{"gene":"MYO9B","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2010,"finding":"Myo9b is a RhoGAP expressed in immune cells that spatially coordinates Rho activity to enable macrophage spreading, polarization, and lamellipodia formation. Myo9b-deficient macrophages fail to generate lamellipodia in response to chemoattractant and show severely impaired migration; pharmacological inhibition of Rho rescues the spreading/polarization defect, placing Myo9b upstream of RhoA in the motility pathway.","method":"Myo9b knockout mice; macrophage spreading/migration assays; Rho inhibitor rescue (epistasis); in vivo peritoneal recruitment assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO with defined cellular phenotype, pharmacological epistasis rescue, in vivo validation; replicated in spirit by multiple subsequent studies","pmids":["20566876"],"is_preprint":false},{"year":2015,"finding":"Myo9b is a ROBO-interacting protein that suppresses RhoA activity via its RhoGAP domain. The ROBO intracellular domain directly binds the Myo9b RhoGAP domain and inhibits its GAP activity, so SLIT-dependent ROBO activation leads to increased RhoA-GTP by relieving Myo9b-mediated RhoA suppression. Structural analysis identified a unique patch in the Myo9b RhoGAP domain that specifically recognizes RhoA.","method":"Co-immunoprecipitation (ROBO–Myo9b interaction); in vitro GAP inhibition assay; structural analysis of RhoGAP domain; RhoA-GTP pull-down; cell migration assays; murine tumor/metastasis model","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — structural analysis plus biochemical binding and functional GAP inhibition assays, in vitro and in vivo validation in single study","pmids":["26529257"],"is_preprint":false},{"year":2016,"finding":"Myo9b-RhoGAP accelerates RhoA GTP hydrolysis by a dual-arginine-finger mechanism: the first arginine finger inserts into the nucleotide-binding pocket of RhoA (canonical), while a second arginine finger anchors the Switch I loop of RhoA and stabilizes the transition state, compensating for the absence of the auxiliary asparagine found in canonical RhoGAP domains. Mutagenesis of either arginine finger impairs catalytic activity and cell migration.","method":"Crystal structure of Myo9b-RhoGAP in complex with GDP-bound RhoA and magnesium fluoride; active-site mutagenesis; in vitro GAP activity assay; cell migration assay","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with functional mutagenesis and in vitro enzymatic assay in one study","pmids":["27363609"],"is_preprint":false},{"year":2017,"finding":"The transcription factor KLF5 directly binds the Myo9b promoter and activates Myo9b transcription. In macrophages, KLF5-driven Myo9b expression is required for podosome formation (Myo9b colocalizes with F-actin, cortactin, vinculin, and Tks5 at podosomes) and migration. KLF5 knockdown increases RhoA-GTP, placing Myo9b downstream of KLF5 and upstream of RhoA inhibition.","method":"Luciferase reporter assay (KLF5 binding to Myo9b promoter); myeloid-specific KLF5 KO mice; gain/loss-of-function experiments; co-immunostaining; RhoA-GTP pull-down; macrophage migration and time-lapse imaging","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Moderate — luciferase reporter, KO mice with defined phenotype, RhoA-GTP measurement, and co-localization; multiple orthogonal methods in one study","pmids":["28115390"],"is_preprint":false},{"year":2020,"finding":"PKA and PKG phosphorylate Myo9b at serine 1354 in human platelets. This phosphorylation enhances Myo9b's GAP activity, leading to reduced RhoA-GTP levels. This mechanism mediates cyclic nucleotide-dependent inhibition of RhoA in platelets, as RhoA itself is not directly phosphorylated by PKA under these conditions.","method":"Phosphoproteomics of human platelets; Western blotting and Phos-tag gel electrophoresis; pull-down assays for GAP activity; transfected HEK293T cells as validation","journal":"Journal of thrombosis and haemostasis : JTH","confidence":"High","confidence_rationale":"Tier 2 / Moderate — phosphoproteomics plus biochemical GAP activity assay and site-specific phosphorylation verification with multiple methods","pmids":["32692911"],"is_preprint":false},{"year":2020,"finding":"Myo9b accumulates in lamellipodial extensions as a function of its motor activity (motor mutants fail to accumulate). Local, not global, GAP activity of Myo9b is required to rescue cell morphology and directional migration in Myo9b-deficient macrophage-like cells. Rac-induced actin polymerization recruits Myo9b, which then locally inhibits Rho at the leading edge.","method":"Myo9b-deficient HL-60-derived macrophages reconstituted with motor-dead and GAP-dead Myo9b mutants; live-cell imaging; cell migration assays; fluorescent Myo9b localization","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — structure–function with motor and GAP domain mutants in loss-of-function rescue experiments, multiple orthogonal readouts","pmids":["33268376"],"is_preprint":false},{"year":2012,"finding":"Myo9b is a critical RhoA GAP in cortical neurons: knockdown of Myo9b in cultured cortical neurons or developing cortex reduces dendrite length and number, and inhibition of RhoA/ROCK signaling rescues the dendritic morphology defects caused by Myo9b knockdown, placing Myo9b upstream of RhoA/ROCK in dendritic development.","method":"RNA interference knockdown in rat cortical neurons and in vivo cortex; dendritic morphology quantification; RhoA/ROCK inhibitor rescue epistasis","journal":"Cerebral cortex","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi KD with defined morphological phenotype and pharmacological epistasis; single lab, no biochemical RhoA-GTP measurement reported","pmids":["22250289"],"is_preprint":false},{"year":2017,"finding":"Myo9b knockout impairs bone growth in mice. In osteoblastic cells, Myo9b is distributed in stress fibers and focal adhesions; its loss causes poor cell spreading and detachment, and reduces IGF-1-induced spreading and chemotaxis (but not responses to PDGF or BMP-2). Loss of Myo9b redistributes activated IGF-1 receptor from stress fibers and focal adhesions into nuclei, suggesting Myo9b regulates IGF1R subcellular localization and accessibility.","method":"Myo9b KO mice (micro-CT, histomorphometry); primary osteogenic cell culture; RNAi knockdown of Myo9b in MC3T3-E1 cells; IGF-1 chemotaxis and spreading assays; immunofluorescence of IGF1R localization","journal":"Journal of bone and mineral research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse with defined phenotype plus cell-based receptor localization experiments; multiple methods but single lab","pmids":["28585695"],"is_preprint":false},{"year":2022,"finding":"Myo9b is required for ocular lens vesicle morphogenesis. Myo9b-deficient mice show microphthalmia and cataracts; embryonic lens placode invagination is shallow and conical rather than spherical, with mislocalized F-actin and adherens junctions, indicating Myo9b coordinates mechanical forces between epithelial cells during lens pit formation.","method":"Myo9b KO mouse embryo analysis; immunostaining of F-actin and adherens junctions; Pax6 expression control","journal":"Developmental dynamics","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — KO mouse with defined developmental phenotype and cytoskeletal staining; single lab, no biochemical RhoA-GTP measurement","pmids":["36008362"],"is_preprint":false},{"year":2022,"finding":"Rare recessive variants in MYO9B cause Charcot-Marie-Tooth disease type 2 (CMT2) and isolated optic atrophy. A variant in the MYO9B motor domain impairs protein expression level and motor activity. Myo9b-null mice have degenerating axons in sciatic nerves and optic nerves, indicating Myo9b motor function is essential for axon maintenance in both peripheral and central nervous system.","method":"Whole-exome sequencing and targeted NGS in CMT2 families; functional studies of motor domain variant (protein expression, motor activity assay); Myo9b-null mouse nerve histopathology","journal":"European journal of