunoprecipitation or endogenous interaction validation was performed","Functional significance of differential expression in lymphoma remains unexplored"]},{"year":2020,"claim":"GIMAP2 localization was extended beyond lipid droplets to include the endoplasmic reticulum, indicating dual compartment residence that may reflect a lipid droplet biogenesis or ER-lipid droplet contact site role.","evidence":"Super-resolution N-SIM microscopy with organelle-specific dyes and immunofluorescence of endogenous GIMAP2 in MDA-MB-436 cells","pmids":["32306002"],"confidence":"Medium","gaps":["Whether ER and lipid droplet pools represent distinct functional states is unknown","No perturbation experiment linked ER localization to a specific function"]},{"year":2021,"claim":"Loss-of-function experiments established that GIMAP2 promotes cell cycle progression and modulates apoptotic balance, connecting the GTPase scaffold to CDK4/CDK6–Rb signaling and Bcl-2 family regulation.","evidence":"siRNA knockdown in oral squamous cell carcinoma cells with immunoblotting for cell cycle and apoptosis regulators","pmids":["34992682"],"confidence":"Medium","gaps":["No upstream pathway placement — whether effects are direct or indirect is unresolved","Findings are from a single cancer cell type and have not been extended to lymphocytes","Relationship between GTPase activity/lipid droplet scaffolding and cell cycle control is unknown"]},{"year":null,"claim":"How GIMAP2's GTP-dependent oligomeric scaffold on lipid droplets and the ER mechanistically connects to downstream control of cell survival and proliferation remains the central open question.","evidence":"","pmids":[],"confidence":"Low","gaps":["No direct substrates, effectors, or cargo have been identified for the GIMAP2 scaffold","The physiological GEF or nucleotide exchange mechanism is unknown","In vivo genetic models (knockout mice or human genetic studies) have not been reported for GIMAP2 specifically"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003924","term_label":"GTPase activity","supporting_discovery_ids":[0,2]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005811","term_label":"lipid droplet","supporting_discovery_ids":[1,3,4]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[4]}],"pathway":[],"complexes":[],"partners":["GIMAP7"],"other_free_text":[]},"mechanistic_narrative":"GIMAP2 is a TRAFAC-class GTPase that functions as a nucleotide-regulated scaffold on intracellular membranes, linking lipid droplet and endoplasmic reticulum biology to lymphocyte survival. In the GDP-bound state GIMAP2 is monomeric, but GTP binding stabilizes switch I to drive dimerization across the nucleotide-binding site and releases amphipathic helix α7 to enable higher-order oligomerization, forming scaffolds on the surface of lipid droplets [PMID:21059949]. GIMAP2 possesses low intrinsic GTPase activity; heterodimerization with GIMAP7 trans-activates hydrolysis through a catalytic arginine supplied in trans, coupling the nucleotide cycle to partner-dependent regulation [PMID:23454188]. Knockdown of GIMAP2 in cancer cells induces cell cycle arrest via downregulation of CDK4/CDK6 and altered apoptotic balance through changes in Bcl-2 family members [PMID:34992682]."},"prefetch_data":{"uniprot":{"accession":"Q9UG22","full_name":"GTPase IMAP family member 2","aliases":["Immunity-associated protein 2","hIMAP2"],"length_aa":337,"mass_kda":38.0,"function":"The heterodimer formed by GIMAP2 and GIMAP7 has GTPase activity. In contrast, GIMAP2 has no GTPase activity by itself","subcellular_location":"Lipid droplet","url":"https://www.uniprot.org/uniprotkb/Q9UG22/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GIMAP2","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/GIMAP2","total_profiled":1310},"omim":[{"mim_id":"616961","title":"GTPase, IMAP FAMILY, MEMBER 7; GIMAP7","url":"https://www.omim.org/entry/616961"},{"mim_id":"616960","title":"GTPase, IMAP FAMILY, MEMBER 6; GIMAP6","url":"https://www.omim.org/entry/616960"},{"mim_id":"608087","title":"GTPase, IMAP FAMILY, MEMBER 4; GIMAP4","url":"https://www.omim.org/entry/608087"},{"mim_id":"608085","title":"GTPase, IMAP FAMILY, MEMBER 2; GIMAP2","url":"https://www.omim.org/entry/608085"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Lipid droplets","reliability":"Supported"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"lymphoid tissue","ntpm":73.4}],"url":"https://www.proteinatlas.org/search/GIMAP2"},"hgnc":{"alias_symbol":["DKFZp586D0824","HIMAP2","IMAP2","IAN12"],"prev_symbol":[]},"alphafold":{"accession":"Q9UG22","domains":[{"cath_id":"3.40.50.300","chopping":"22-228","consensus_level":"high","plddt":94.209,"start":22,"end":228},{"cath_id":"1.20.5","chopping":"229-330","consensus_level":"medium","plddt":89.7102,"start":229,"end":330}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UG22","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UG22-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UG22-F1-predicted_aligned_error_v6.png","plddt_mean":88.