{"gene":"BNIP2","run_date":"2026-04-28T17:12:38","timeline":{"discoveries":[{"year":1999,"finding":"BNIP-2 is a substrate of FGF receptor-1 (FGFR1) tyrosine kinase; FGFR1 phosphorylates BNIP-2 on tyrosine residues both in cells and in vitro, and tyrosine phosphorylation of BNIP-2 prevents its binding to Cdc42GAP and abolishes its GAP-like activity toward Cdc42.","method":"Yeast two-hybrid screen, co-immunoprecipitation 'capture' experiments with kinase-dead FGFR1, in vitro kinase assay with recombinant BNIP-2 and active FGFR1, GST pulldown, GTPase activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro kinase assay with recombinant proteins plus multiple orthogonal binding/functional assays in one study","pmids":["10551883"],"is_preprint":false},{"year":2000,"finding":"The C-terminal BCH (BNIP-2 and Cdc42GAP Homology) domain of BNIP-2 binds Cdc42 and stimulates its GTPase activity via a novel arginine-patch motif (Arg-235 and Arg-238); site-directed mutagenesis of these arginines abolishes GAP activity without affecting Cdc42 binding, and a sequence 288EYV290 on BNIP-2 plus the Switch I and Rho Insert region on Cdc42 mediate binding.","method":"GST pulldown, GTPase activity assay, site-directed mutagenesis, deletion studies","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution with mutagenesis defining catalytic residues","pmids":["10799524"],"is_preprint":false},{"year":2000,"finding":"The BCH domain of BNIP-2 mediates homophilic (BNIP-2:BNIP-2) and heterophilic (BNIP-2:Cdc42GAP) protein-protein interactions; the region 217RRKMP221 is the major BCH–BCH interaction site, distinct from the arginine-patch required for GAP activity and the Cdc42-binding sequence 288EYV290.","method":"GST pulldown, co-immunoprecipitation, yeast two-hybrid, deletion mutagenesis, molecular modeling","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods with mutagenesis to map interaction surfaces","pmids":["10954711"],"is_preprint":false},{"year":2001,"finding":"The BCH domain of BNIP-Salpha (a BNIP-2 homolog) is a novel apoptosis-inducing sequence; expression of the full BCH domain induces apoptosis, and deletion of the homophilic interaction motif within the BCH domain abrogates this pro-apoptotic effect.","method":"Overexpression in cells, deletion mutagenesis, apoptosis assays, co-immunoprecipitation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function mutagenesis with clear phenotypic readout, single study","pmids":["11741952"],"is_preprint":false},{"year":2003,"finding":"BPGAP1, a novel RhoGAP containing a BCH domain, forms homophilic and heterophilic complexes with other BCH-domain proteins including BNIP-2 via their BCH domains, as shown by pulldown and co-immunoprecipitation; BPGAP1 selectively stimulates RhoA GTPase activity in vivo and induces pseudopodia and cell migration in MCF7 cells.","method":"GST pulldown, co-immunoprecipitation, fluorescence microscopy, cell migration assay, dominant-negative GTPase coexpression","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods in a single study; finding pertains to BCH-domain interaction of BNIP-2 with BPGAP1","pmids":["12944407"],"is_preprint":false},{"year":2005,"finding":"BNIP-2 induces cell elongation and membrane protrusions via its BCH domain by binding Cdc42 through a unique motif 285VPMEYVGI292; cells expressing BNIP-2 mutants lacking this motif fail to produce morphological changes, and the effect is blocked by dominant-negative Cdc42.","method":"Transient overexpression, deletion/mutagenesis, GST pulldown, dominant-negative GTPase coexpression, fluorescence microscopy","journal":"Experimental cell research","confidence":"High","confidence_rationale":"Tier 1-2 — mutagenesis defining critical binding motif combined with multiple functional assays","pmids":["15652341"],"is_preprint":false},{"year":2006,"finding":"BNIP-Salpha induces cell rounding and apoptosis by binding RhoA via BCH domain residues 133-177 (overlapping a RhoA switch I homology region and a REM class I RhoA-binding motif), displacing p50RhoGAP/Cdc42GAP from RhoA and thereby restoring RhoA activation; dominant-negative RhoA prevents cell rounding and apoptosis.","method":"Overexpression and mutagenesis, co-immunoprecipitation, dominant-negative GTPase coexpression, cell morphology and apoptosis assays","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods with mutagenesis defining functional residues in single study","pmids":["16331259"],"is_preprint":false},{"year":2006,"finding":"Brain-specific BNIP-H/Caytaxin (a BNIP-2 family member) directly binds kidney-type glutaminase (KGA), relocalizes KGA from mitochondria to neurite terminals, and reduces steady-state glutamate levels by inhibiting KGA enzyme activity.","method":"Protein precipitation, MALDI-MS, co-immunoprecipitation with endogenous proteins, GST pulldown, immunohistochemistry, glutamate measurement in PC12 cells","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods including endogenous co-IP, in-cell enzyme activity measurement, localization by imaging","pmids":["16899818"],"is_preprint":false},{"year":2007,"finding":"BNIP-2 and BNIP-XL are cleaved by caspases during apoptosis; the caspase cleavage sites on BNIP-2 are located within its N-terminal EF-hand motif, releasing BCH-domain-containing fragments proposed to contribute to pro-apoptotic activity.","method":"In vitro caspase cleavage assay, cell-based apoptosis assays, site mapping by deletion/mutagenesis","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — in vitro cleavage assay combined with cell-based validation, single study","pmids":["17961507"],"is_preprint":false},{"year":2008,"finding":"During myoblast differentiation, BNIP-2 interacts with the cell surface receptor Cdo and the scaffold protein JLP (which also binds p38α/β MAPK), linking Cdo to Cdc42 activation; gain- and loss-of-function experiments show that the Cdo–BNIP-2 interaction stimulates Cdc42 activity, which in turn promotes p38α/β activity and myogenic differentiation.","method":"Co-immunoprecipitation, gain- and loss-of-function (siRNA knockdown, overexpression), p38 activity assay, Cdc42 pull-down activity assay, myogenic differentiation assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP plus gain/loss-of-function with defined signaling and phenotypic readouts, replicated pathway","pmids":["18678706"],"is_preprint":false},{"year":2008,"finding":"BNIPXL (BNIP2 Extra Long), the full contig of BMCC1, uses its BCH domain to interact with specific conformers of RhoA (fast-cycling F30L and dominant-negative T19N, but not constitutively active mutants) and with the catalytic DH-PH domains of the RhoGEF Lbc; overexpression of BNIPXL reduces active RhoA levels and inhibits Lbc-induced oncogenic transformation, while