neurology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — human genetics plus motor activity functional assay and KO mouse axon degeneration; single study but multiple orthogonal approaches","pmids":["36260368"],"is_preprint":false},{"year":2023,"finding":"Myo9b regulates dendritic cell (DC) migration and T-cell priming. A 33-bp deletion in the Myo9b motor domain (in ALR mice) impairs DC phenotypic and functional maturation and prevents autoimmune diabetes progression in NOD mice. A human MYO9B R133Q polymorphism enhances DC function. Knock-in of the ALR Myo9b allele into NOD mice recapitulates impaired DC migration and T-cell priming.","method":"Genomic comparative analysis; Myo9b knock-in mouse models; DC migration and T-cell priming assays in vitro and in vivo; spontaneous diabetes incidence monitoring","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — knock-in mouse models with defined cellular and disease phenotypes, replicated in both mouse and human data, published in high-impact peer-reviewed journal","pmids":["37749140"],"is_preprint":false},{"year":2024,"finding":"MIRO2 binds MYO9B and cooperates with it to promote cancer cell invasion. Knockdown of MIRO2's binding partner MYO9B reduces tumor cell invasion and phenocopies MIRO2 depletion, resulting in increased active RhoA. Dual ablation of MIRO2 and RhoA fully rescues tumor cell invasion, and MIRO2 requires MYO9B to drive invasion, defining a MIRO2–MYO9B–RhoA axis in metastasis.","method":"Co-immunoprecipitation (MIRO2–MYO9B interaction); RNAi knockdown of MYO9B; RhoA-GTP measurement; dual MIRO2/RhoA knockdown epistasis; in vitro invasion assays; mouse metastasis models","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal binding, RhoA-GTP measurement, genetic epistasis, and in vivo validation; single lab","pmids":["39723893"],"is_preprint":false},{"year":2025,"finding":"Myo9b deficiency in head and neck squamous cell carcinoma (HNSC) cells upregulates HIF1α signaling, which in turn upregulates c-Myc, inducing stem-like phenotypes; c-Myc then upregulates STAT2 signaling, contributing to cisplatin resistance.","method":"Western blotting and immunostaining; CCK8 proliferation and Transwell migration assays; 3D Matrigel primary tumor cell culture; STAT2 inhibitor treatment","journal":"Biochimica et biophysica acta. General subjects","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, Western blotting and cell-based assays only, no direct biochemical link between MYO9B loss and HIF1α activation established","pmids":["40518028"],"is_preprint":false},{"year":2025,"finding":"RhoA GAP Myo9b regulates β2-integrin activation in neutrophils by controlling RhoA activity, which is required for chemokine- and selectin-induced talin-1 recruitment to β2-integrins. Myo9b deficiency causes RhoA overactivation, increases actin rearrangement, decreases neutrophil adhesion, crawling, and transmigration, and impairs neutrophil recruitment into the kidney during acute kidney injury.","method":"Myo9b KO mice; intravital microscopy (rolling, adhesion, crawling, transmigration); acute kidney injury models; talin-1 recruitment assays; RhoA-GTP measurement","journal":"Blood","confidence":"High","confidence_rationale":"Tier 2 / Moderate — KO mouse with defined mechanistic pathway (talin-1/β2-integrin), multiple in vivo and in vitro readouts, single lab","pmids":["40504998"],"is_preprint":false},{"year":2025,"finding":"CDK4 phosphorylates Myo9b at serine 1935 (S1935), and this phosphorylation activates Myo9b's RhoGAP function, thereby suppressing RhoA signaling and restricting TNBC cell migration. Loss or inhibition of CDK4 decreases Myo9b S1935 phosphorylation, enhances RhoA signaling, reorganizes actin networks, and increases cell migration.","method":"CRISPR/Cas9 CDK4 KO; CDK4/6 pharmacological inhibitor; phosphorylation site identification (S1935); RhoA activity assay; actin cytoskeleton imaging; migration assays in MDA-MB-231 cells","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — CRISPR KO plus pharmacological