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GIMAP2","jax_strain_url":"https://www.jax.org/strain/search?query=GIMAP2"},"sequence":{"accession":"Q9UG22","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UG22.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UG22/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UG22"}},"corpus_meta":[{"pmid":"23041938","id":"PMC_23041938","title":"Genome-wide association study identifies GIMAP as a novel susceptibility locus for Behcet's disease.","date":"2012","source":"Annals of the rheumatic diseases","url":"https://pubmed.ncbi.nlm.nih.gov/23041938","citation_count":93,"is_preprint":false},{"pmid":"21059949","id":"PMC_21059949","title":"Structural basis of oligomerization in septin-like GTPase of immunity-associated protein 2 (GIMAP2).","date":"2010","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/21059949","citation_count":51,"is_preprint":false},{"pmid":"23454188","id":"PMC_23454188","title":"Structural insights into the mechanism of GTPase activation in the GIMAP family.","date":"2013","source":"Structure (London, England : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/23454188","citation_count":39,"is_preprint":false},{"pmid":"21686278","id":"PMC_21686278","title":"GTP-dependent scaffold formation in the GTPase of Immunity Associated Protein family.","date":"2011","source":"Small GTPases","url":"https://pubmed.ncbi.nlm.nih.gov/21686278","citation_count":11,"is_preprint":false},{"pmid":"20516611","id":"PMC_20516611","title":"Purification, crystallization and preliminary X-ray analysis of human GIMAP2.","date":"2010","source":"Acta crystallographica. Section F, Structural biology and crystallization communications","url":"https://pubmed.ncbi.nlm.nih.gov/20516611","citation_count":5,"is_preprint":false},{"pmid":"34992682","id":"PMC_34992682","title":"Aberrant GIMAP2 expression affects oral squamous cell carcinoma progression by promoting cell cycle and inhibiting apoptosis.","date":"2021","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/34992682","citation_count":5,"is_preprint":false},{"pmid":"32306002","id":"PMC_32306002","title":"[Subcellular localization of GTPase of immunity-associated protein 2].","date":"2020","source":"Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences","url":"https://pubmed.ncbi.nlm.nih.gov/32306002","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":4894,"output_tokens":1389,"usd":0.017758},"stage2":{"model":"claude-opus-4-6","input_tokens":4630,"output_tokens":1778,"usd":0.1014},"total_usd":0.119158,"stage1_batch_id":"msgbatch_01DzrsgVgYngY1hvM3DU1yF2","stage2_batch_id":"msgbatch_01KA9b7iRzKFdhoBUT7vCvSe","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"Crystal structures of GIMAP2 in nucleotide-free, GDP-bound, and GTP-bound states revealed that it adopts a TRAFAC-class guanine nucleotide-binding domain with a unique amphipathic helix α7. GDP-bound GIMAP2 is monomeric, while GTP binding induces oligomerization via two distinct interfaces: GTP-induced stabilization of switch I mediates dimerization across the nucleotide-binding site, and structural rearrangements in switch II release helix α7, enabling oligomerization through a second interface.\",\n      \"method\": \"X-ray crystallography of multiple nucleotide states, site-directed mutagenesis confirming the oligomer architecture\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures in multiple states combined with mutagenesis validation\",\n      \"pmids\": [\"21059949\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"GIMAP2 oligomers localize to the surface of lipid droplets in Jurkat T cells, functioning as a GTP-dependent protein scaffold at intracellular membranes.\",\n      \"method\": \"Fluorescence imaging in Jurkat T cell line, structural and biochemical analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct localization experiment with functional scaffold role supported by structural data\",\n      \"pmids\": [\"21059949\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GIMAP7 stimulates GTP hydrolysis by GIMAP2 via heterodimerization, supplying a catalytic arginine from one monomer to the opposing monomer in a trans-acting mechanism; GIMAP2 alone has low intrinsic GTPase activity that is activated by GIMAP7.