knockdown has the reverse effect.","method":"Co-immunoprecipitation, GST pulldown, RhoA activity assay, transformation assay, siRNA knockdown","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — reciprocal binding assays with conformer selectivity, gain/loss-of-function with functional readout, single study with multiple orthogonal methods","pmids":["18445682"],"is_preprint":false},{"year":2010,"finding":"BNIP-2 is cleaved by granzyme B at site IEAD28 during NK cell-mediated killing of tumor cells; cleavage is caspase-independent, occurs on endogenous BNIP-2, and both full-length and the granzyme B-cleaved truncated form of BNIP-2 are pro-apoptotic and trigger subsequent caspase-dependent cleavage of BNIP-2 at a distinct site.","method":"In vitro granzyme B cleavage assay with recombinant BNIP-2, NK cell cytotoxicity assay with endogenous BNIP-2, site mutagenesis, siRNA knockdown, apoptosis assays","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro reconstitution with endogenous validation and site mutagenesis","pmids":["20704564"],"is_preprint":false},{"year":2010,"finding":"The BCH domain of p50RhoGAP/Cdc42GAP sequesters RhoA from inactivation by the adjacent GAP domain in cis; the BCH domain binds RhoA regardless of nucleotide state (GDP or GTP), and a RhoA-binding motif (residues 85-120) plus an intramolecular interaction motif (residues 169-197) within the BCH domain are both required for full suppression of GAP activity; deletion of the BCH domain enhances GAP activity and causes cell rounding prevented by active RhoA.","method":"BCH domain deletion mutants, site-directed mutagenesis, cell morphology assays, dominant-active RhoA rescue, co-immunoprecipitation, subcellular localization studies","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 — multiple mutants with functional readouts and rescue experiments in a single thorough study","pmids":["20660160"],"is_preprint":false},{"year":2014,"finding":"KIF5B (kinesin-1 heavy chain) directly interacts with BNIP-2 via BNIP-2's BCH domain (binding both motor and tail domains of KIF5B); KIF5B mediates anterograde endosomal transport of BNIP-2 along microtubules, and KIF5B knockdown causes aberrant BNIP-2 aggregation and impairs p38MAPK activation and myogenic differentiation.","method":"Co-immunoprecipitation, far-Western blot, live-cell microscopy with organelle markers, dominant-negative KIF5B, siRNA knockdown, p38 activity assay, myogenic differentiation assays","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1-2 — direct binding confirmed by far-Western, transport visualized by live imaging, loss-of-function with defined signaling and differentiation readouts","pmids":["25378581"],"is_preprint":false},{"year":2014,"finding":"The CRAL-TRIO/BCH domain of BNIP-2 specifically binds phosphatidylserine; this lipid interaction is required for vesicular localization of BNIP-2 (to Golgi, early and recycling endosomes, mitochondria) and for its ability to induce cell elongation and processes. BNIP-2 also interacts with kinesin light chains (KLCs) via a conserved WED motif in its N-terminal region, and KLC interaction plus kinesin-1 transport are required for BNIP-2-induced cell morphological changes.","method":"Lipid-binding assay, co-immunoprecipitation with KLC, subcellular fractionation, organelle marker colocalization, live imaging for transport speed, mutagenesis of WED motif and CRAL-TRIO domain","journal":"Genes to cells","confidence":"High","confidence_rationale":"Tier 1-2 — direct lipid binding assay with mutagenesis, KLC co-IP, live imaging, and functional morphology assays in one study","pmids":["25472445"],"is_preprint":false},{"year":2014,"finding":"Granzyme B cleaves BNIP-2 at the IEAD28 tetrapeptide motif; extended substrate context beyond P4-P1 (particularly P1' and P3' positions) determines differential cleavage efficiency between mouse and human granzyme B, with murine granzyme B cleaving BNIP-2 more efficiently than human granzyme B despite identical IEAD tetrapeptide.","method":"In vitro kinetic degradome analysis, site-directed mutagenesis of primed-site residues, comparative cleavage assays","journal":"BMC biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 — in vitro kinetic assays with mutagenesis; single study","pmids":["25208769"],"is_preprint":false},{"year":2020,"finding":"BNIP-2 scaffolds GEF-H1 and RhoA on microtubules via binding to both; upon microtubule disassembly, BNIP-2–GEF-H1 interaction increases and BNIP-2 facilitates GEF-H1-driven RhoA activation. Depletion of BNIP-2 in MDA-MB-231 breast cancer cells decreases RhoA activity, uncouples RhoA–GEF-H1 interaction, and promotes cell migration. BNIP-2 also traffics with kinesin-1 on microtubules.","method":"siRNA knockdown, co-immunoprecipitation, RhoA activity assay, nocodazole-induced microtubule disassembly, live-cell migration assay, proximity ligation assay","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (reciprocal co-IP, GTPase activity, migration assay, PLA) with mechanistic rescue experiments","pmids":["32789168"],"is_preprint":false},{"year":2022,"finding":"BNIP-2 promotes cardiomyoblast differentiation by scaffolding LATS1 to phosphorylate and inactivate YAP (increasing cytosolic YAP retention), and this requires BNIP-2-mediated activation of cellular contractility (RhoA/Myosin II). Turbo-ID proximity labeling, super-resolution imaging, and biochemical pulldown together demonstrate the BNIP-2–LATS1 scaffolding interaction.","method":"Turbo-ID proximity labeling, super-resolution microscopy, biochemical pulldown, siRNA knockdown/overexpression, YAP phosphorylation assay, cardiomyoblast differentiation assay (cTnT, Myl2 expression)","journal":"Advanced science","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods including proximity proteomics, super-resolution, biochemical pulldown, and functional differentiation assays","pmids":["35975420"],"is_preprint":false}],"current_model":"BNIP-2 is a BCH-domain scaffold protein that integrates Rho GTPase signaling with diverse cellular processes: its BCH domain directly binds and activates Cdc42 (via an arginine-patch GAP mechanism), sequesters or presents RhoA to its regulators (GEFs such as GEF-H1 and Lbc, and GAPs such as p50RhoGAP), is phosphorylated on tyrosine by FGFR1 (abolishing its Cdc42 GAP activity and Cdc42GAP binding), is cleaved by granzyme B and caspases during apoptosis, traffics on microtubule-based vesicles via kinesin-1 (KIF5B) using a phosphatidylserine-binding CRAL-TRIO domain and a KLC-binding WED motif, and acts as a signaling hub that couples receptor signaling (Cdo), microtubule dynamics (GEF-H1/RhoA), and mechanotransduction (LATS1/YAP) to regulate myoblast and cardiomyoblast differentiation, cell migration, and apoptosis."