inhibition and phospho-site identification, single lab preprint not yet peer-reviewed","pmids":[],"is_preprint":true},{"year":2020,"finding":"Myo9b deficiency in cancer cells (lung) suppresses malignant pleural effusion development by inhibiting migration. In immune cells, Myo9b deficiency decreases TH1 cell differentiation and increases TH17 cell differentiation via a TSAd-dependent pathway: Myo9b loss enriches the H3K27me3 repressive mark at the TSAd promoter, reducing TSAd expression, which shifts naive T cell fate toward TH17.","method":"Myo9b-deficient mouse model; in vitro T-cell differentiation assays; mRNA sequencing; ChIP for H3K27me3; siRNA knockdown of TSAd; in vivo MPE model","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse plus chromatin mark and siRNA experiments with in vitro and in vivo readouts; single lab","pmids":["33046503"],"is_preprint":false}],"current_model":"MYO9B encodes an unconventional class IX single-headed myosin that simultaneously acts as an actin-based motor and a RhoA-specific GTPase-activating protein (RhoGAP), suppressing RhoA-GTP via a unique dual-arginine-finger catalytic mechanism; its motor activity recruits it to lamellipodia where local RhoA inhibition coordinates cell polarity, spreading, and directional migration in macrophages, neutrophils, and other cell types, while upstream regulators including SLIT/ROBO, KLF5, PKA/PKG-mediated phosphorylation at S1354, CDK4-mediated phosphorylation at S1935, and the mitochondrial GTPase MIRO2 modulate its GAP activity or localization to control RhoA signaling in diverse physiological and pathological contexts including immune cell trafficking, bone formation, neuronal dendrite growth, lens morphogenesis, and cancer invasion."},"narrative":{"mechanistic_narrative":"MYO9B is an unconventional myosin that couples actin-based motor function to RhoA-specific GTPase-activating (RhoGAP) activity, allowing it to spatially restrict RhoA signaling and thereby control cell spreading, polarity, and directional migration [PMID:20566876, PMID:33268376]. Its catalytic core accelerates RhoA GTP hydrolysis through a non-canonical dual-arginine-finger mechanism, in which a second arginine finger anchors the RhoA Switch I loop to stabilize the transition state in place of the auxiliary asparagine used by conventional RhoGAPs, while a unique surface patch confers RhoA specificity [PMID:26529257, PMID:27363609]. Motor activity targets MYO9B to lamellipodial extensions downstream of Rac-driven actin polymerization, where it delivers local rather than global RhoA suppression to organize the leading edge [PMID:33268376]. This RhoA-restricting activity is gated by multiple inputs: the SLIT-receptor ROBO directly binds the RhoGAP domain and inhibits its catalysis [PMID:26529257]; PKA/PKG phosphorylation at S1354 and CDK4 phosphorylation at S1935 enhance GAP activity [PMID:32692911]; the transcription factor KLF5 drives MYO9B expression [PMID:28115390]; and the GTPase MIRO2 partners with MYO9B to lower active RhoA during invasion [PMID:39723893]. Through this RhoA-centered control of the cytoskeleton, MYO9B governs macrophage podosome formation and migration [PMID:28115390], neutrophil β2-integrin/talin-1 activation and recruitment [PMID:40504998], dendritic cell maturation and T-cell priming [PMID:37749140], cortical neuron dendrite growth [PMID:22250289], osteoblast spreading and bone growth [PMID:28585695], lens vesicle morphogenesis [PMID:36008362], and tumor cell invasion [PMID:39723893]. Recessive MYO9B motor-domain variants that impair motor activity cause Charcot-Marie-Tooth disease type 2 and isolated optic atrophy, consistent with degenerating peripheral and optic axons in Myo9b-null mice [PMID:36260368].","teleology":[{"year":2010,"claim":"Established that Myo9b is a RhoGAP acting upstream of RhoA to enable immune cell motility, answering whether it functions as a positive or negative regulator of Rho-driven morphology.","evidence":"Myo9b knockout mice with macrophage spreading/migration assays and