\",\n      \"method\": \"Crystal structure of GTP-bound GIMAP7 homodimer, GTPase activity assays, identification of catalytic arginine by mutagenesis\",\n      \"journal\": \"Structure (London, England : 1993)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — structural and biochemical reconstitution with mutagenesis identifying the catalytic mechanism\",\n      \"pmids\": [\"23454188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GIMAP7 was identified as a lipid droplet-associated binding partner of GIMAP2, with both proteins found on lipid droplets and their expression differentially regulated in human T cell lymphoma lines.\",\n      \"method\": \"Screening of GIMAP family members on lipid droplets, co-localization studies\",\n      \"journal\": \"Structure (London, England : 1993)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct localization and interaction data, single study\",\n      \"pmids\": [\"23454188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"GIMAP2 localizes to the endoplasmic reticulum and on the surface of lipid droplets in MDA-MB-436 breast cancer cells, confirmed by co-localization of GIMAP2-mCherry fusion protein with ER and lipid droplet markers under super-resolution microscopy; endogenous GIMAP2 showed the same distribution.\",\n      \"method\": \"Super-resolution fluorescence microscopy (N-SIM) with organelle-specific chemical dyes, retroviral expression of GIMAP2-mCherry fusion protein, immunofluorescence of endogenous protein\",\n      \"journal\": \"Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct localization by live imaging and immunostaining, but functional consequence not fully established\",\n      \"pmids\": [\"32306002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"GIMAP2 knockdown in oral squamous cell carcinoma cells caused cell cycle arrest associated with downregulation of CDK4, CDK6, and phosphorylated Rb, and upregulation of p53 and p21, and shifted apoptotic balance by upregulating Bcl-2 and downregulating Bax and Bak.\",\n      \"method\": \"siRNA knockdown, immunoblotting for cell cycle and apoptosis regulators, cell growth assays\",\n      \"journal\": \"Oncology letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — loss-of-function with defined molecular readouts but no upstream pathway placement\",\n      \"pmids\": [\"34992682\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GIMAP2 is a TRAFAC-class GTPase that, upon GTP binding, oligomerizes via two G-domain interfaces and assembles as a nucleotide-regulated scaffold on lipid droplets and the endoplasmic reticulum; its low intrinsic GTPase activity is trans-activated by heterodimerization with GIMAP7, which supplies a catalytic arginine, linking nucleotide cycling to regulation of lymphocyte survival and apoptosis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"GIMAP2 is a TRAFAC-class GTPase that functions as a nucleotide-regulated scaffold on intracellular membranes, linking lipid droplet and endoplasmic reticulum biology to lymphocyte survival. In the GDP-bound state GIMAP2 is monomeric, but GTP binding stabilizes switch I to drive dimerization across the nucleotide-binding site and releases amphipathic helix α7 to enable higher-order oligomerization, forming scaffolds on the surface of lipid droplets [PMID:21059949]. GIMAP2 possesses low intrinsic GTPase activity; heterodimerization with GIMAP7 trans-activates hydrolysis through a catalytic arginine supplied in trans, coupling the nucleotide cycle to partner-dependent regulation [PMID:23454188]. Knockdown of GIMAP2 in cancer cells induces cell cycle arrest via downregulation of CDK4/CDK6 and altered apoptotic balance through changes in Bcl-2 family members [PMID:34992682].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Determining how GIMAP2 senses nucleotide state established that GTP binding drives oligomerization through two distinct G-domain interfaces — a switch-I-mediated dimer interface and a switch-II-dependent helix-α7 interface — converting a monomeric GDP-bound protein into a higher-order scaffold.