},"narrative":{"teleology":[{"year":1999,"claim":"Establishing that BNIP-2 is a signaling target of receptor tyrosine kinases resolved its upstream regulation: FGFR1 phosphorylates BNIP-2 on tyrosine, and this phosphorylation switches off BNIP-2's GAP-like activity toward Cdc42 and prevents its binding to Cdc42GAP.","evidence":"Yeast two-hybrid, co-IP with kinase-dead FGFR1, in vitro kinase assay with recombinant proteins, GTPase activity assay","pmids":["10551883"],"confidence":"High","gaps":["Specific tyrosine phosphorylation sites on BNIP-2 not mapped","Physiological context of FGFR1–BNIP-2 signaling in tissue not established"]},{"year":2000,"claim":"Defining the BCH domain as a novel GTPase-regulatory and protein-interaction module established the core molecular mechanism of BNIP-2: the BCH domain binds Cdc42 via a 285VPMEYVGI292 motif, stimulates GTPase activity through an arginine-patch (R235/R238), and mediates homophilic and heterophilic BCH–BCH interactions through a distinct 217RRKMP221 site.","evidence":"GST pulldown, GTPase activity assay, site-directed mutagenesis, yeast two-hybrid, molecular modeling","pmids":["10799524","10954711"],"confidence":"High","gaps":["No crystal structure of the BCH domain–Cdc42 complex","Whether BCH homodimerization regulates GAP activity in cells not tested"]},{"year":2005,"claim":"Demonstrating that BNIP-2 drives Cdc42-dependent cell elongation and membrane protrusions linked its biochemical activities to cell morphogenesis, establishing the BCH domain's Cdc42-binding motif as essential for morphological output.","evidence":"Overexpression with deletion/mutagenesis, dominant-negative Cdc42 blockade, fluorescence microscopy in cultured cells","pmids":["15652341"],"confidence":"High","gaps":["Downstream effectors of Cdc42 mediating protrusion not identified","Endogenous loss-of-function not performed"]},{"year":2006,"claim":"Work on the BNIP-2 homolog BNIP-Sα revealed that BCH domains can also bind and activate RhoA by displacing p50RhoGAP, establishing that the BCH domain family modulates multiple Rho GTPases through sequestration of GAPs.","evidence":"Overexpression/mutagenesis, co-IP, dominant-negative RhoA rescue, cell rounding and apoptosis assays","pmids":["16331259"],"confidence":"High","gaps":["Whether BNIP-2 itself uses the same RhoA-sequestration mechanism in the same cell types not directly shown"]},{"year":2007,"claim":"Identification of caspase cleavage within BNIP-2's N-terminal EF-hand motif connected BNIP-2 to apoptotic signaling, suggesting that proteolytic release of BCH-domain fragments contributes to pro-apoptotic activity.","evidence":"In vitro caspase cleavage assay, cell-based apoptosis assays, site mapping by deletion/mutagenesis","pmids":["17961507"],"confidence":"Medium","gaps":["Pro-apoptotic activity of the cleaved fragment not reconstituted in isolation","Physiological relevance of caspase cleavage of BNIP-2 not validated in vivo"]},{"year":2008,"claim":"Placing BNIP-2 in the Cdo receptor signaling complex resolved how extracellular cues activate Cdc42–p38 MAPK to drive myogenic differentiation, establishing BNIP-2 as a differentiation scaffold bridging a cell-surface receptor to an intracellular GTPase.","evidence":"Reciprocal co-IP, siRNA knockdown and overexpression, Cdc42 and p38 activity assays, myogenic differentiation assays in C2C12 myoblasts","pmids":["18678706"],"confidence":"High","gaps":["Structural basis of Cdo–BNIP-2 interaction unknown","In vivo muscle phenotype of BNIP-2 loss not assessed"]},{"year":2008,"claim":"Discovery that the BNIP-2 family member BNIPXL binds specific RhoA conformers and inhibits Lbc-driven oncogenic transformation generalized BCH-domain function to include sequestration of RhoA from RhoGEFs.","evidence":"Co-IP, GST pulldown with RhoA mutants, RhoA activity assay, transformation assay, siRNA knockdown","pmids":["18445682"],"confidence":"High","gaps":["Whether BNIP-2 itself similarly engages Lbc not tested at this stage"]},{"year":2010,"claim":"Identification of granzyme B cleavage at IEAD28 revealed a caspase-independent route by which BNIP-2 is activated during immune-mediated killing, with both full-length and truncated BNIP-2 promoting apoptosis that then feeds into caspase-dependent cleavage.","evidence":"In vitro granzyme B cleavage with recombinant BNIP-2, NK cell cytotoxicity assay with endogenous BNIP-2, site mutagenesis, siRNA, apoptosis assays","pmids":["20704564"],"confidence":"High","gaps":["How granzyme B-cleaved BNIP-2 mechanistically induces apoptosis not resolved","In vivo relevance in tumor immune surveillance not demonstrated"]},{"year":2014,"claim":"Revealing that BNIP-2 is transported by kinesin-1 (KIF5B heavy chain and KLCs) on microtubule-bound vesicles, and that this transport depends on phosphatidylserine binding by its CRAL-TRIO domain and a WED motif for KLC binding, established BNIP-2 as an actively transported signaling scaffold whose vesicular trafficking is essential for p38 MAPK activation and myogenic differentiation.","evidence":"Far-Western blot, co-IP with KIF5B/KLC, lipid-binding assay, live-cell imaging of vesicular transport, organelle marker colocalization, WED/CRAL-TRIO mutagenesis, siRNA knockdown, differentiation assays","pmids":["25378581","25472445"],"confidence":"High","gaps":["Cargo identity of BNIP-2-containing vesicles beyond BNIP-2 itself not defined","Whether phosphatidylserine binding is regulated by signaling not tested"]},{"year":2020,"claim":"Demonstrating that BNIP-2 scaffolds GEF-H1 and RhoA on microtubules and that microtubule disassembly enhances BNIP-2–GEF-H1 interaction to activate RhoA resolved how BNIP-2 couples microtubule dynamics to Rho signaling, with functional consequences for cell migration.","evidence":"siRNA knockdown, co-IP, RhoA activity assay, nocodazole-induced microtubule disassembly, proximity ligation assay, live-cell migration assay in MDA-MB-231 cells","pmids":["32789168"],"confidence":"High","gaps":["Structural basis of the tripartite BNIP-2–GEF-H1–RhoA complex not resolved","Whether BNIP-2 regulation of migration is relevant in vivo not assessed"]},{"year":2022,"claim":"Showing that BNIP-2 scaffolds LATS1 to phosphorylate and inactivate YAP, coupling RhoA/Myosin II-driven contractility to Hippo pathway output, established BNIP-2 as a mechanotransduction hub that promotes cardiomyoblast differentiation.","evidence":"Turbo-ID proximity labeling, super-resolution microscopy, biochemical pulldown, siRNA/overexpression, YAP phosphorylation assay, cardiomyoblast differentiation markers (cTnT, Myl2)","pmids":["35975420"],"confidence":"High","gaps":["Whether BNIP-2 directly binds LATS1 or acts through an intermediary not fully resolved","In vivo cardiac phenotype of BNIP-2 loss not reported"]},{"year":null,"claim":"Major open questions include the structural basis of BCH domain interactions with diverse partners, whether BNIP-2 loss produces developmental phenotypes in vivo, the identity and regulation of BNIP-2-containing vesicle cargo, and how FGFR1 phosphorylation integrates with the Cdo, GEF-H1, and LATS1 scaffolding functions of BNIP-2.