Rho-inhibitor epistasis rescue plus in vivo recruitment","pmids":["20566876"],"confidence":"High","gaps":["Did not resolve how Myo9b is spatially targeted within the cell","No structural basis for RhoA specificity"]},{"year":2012,"claim":"Extended the RhoA-suppressing role beyond immune cells, showing Myo9b drives dendritic morphogenesis through RhoA/ROCK in neurons.","evidence":"RNAi knockdown in rat cortical neurons and developing cortex with RhoA/ROCK inhibitor epistasis","pmids":["22250289"],"confidence":"Medium","gaps":["No direct RhoA-GTP measurement","Single lab, no biochemical confirmation of GAP activity in neurons"]},{"year":2015,"claim":"Defined an upstream regulatory input by showing ROBO directly binds and inhibits the Myo9b RhoGAP domain, linking SLIT/ROBO guidance signaling to RhoA control.","evidence":"Co-IP, in vitro GAP inhibition assay, structural analysis of the RhoGAP domain, and tumor metastasis models","pmids":["26529257"],"confidence":"High","gaps":["Stoichiometry and dynamics of ROBO-mediated inhibition in vivo unresolved","How motor activity and ROBO binding are integrated unknown"]},{"year":2016,"claim":"Resolved the catalytic mechanism, explaining how Myo9b achieves GAP activity without the canonical auxiliary asparagine via a dual-arginine-finger arrangement.","evidence":"Crystal structure of Myo9b-RhoGAP bound to GDP-RhoA and MgF, active-site mutagenesis, and GAP/migration assays","pmids":["27363609"],"confidence":"High","gaps":["Structure captures isolated GAP domain, not the full-length motor-GAP protein","Does not address regulatory phosphorylation effects on catalysis"]},{"year":2017,"claim":"Identified transcriptional and tissue-level controls: KLF5 directly activates Myo9b expression for podosome formation, and Myo9b is required for osteoblast adhesion and IGF1R localization in bone.","evidence":"KLF5 luciferase reporter and myeloid KO mice; Myo9b KO mice with osteogenic cell spreading and IGF1R immunofluorescence","pmids":["28115390","28585695"],"confidence":"High","gaps":["Mechanism linking Myo9b to IGF1R trafficking not biochemically defined","Whether bone phenotype is RhoA-dependent not directly tested"]},{"year":2020,"claim":"Demonstrated that motor activity localizes Myo9b to lamellipodia for local RhoA inhibition, and that phosphorylation tunes its GAP output, establishing spatial and post-translational regulation.","evidence":"Motor-dead/GAP-dead rescue in macrophage-like cells with live imaging; platelet phosphoproteomics identifying S1354 PKA/PKG phosphorylation with GAP assays","pmids":["33268376","32692911"],"confidence":"High","gaps":["How motor processivity and GAP catalysis are mechanically coupled remains unclear","S1354 phosphorylation effect on catalysis not structurally explained"]},{"year":2020,"claim":"Linked Myo9b to T-cell fate and cancer dissemination, showing its loss biases TH17 differentiation through chromatin-level TSAd repression and suppresses malignant pleural effusion.","evidence":"Myo9b-deficient mice, in vitro T-cell differentiation, mRNA-seq, H3K27me3 ChIP, TSAd siRNA, and an MPE model","pmids":["33046503"],"confidence":"Medium","gaps":["Connection between RhoGAP activity and H3K27me3 deposition at TSAd not established","Single lab"]},{"year":2022,"claim":"Established developmental and disease relevance through requirements in lens morphogenesis and human neuropathy, with motor-domain variants causing CMT2 and optic atrophy.","evidence":"Myo9b KO mouse lens analysis; whole-exome/NGS in CMT2 families with motor-domain variant functional assays and Myo9b-null nerve histopathology","pmids":["36008362","36260368"],"confidence":"Medium","gaps":["Whether axon and lens phenotypes are RhoA-dependent not directly shown","Variant effect on motor activity quantified in single study"]},{"year":2023,"claim":"Tied Myo9b motor function to dendritic cell migration and autoimmunity, with motor-domain alleles altering DC maturation and diabetes progression.","evidence":"Myo9b knock-in mouse models, DC migration and T-cell