\",\n      \"evidence\": \"X-ray crystallography of nucleotide-free, GDP-bound, and GTP-bound GIMAP2 with site-directed mutagenesis in vitro\",\n      \"pmids\": [\"21059949\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No effectors or cargo proteins that recognize the oligomeric scaffold have been identified\",\n        \"Physiological signals controlling GIMAP2 nucleotide loading are unknown\",\n        \"Oligomer stoichiometry in vivo has not been defined\"\n      ]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"The oligomeric scaffold was shown to localize to lipid droplet surfaces in T cells, establishing GIMAP2 as a GTP-dependent membrane-associated platform rather than a cytosolic signaling GTPase.\",\n      \"evidence\": \"Fluorescence imaging of GIMAP2 constructs in Jurkat T cells\",\n      \"pmids\": [\"21059949\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Mechanism of membrane anchoring (lipid interaction vs. protein receptor) is unresolved\",\n        \"Functional consequence of lipid droplet association for T cell biology was not tested\"\n      ]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"The puzzle of GIMAP2's very low intrinsic GTPase activity was resolved by demonstrating that GIMAP7 heterodimerization trans-activates hydrolysis, with GIMAP7 supplying a catalytic arginine to the GIMAP2 active site, thereby linking nucleotide cycling to inter-GIMAP partnering.\",\n      \"evidence\": \"Crystal structure of GTP-bound GIMAP7 homodimer, GTPase assays, and mutagenesis of catalytic arginine\",\n      \"pmids\": [\"23454188\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether other GIMAP family members also trans-activate GIMAP2 is unknown\",\n        \"Downstream consequences of GTP hydrolysis for scaffold disassembly have not been visualized in cells\"\n      ]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"GIMAP7 was identified as a lipid droplet-resident binding partner of GIMAP2, and their expression was found to be differentially regulated in T cell lymphoma lines, suggesting coordinated regulation of the heterodimer on lipid droplets.\",\n      \"evidence\": \"Co-localization studies and expression profiling across human T cell lymphoma lines\",\n      \"pmids\": [\"23454188\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No reciprocal co-immunoprecipitation or endogenous interaction validation was performed\",\n        \"Functional significance of differential expression in lymphoma remains unexplored\"\n      ]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"GIMAP2 localization was extended beyond lipid droplets to include the endoplasmic reticulum, indicating dual compartment residence that may reflect a lipid droplet biogenesis or ER-lipid droplet contact site role.\",\n      \"evidence\": \"Super-resolution N-SIM microscopy with organelle-specific dyes and immunofluorescence of endogenous GIMAP2 in MDA-MB-436 cells\",\n      \"pmids\": [\"32306002\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether ER and lipid droplet pools represent distinct functional states is unknown\",\n        \"No perturbation experiment linked ER localization to a specific function\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Loss-of-function experiments established that GIMAP2 promotes cell cycle progression and modulates apoptotic balance, connecting the GTPase scaffold to CDK4/CDK6–Rb signaling and Bcl-2 family regulation.\",\n      \"evidence\": \"siRNA knockdown in oral squamous cell carcinoma cells with immunoblotting for cell cycle and apoptosis regulators\",\n      \"pmids\": [\"34992682\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No upstream pathway placement — whether effects are direct or indirect is unresolved\",\n        \"Findings are from a single cancer cell type and have not been extended to lymphocytes\",\n        \"Relationship between GTPase activity/lipid droplet scaffolding and cell cycle control is unknown\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How GIMAP2's GTP-dependent oligomeric scaffold on lipid droplets and the ER mechanistically connects to downstream control of cell survival and proliferation remains the central open question.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No direct substrates, effectors, or cargo have been identified for the GIMAP2 scaffold\",\n        \"The physiological GEF or nucleotide exchange mechanism is unknown\",\n        \"In vivo genetic models (knockout mice or human genetic studies) have not been reported for GIMAP2 specifically\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003924\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005811\", \"supporting_discovery_ids\": [1, 3, 4]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [],\n    \"complexes\": [],\n    \"partners\": [\"GIMAP7\"],\n    \"other_free_text\": []\n  }\n}\n```"}