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of BCH domain with any binding partner","No in vivo knockout phenotype reported","Integration of FGFR1 phosphorylation with scaffolding functions unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,6,10,12,16,17]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[9,13,16,17]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[14]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[14,16]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[13,14]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[14]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[5,16]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,9,16,17]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[9,17]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[8,11]}],"complexes":[],"partners":["CDC42","RHOA","KIF5B","FGFR1","ARHGAP1","ARHGEF2","CDO1","LATS1"],"other_free_text":[]},"mechanistic_narrative":"BNIP-2 is a BCH-domain scaffold protein that coordinates Rho GTPase signaling with cell differentiation, morphogenesis, migration, and apoptosis. Its C-terminal BCH domain directly binds Cdc42 and stimulates its GTPase activity via an arginine-patch motif, while also engaging RhoA and presenting it to regulators such as GEF-H1 and p50RhoGAP to control RhoA activation states [PMID:10799524, PMID:32789168, PMID:20660160]. BNIP-2 traffics on microtubule-based vesicles through phosphatidylserine binding by its CRAL-TRIO domain and kinesin-1 (KIF5B/KLC) interaction via a WED motif, coupling its signaling scaffold function to intracellular transport required for myoblast differentiation (via Cdo–Cdc42–p38 MAPK) and cardiomyoblast differentiation (via LATS1–YAP) [PMID:25378581, PMID:25472445, PMID:18678706, PMID:35975420]. BNIP-2 is a substrate of FGFR1 tyrosine kinase, which phosphorylates it to abolish its Cdc42 GAP activity, and is proteolytically cleaved by granzyme B and caspases during apoptosis, generating pro-apoptotic BCH-domain fragments [PMID:10551883, PMID:20704564, PMID:17961507]."},"prefetch_data":{"uniprot":{"accession":"Q12982","full_name":"BCL2/adenovirus E1B 19 kDa protein-interacting protein 2","aliases":[],"length_aa":314,"mass_kda":36.0,"function":"Implicated in the suppression of cell death. Interacts with the BCL-2 and adenovirus E1B 19 kDa proteins","subcellular_location":"Cytoplasm; Cytoplasm, perinuclear region","url":"https://www.uniprot.org/uniprotkb/Q12982/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/BNIP2","classification":"Not Classified","n_dependent_lines":65,"n_total_lines":383,"dependency_fraction":0.16971279373368145},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/BNIP2","total_profiled":1310},"omim":[{"mim_id":"611275","title":"BCL2/ADENOVIRUS E1B 19-KD PROTEIN-INTERACTING PROTEIN 2-LIKE; BNIPL","url":"https://www.omim.org/entry/611275"},{"mim_id":"610691","title":"PRUNE HOMOLOG 2 WITH BCH DOMAIN; PRUNE2","url":"https://www.omim.org/entry/610691"},{"mim_id":"609405","title":"RHO GTPase-ACTIVATING PROTEIN 8; ARHGAP8","url":"https://www.omim.org/entry/609405"},{"mim_id":"608179","title":"CAYTAXIN; ATCAY","url":"https://www.omim.org/entry/608179"},{"mim_id":"603292","title":"BCL2/ADENOVIRUS E1B 19-KD PROTEIN-INTERACTING PROTEIN 2; BNIP2","url":"https://www.omim.org/entry/603292"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"},{"location":"Nucleoli","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"bone marrow","ntpm":122.0}],"url":"https://www.proteinatlas.org/search/BNIP2"},"hgnc":{"alias_symbol":["Nip2","BNIP-2"],"prev_symbol":[]},"alphafold":{"accession":"Q12982","domains":[{"cath_id":"3.40.525.10","chopping":"119-307","consensus_level":"medium","plddt":88.4671,"start":119,"end":307}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q12982","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q12982-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q12982-F1-predicted_aligned_error_v6.png","plddt_mean":72.31},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=BNIP2","jax_strain_url":"https://www.jax.org/strain/search?query=BNIP2"},"sequence":{"accession":"Q12982","fasta_url":"https://rest.uniprot.org/uniprotkb/Q12982.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q12982/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q12982"}},"corpus_meta":[{"pmid":"17584741","id":"PMC_17584741","title":"Arabidopsis NIP2;1, a major intrinsic protein transporter of lactic acid induced by anoxic stress.","date":"2007","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17584741","citation_count":116,"is_preprint":false},{"pmid":"18678706","id":"PMC_18678706","title":"A Cdo-Bnip-2-Cdc42 signaling pathway regulates p38alpha/beta MAPK activity and myogenic differentiation.","date":"2008","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/18678706","citation_count":91,"is_preprint":false},{"pmid":"21242194","id":"PMC_21242194","title":"miR-20a targets BNIP2 and contributes chemotherapeutic resistance in colorectal adenocarcinoma SW480 and SW620 cell lines.","date":"2011","source":"Acta biochimica et biophysica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/21242194","citation_count":87,"is_preprint":false},{"pmid":"17535851","id":"PMC_17535851","title":"Characterization of NIP2/centrobin, a novel substrate of Nek2, and its potential role in microtubule stabilization.","date":"2007","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/17535851","citation_count":74,"is_preprint":false},{"pmid":"28323408","id":"PMC_28323408","title":"Monodispersed Carbon-Coated Cubic NiP2 Nanoparticles Anchored on Carbon Nanotubes as Ultra-Long-Life Anodes for Reversible Lithium Storage.","date":"2017","source":"ACS nano","url":"https://pubmed.ncbi.nlm.nih.gov/28323408","citation_count":58,"is_preprint":false},{"pmid":"16899818","id":"PMC_16899818","title":"Brain-specific BNIP-2-homology protein Caytaxin relocalises glutaminase to neurite terminals and reduces glutamate levels.","date":"2006","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/16899818","citation_count":54,"is_preprint":false},{"pmid":"33309839","id":"PMC_33309839","title":"Astrocyte-derived exosomes carry microRNA-17-5p to protect neonatal rats from hypoxic-ischemic brain damage via inhibiting BNIP-2 expression.","date":"2020","source":"Neurotoxicology","url":"https://pubmed.ncbi.nlm.nih.gov/33309839","citation_count":53,"is_preprint":false},{"pmid":"16954136","id":"PMC_16954136","title":"Aquaporin NIP2;1 is mainly localized to the ER membrane and shows root-specific accumulation in Arabidopsis thaliana.","date":"2006","source":"Plant & cell physiology","url":"https://pubmed.ncbi.nlm.nih.gov/16954136","citation_count":45,"is_preprint":false},{"pmid":"12944407","id":"PMC_12944407","title":"Concerted regulation of cell dynamics by BNIP-2 and Cdc42GAP homology/Sec14p-like, proline-rich, and GTPase-activating protein domains of a novel Rho GTPase-activating protein, BPGAP1.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12944407","citation_count":44,"is_preprint":false},{"pmid":"10551883","id":"PMC_10551883","title":"Tyrosine phosphorylation of the Bcl-2-associated protein BNIP-2 by fibroblast growth factor receptor-1 prevents its binding to Cdc42GAP and Cdc42.","date":"1999","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10551883","citation_count":42,"is_preprint":false},{"pmid":"10954711","id":"PMC_10954711","title":"The BNIP-2 and Cdc42GAP homology domain of BNIP-2 mediates its homophilic association and heterophilic interaction with Cdc42GAP.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10954711","citation_count":39,"is_preprint":false},{"pmid":"18445682","id":"PMC_18445682","title":"BNIP2 extra long inhibits RhoA and cellular transformation by Lbc RhoGEF via its BCH domain.","date":"2008","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/18445682","citation_count":38,"is_preprint":false},{"pmid":"11741952","id":"PMC_11741952","title":"The BNIP-2 and Cdc42GAP homology/Sec14p-like domain of BNIP-Salpha is a novel apoptosis-inducing sequence.","date":"2001","source":"The Journal of biological 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cell","url":"https://pubmed.ncbi.nlm.nih.gov/20660160","citation_count":24,"is_preprint":false},{"pmid":"20511645","id":"PMC_20511645","title":"Centrobin/NIP2 is a microtubule stabilizer whose activity is enhanced by PLK1 phosphorylation during mitosis.","date":"2010","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/20511645","citation_count":24,"is_preprint":false},{"pmid":"12901880","id":"PMC_12901880","title":"BNIPL-2, a novel homologue of BNIP-2, interacts with Bcl-2 and Cdc42GAP in apoptosis.","date":"2003","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/12901880","citation_count":23,"is_preprint":false},{"pmid":"22710163","id":"PMC_22710163","title":"Functional plasticity of the BNIP-2 and Cdc42GAP Homology (BCH) domain in cell signaling and cell dynamics.","date":"2012","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/22710163","citation_count":22,"is_preprint":false},{"pmid":"22479462","id":"PMC_22479462","title":"Cross-species analyses identify the BNIP-2 and Cdc42GAP homology (BCH) domain as a distinct functional subclass of the CRAL_TRIO/Sec14 superfamily.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22479462","citation_count":20,"is_preprint":false},{"pmid":"19117032","id":"PMC_19117032","title":"Nip2/centrobin may be a substrate of Nek2 that is required for proper spindle assembly during mitosis in early mouse embryos.","date":"2009","source":"Molecular reproduction and development","url":"https://pubmed.ncbi.nlm.nih.gov/19117032","citation_count":20,"is_preprint":false},{"pmid":"32584998","id":"PMC_32584998","title":"The grapevine NIP2;1 aquaporin is a silicon channel.","date":"2020","source":"Journal of experimental 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vitro kinase assay with recombinant BNIP-2 and active FGFR1, GST pulldown, GTPase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro kinase assay with recombinant proteins plus multiple orthogonal binding/functional assays in one study\",\n      \"pmids\": [\"10551883\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The C-terminal BCH (BNIP-2 and Cdc42GAP Homology) domain of BNIP-2 binds Cdc42 and stimulates its GTPase activity via a novel arginine-patch motif (Arg-235 and Arg-238); site-directed mutagenesis of these arginines abolishes GAP activity without affecting Cdc42 binding, and a sequence 288EYV290 on BNIP-2 plus the Switch I and Rho Insert region on Cdc42 mediate binding.\",\n      \"method\": \"GST pulldown, GTPase activity assay, site-directed mutagenesis, deletion studies\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution with mutagenesis defining catalytic residues\",\n      \"pmids\": [\"10799524\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The BCH domain of BNIP-2 mediates homophilic (BNIP-2:BNIP-2) and heterophilic (BNIP-2:Cdc42GAP) protein-protein interactions; the region 217RRKMP221 is the major BCH–BCH interaction site, distinct from the arginine-patch required for GAP activity and the Cdc42-binding sequence 288EYV290.\",\n      \"method\": \"GST pulldown, co-immunoprecipitation, yeast two-hybrid, deletion mutagenesis, molecular modeling\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods with mutagenesis to map interaction surfaces\",\n      \"pmids\": [\"10954711\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The BCH domain of BNIP-Salpha (a BNIP-2 homolog) is a novel apoptosis-inducing sequence; expression of the full BCH domain induces apoptosis, and deletion of the homophilic interaction motif within the BCH domain abrogates this pro-apoptotic effect.\",\n      \"method\": \"Overexpression in cells, deletion mutagenesis, apoptosis assays, co-immunoprecipitation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function mutagenesis with clear phenotypic readout, single study\",\n      \"pmids\": [\"11741952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"BPGAP1, a novel RhoGAP containing a BCH domain, forms homophilic and heterophilic complexes with other BCH-domain proteins including BNIP-2 via their BCH domains, as shown by pulldown and co-immunoprecipitation; BPGAP1 selectively stimulates RhoA GTPase activity in vivo and induces pseudopodia and cell migration in MCF7 cells.\",\n      \"method\": \"GST pulldown, co-immunoprecipitation, fluorescence microscopy, cell migration assay, dominant-negative GTPase coexpression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods in a single study; finding pertains to BCH-domain interaction of BNIP-2 with BPGAP1\",\n      \"pmids\": [\"12944407\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"BNIP-2 induces cell elongation and membrane protrusions via its BCH domain by binding Cdc42 through a unique motif 285VPMEYVGI292; cells expressing BNIP-2 mutants lacking this motif fail to produce morphological changes, and the effect is blocked by dominant-negative Cdc42.\",\n      \"method\": \"Transient overexpression, deletion/mutagenesis, GST pulldown, dominant-negative GTPase coexpression, fluorescence microscopy\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — mutagenesis defining critical binding motif combined with multiple functional assays\",\n      \"pmids\": [\"15652341\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"BNIP-Salpha induces cell rounding and apoptosis by binding RhoA via BCH domain residues 133-177 (overlapping a RhoA switch I homology region and a REM class I RhoA-binding motif), displacing p50RhoGAP/Cdc42GAP from RhoA and thereby restoring RhoA activation; dominant-negative RhoA prevents cell rounding and apoptosis.\",\n      \"method\": \"Overexpression and mutagenesis, co-immunoprecipitation, dominant-negative GTPase coexpression, cell morphology and apoptosis assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods with mutagenesis defining functional residues in single study\",\n      \"pmids\": [\"16331259\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Brain-specific BNIP-H/Caytaxin (a BNIP-2 family member) directly binds kidney-type glutaminase (KGA), relocalizes KGA from mitochondria to neurite terminals, and reduces steady-state glutamate levels by inhibiting KGA enzyme activity.\",\n      \"method\": \"Protein precipitation, MALDI-MS, co-immunoprecipitation with endogenous proteins, GST pulldown, immunohistochemistry, glutamate measurement in PC12 cells\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods including endogenous co-IP, in-cell enzyme activity measurement, localization by imaging\",\n      \"pmids\": [\"16899818\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"BNIP-2 and BNIP-XL are cleaved by caspases during apoptosis; the caspase cleavage sites on BNIP-2 are located within its N-terminal EF-hand motif, releasing BCH-domain-containing fragments proposed to contribute to pro-apoptotic activity.\",\n      \"method\": \"In vitro caspase cleavage assay, cell-based apoptosis assays, site mapping by deletion/mutagenesis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vitro cleavage assay combined with cell-based validation, single study\",\n      \"pmids\": [\"17961507\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"During myoblast differentiation, BNIP-2 interacts with the cell surface receptor Cdo and the scaffold protein JLP (which also binds p38α/β MAPK), linking Cdo to Cdc42 activation; gain- and loss-of-function experiments show that the Cdo–BNIP-2 interaction stimulates Cdc42 activity, which in turn promotes p38α/β activity and myogenic differentiation.\",\n      \"method\": \"Co-immunoprecipitation, gain- and loss-of-function (siRNA knockdown, overexpression), p38 activity assay, Cdc42 pull-down activity assay, myogenic differentiation assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP plus gain/loss-of-function with defined signaling and phenotypic readouts, replicated pathway\",\n      \"pmids\": [\"18678706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"BNIPXL (BNIP2 Extra Long), the full contig of BMCC1, uses its BCH domain to interact with specific conformers of RhoA (fast-cycling F30L and dominant-negative T19N, but not constitutively active mutants) and with the catalytic DH-PH domains of the RhoGEF Lbc; overexpression of BNIPXL reduces active RhoA levels and inhibits Lbc-induced oncogenic transformation, while knockdown has the reverse effect.\",\n      \"method\": \"Co-immunoprecipitation, GST pulldown, RhoA activity assay, transformation assay, siRNA knockdown\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal binding assays with conformer selectivity, gain/loss-of-function with functional readout, single study with multiple orthogonal methods\",\n      \"pmids\": [\"18445682\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"BNIP-2 is cleaved by granzyme B at site IEAD28 during NK cell-mediated killing of tumor cells; cleavage is caspase-independent, occurs on endogenous BNIP-2, and both full-length and the granzyme B-cleaved truncated form of BNIP-2 are pro-apoptotic and trigger subsequent caspase-dependent cleavage of BNIP-2 at a distinct site.\",\n      \"method\": \"In vitro granzyme B cleavage assay with recombinant BNIP-2, NK cell cytotoxicity assay with endogenous BNIP-2, site mutagenesis, siRNA knockdown, apoptosis assays\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro reconstitution with endogenous validation and site mutagenesis\",\n      \"pmids\": [\"20704564\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The BCH domain of p50RhoGAP/Cdc42GAP sequesters RhoA from inactivation by the adjacent GAP domain in cis; the BCH domain binds RhoA regardless of nucleotide state (GDP or GTP), and a RhoA-binding motif (residues 85-120) plus an intramolecular interaction motif (residues 169-197) within the BCH domain are both required for full suppression of GAP activity; deletion of the BCH domain enhances GAP activity and causes cell rounding prevented by active RhoA.\",\n      \"method\": \"BCH domain deletion mutants, site-directed mutagenesis, cell morphology assays, dominant-active RhoA rescue, co-immunoprecipitation, subcellular localization studies\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple mutants with functional readouts and rescue experiments in a single thorough study\",\n      \"pmids\": [\"20660160\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"KIF5B (kinesin-1 heavy chain) directly interacts with BNIP-2 via BNIP-2's BCH domain (binding both motor and tail domains of KIF5B); KIF5B mediates anterograde endosomal transport of BNIP-2 along microtubules, and KIF5B knockdown causes aberrant BNIP-2 aggregation and impairs p38MAPK activation and myogenic differentiation.\",\n      \"method\": \"Co-immunoprecipitation, far-Western blot, live-cell microscopy with organelle markers, dominant-negative KIF5B, siRNA knockdown, p38 activity assay, myogenic differentiation assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct binding confirmed by far-Western, transport visualized by live imaging, loss-of-function with defined signaling and differentiation readouts\",\n      \"pmids\": [\"25378581\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The CRAL-TRIO/BCH domain of BNIP-2 specifically binds phosphatidylserine; this lipid interaction is required for vesicular localization of BNIP-2 (to Golgi, early and recycling endosomes, mitochondria) and for its ability to induce cell elongation and processes. BNIP-2 also interacts with kinesin light chains (KLCs) via a conserved WED motif in its N-terminal region, and KLC interaction plus kinesin-1 transport are required for BNIP-2-induced cell morphological changes.\",\n      \"method\": \"Lipid-binding assay, co-immunoprecipitation with KLC, subcellular fractionation, organelle marker colocalization, live imaging for transport speed, mutagenesis of WED motif and CRAL-TRIO domain\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct lipid binding assay with mutagenesis, KLC co-IP, live imaging, and functional morphology assays in one study\",\n      \"pmids\": [\"25472445\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Granzyme B cleaves BNIP-2 at the IEAD28 tetrapeptide motif; extended substrate context beyond P4-P1 (particularly P1' and P3' positions) determines differential cleavage efficiency between mouse and human granzyme B, with murine granzyme B cleaving BNIP-2 more efficiently than human granzyme B despite identical IEAD tetrapeptide.\",\n      \"method\": \"In vitro kinetic degradome analysis, site-directed mutagenesis of primed-site residues, comparative cleavage assays\",\n      \"journal\": \"BMC biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — in vitro kinetic assays with mutagenesis; single study\",\n      \"pmids\": [\"25208769\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"BNIP-2 scaffolds GEF-H1 and RhoA on microtubules via binding to both; upon microtubule disassembly, BNIP-2–GEF-H1 interaction increases and BNIP-2 facilitates GEF-H1-driven RhoA activation. Depletion of BNIP-2 in MDA-MB-231 breast cancer cells decreases RhoA activity, uncouples RhoA–GEF-H1 interaction, and promotes cell migration. BNIP-2 also traffics with kinesin-1 on microtubules.\",\n      \"method\": \"siRNA knockdown, co-immunoprecipitation, RhoA activity assay, nocodazole-induced microtubule disassembly, live-cell migration assay, proximity ligation assay\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (reciprocal co-IP, GTPase activity, migration assay, PLA) with mechanistic rescue experiments\",\n      \"pmids\": [\"32789168\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"BNIP-2 promotes cardiomyoblast differentiation by scaffolding LATS1 to phosphorylate and inactivate YAP (increasing cytosolic YAP retention), and this requires BNIP-2-mediated activation of cellular contractility (RhoA/Myosin II). Turbo-ID proximity labeling, super-resolution imaging, and biochemical pulldown together demonstrate the BNIP-2–LATS1 scaffolding interaction.\",\n      \"method\": \"Turbo-ID proximity labeling, super-resolution microscopy, biochemical pulldown, siRNA knockdown/overexpression, YAP phosphorylation assay, cardiomyoblast differentiation assay (cTnT, Myl2 expression)\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including proximity proteomics, super-resolution, biochemical pulldown, and functional differentiation assays\",\n      \"pmids\": [\"35975420\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"BNIP-2 is a BCH-domain scaffold protein that integrates Rho GTPase signaling with diverse cellular processes: its BCH domain directly binds and activates Cdc42 (via an arginine-patch GAP mechanism), sequesters or presents RhoA to its regulators (GEFs such as GEF-H1 and Lbc, and GAPs such as p50RhoGAP), is phosphorylated on tyrosine by FGFR1 (abolishing its Cdc42 GAP activity and Cdc42GAP binding), is cleaved by granzyme B and caspases during apoptosis, traffics on microtubule-based vesicles via kinesin-1 (KIF5B) using a phosphatidylserine-binding CRAL-TRIO domain and a KLC-binding WED motif, and acts as a signaling hub that couples receptor signaling (Cdo), microtubule dynamics (GEF-H1/RhoA), and mechanotransduction (LATS1/YAP) to regulate myoblast and cardiomyoblast differentiation, cell migration, and apoptosis.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"BNIP-2 is a BCH-domain scaffold protein that coordinates Rho GTPase signaling with cell differentiation, morphogenesis, migration, and apoptosis. Its C-terminal BCH domain directly binds Cdc42 and stimulates its GTPase activity via an arginine-patch motif, while also engaging RhoA and presenting it to regulators such as GEF-H1 and p50RhoGAP to control RhoA activation states [PMID:10799524, PMID:32789168, PMID:20660160]. BNIP-2 traffics on microtubule-based vesicles through phosphatidylserine binding by its CRAL-TRIO domain and kinesin-1 (KIF5B/KLC) interaction via a WED motif, coupling its signaling scaffold function to intracellular transport required for myoblast differentiation (via Cdo–Cdc42–p38 MAPK) and cardiomyoblast differentiation (via LATS1–YAP) [PMID:25378581, PMID:25472445, PMID:18678706, PMID:35975420]. BNIP-2 is a substrate of FGFR1 tyrosine kinase, which phosphorylates it to abolish its Cdc42 GAP activity, and is proteolytically cleaved by granzyme B and caspases during apoptosis, generating pro-apoptotic BCH-domain fragments [PMID:10551883, PMID:20704564, PMID:17961507].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Establishing that BNIP-2 is a signaling target of receptor tyrosine kinases resolved its upstream regulation: FGFR1 phosphorylates BNIP-2 on tyrosine, and this phosphorylation switches off BNIP-2's GAP-like activity toward Cdc42 and prevents its binding to Cdc42GAP.\",\n      \"evidence\": \"Yeast two-hybrid, co-IP with kinase-dead FGFR1, in vitro kinase assay with recombinant proteins, GTPase activity assay\",\n      \"pmids\": [\"10551883\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific tyrosine phosphorylation sites on BNIP-2 not mapped\", \"Physiological context of FGFR1–BNIP-2 signaling in tissue not established\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Defining the BCH domain as a novel GTPase-regulatory and protein-interaction module established the core molecular mechanism of BNIP-2: the BCH domain binds Cdc42 via a 285VPMEYVGI292 motif, stimulates GTPase activity through an arginine-patch (R235/R238), and mediates homophilic and heterophilic BCH–BCH interactions through a distinct 217RRKMP221 site.\",\n      \"evidence\": \"GST pulldown, GTPase activity assay, site-directed mutagenesis, yeast two-hybrid, molecular modeling\",\n      \"pmids\": [\"10799524\", \"10954711\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal structure of the BCH domain–Cdc42 complex\", \"Whether BCH homodimerization regulates GAP activity in cells not tested\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Demonstrating that BNIP-2 drives Cdc42-dependent cell elongation and membrane protrusions linked its biochemical activities to cell morphogenesis, establishing the BCH domain's Cdc42-binding motif as essential for morphological output.\",\n      \"evidence\": \"Overexpression with deletion/mutagenesis, dominant-negative Cdc42 blockade, fluorescence microscopy in cultured cells\",\n      \"pmids\": [\"15652341\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effectors of Cdc42 mediating protrusion not identified\", \"Endogenous loss-of-function not performed\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Work on the BNIP-2 homolog BNIP-Sα revealed that BCH domains can also bind and activate RhoA by displacing p50RhoGAP, establishing that the BCH domain family modulates multiple Rho GTPases through sequestration of GAPs.\",\n      \"evidence\": \"Overexpression/mutagenesis, co-IP, dominant-negative RhoA rescue, cell rounding and apoptosis assays\",\n      \"pmids\": [\"16331259\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether BNIP-2 itself uses the same RhoA-sequestration mechanism in the same cell types not directly shown\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identification of caspase cleavage within BNIP-2's N-terminal EF-hand motif connected BNIP-2 to apoptotic signaling, suggesting that proteolytic release of BCH-domain fragments contributes to pro-apoptotic activity.\",\n      \"evidence\": \"In vitro caspase cleavage assay, cell-based apoptosis assays, site mapping by deletion/mutagenesis\",\n      \"pmids\": [\"17961507\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Pro-apoptotic activity of the cleaved fragment not reconstituted in isolation\", \"Physiological relevance of caspase cleavage of BNIP-2 not validated in vivo\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Placing BNIP-2 in the Cdo receptor signaling complex resolved how extracellular cues activate Cdc42–p38 MAPK to drive myogenic differentiation, establishing BNIP-2 as a differentiation scaffold bridging a cell-surface receptor to an intracellular GTPase.\",\n      \"evidence\": \"Reciprocal co-IP, siRNA knockdown and overexpression, Cdc42 and p38 activity assays, myogenic differentiation assays in C2C12 myoblasts\",\n      \"pmids\": [\"18678706\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of Cdo–BNIP-2 interaction unknown\", \"In vivo muscle phenotype of BNIP-2 loss not assessed\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Discovery that the BNIP-2 family member BNIPXL binds specific RhoA conformers and inhibits Lbc-driven oncogenic transformation generalized BCH-domain function to include sequestration of RhoA from RhoGEFs.\",\n      \"evidence\": \"Co-IP, GST pulldown with RhoA mutants, RhoA activity assay, transformation assay, siRNA knockdown\",\n      \"pmids\": [\"18445682\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether BNIP-2 itself similarly engages Lbc not tested at this stage\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Identification of granzyme B cleavage at IEAD28 revealed a caspase-independent route by which BNIP-2 is activated during immune-mediated killing, with both full-length and truncated BNIP-2 promoting apoptosis that then feeds into caspase-dependent cleavage.\",\n      \"evidence\": \"In vitro granzyme B cleavage with recombinant BNIP-2, NK cell cytotoxicity assay with endogenous BNIP-2, site mutagenesis, siRNA, apoptosis assays\",\n      \"pmids\": [\"20704564\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How granzyme B-cleaved BNIP-2 mechanistically induces apoptosis not resolved\", \"In vivo relevance in tumor immune surveillance not demonstrated\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Revealing that BNIP-2 is transported by kinesin-1 (KIF5B heavy chain and KLCs) on microtubule-bound vesicles, and that this transport depends on phosphatidylserine binding by its CRAL-TRIO domain and a WED motif for KLC binding, established BNIP-2 as an actively transported signaling scaffold whose vesicular trafficking is essential for p38 MAPK activation and myogenic differentiation.\",\n      \"evidence\": \"Far-Western blot, co-IP with KIF5B/KLC, lipid-binding assay, live-cell imaging of vesicular transport, organelle marker colocalization, WED/CRAL-TRIO mutagenesis, siRNA knockdown, differentiation assays\",\n      \"pmids\": [\"25378581\", \"25472445\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cargo identity of BNIP-2-containing vesicles beyond BNIP-2 itself not defined\", \"Whether phosphatidylserine binding is regulated by signaling not tested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Demonstrating that BNIP-2 scaffolds GEF-H1 and RhoA on microtubules and that microtubule disassembly enhances BNIP-2–GEF-H1 interaction to activate RhoA resolved how BNIP-2 couples microtubule dynamics to Rho signaling, with functional consequences for cell migration.\",\n      \"evidence\": \"siRNA knockdown, co-IP, RhoA activity assay, nocodazole-induced microtubule disassembly, proximity ligation assay, live-cell migration assay in MDA-MB-231 cells\",\n      \"pmids\": [\"32789168\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the tripartite BNIP-2–GEF-H1–RhoA complex not resolved\", \"Whether BNIP-2 regulation of migration is relevant in vivo not assessed\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Showing that BNIP-2 scaffolds LATS1 to phosphorylate and inactivate YAP, coupling RhoA/Myosin II-driven contractility to Hippo pathway output, established BNIP-2 as a mechanotransduction hub that promotes cardiomyoblast differentiation.\",\n      \"evidence\": \"Turbo-ID proximity labeling, super-resolution microscopy, biochemical pulldown, siRNA/overexpression, YAP phosphorylation assay, cardiomyoblast differentiation markers (cTnT, Myl2)\",\n      \"pmids\": [\"35975420\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether BNIP-2 directly binds LATS1 or acts through an intermediary not fully resolved\", \"In vivo cardiac phenotype of BNIP-2 loss not reported\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Major open questions include the structural basis of BCH domain interactions with diverse partners, whether BNIP-2 loss produces developmental phenotypes in vivo, the identity and regulation of BNIP-2-containing vesicle cargo, and how FGFR1 phosphorylation integrates with the Cdo, GEF-H1, and LATS1 scaffolding functions of BNIP-2.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of BCH domain with any binding partner\", \"No in vivo knockout phenotype reported\", \"Integration of FGFR1 phosphorylation with scaffolding functions unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 6, 10, 12, 16, 17]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [9, 13, 16, 17]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [14, 16]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [13, 14]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [14]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [5, 16]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 9, 16, 17]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [9, 17]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [8, 11]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"CDC42\",\n      \"RHOA\",\n      \"KIF5B\",\n      \"FGFR1\",\n      \"ARHGAP1\",\n      \"ARHGEF2\",\n      \"CDO1\",\n      \"LATS1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}