priming assays, and diabetes incidence monitoring with human polymorphism data","pmids":["37749140"],"confidence":"High","gaps":["RhoA-GTP consequences of the motor alleles in DCs not measured","Mechanism by which motor activity controls DC maturation not detailed"]},{"year":2024,"claim":"Defined a MIRO2-MYO9B-RhoA axis in cancer invasion, identifying a new direct partner that requires MYO9B to suppress RhoA.","evidence":"Reciprocal Co-IP, MYO9B RNAi, RhoA-GTP measurement, dual MIRO2/RhoA epistasis, invasion and metastasis models","pmids":["39723893"],"confidence":"Medium","gaps":["How MIRO2 binding modulates MYO9B catalysis or localization unknown","Single lab"]},{"year":2025,"claim":"Added CDK4 phosphorylation at S1935 and neutrophil β2-integrin control as further mechanisms tuning Myo9b's RhoA-restricting activity in migration.","evidence":"CDK4 CRISPR KO and inhibitors with S1935 phospho-site mapping (preprint); Myo9b KO mice with intravital microscopy and talin-1/β2-integrin recruitment assays","pmids":["40504998"],"confidence":"High","gaps":["CDK4-Myo9b axis from a preprint not yet peer-reviewed","Structural basis of S1935 activation not defined"]},{"year":null,"claim":"How Myo9b integrates simultaneous motor movement, RhoGAP catalysis, and the array of upstream regulators (ROBO, KLF5, MIRO2, PKA/PKG, CDK4) into a unified spatial RhoA-control circuit remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No full-length structure coupling motor and GAP domains","Quantitative model of local vs global RhoA suppression lacking","Tissue-specific regulator hierarchy not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0003774","term_label":"cytoskeletal motor activity","supporting_discovery_ids":[5,9]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[3,5,7]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[5,7,8]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[5,13]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,2]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[0,10,13,15]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[9,11,12]}],"complexes":[],"partners":["RHOA","ROBO1","MIRO2","KLF5","CDK4"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q13459","full_name":"Unconventional myosin-IXb","aliases":["Unconventional myosin-9b"],"length_aa":2157,"mass_kda":243.4,"function":"Myosins are actin-based motor molecules with ATPase activity. Unconventional myosins serve in intracellular movements. Binds actin with high affinity both in the absence and presence of ATP and its mechanochemical activity is inhibited by calcium ions (PubMed:9490638). Also acts as a GTPase activator for RHOA (PubMed:26529257, PubMed:9490638). Plays a role in the regulation of cell migration via its role as RHOA GTPase activator. This is regulated by its interaction with the SLIT2 receptor ROBO1; interaction with ROBO1 impairs interaction with RHOA and subsequent activation of RHOA GTPase activity, and thereby leads to increased levels of active, GTP-bound RHOA (PubMed:26529257)","subcellular_location":"Cytoplasm, cell cortex; Cytoplasm, perinuclear region; Cytoplasm, cytoskeleton","url":"https://www.uniprot.org/uniprotkb/Q13459/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MYO9B","classification":"Not Classified","n_dependent_lines":86,"n_total_lines":1208,"dependency_fraction":0.07119205298013245},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000099331","cell_line_id":"CID000595","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"membrane","grade":1}],"interactors":[{"gene":"ACTG1","stoichiometry":0.2},{"gene":"CALM1","stoichiometry":0.2},{"gene":"CALM2","stoichiometry":0.2},{"gene":"CALM3","stoichiometry":0.2},{"gene":"MYL6B","stoichiometry":0.2},{"gene":"DCAF8","stoichiometry":0.2},{"gene":"PJA1;PJA2","stoichiometry":0.2},{"gene":"NAP1L4","stoichiometry":0.2},{"gene":"TARBP2","stoichiometry":0.2},{"gene":"MYL6","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000595","total_profiled":1310},"omim":[{"mim_id":"609753","title":"CELIAC DISEASE, SUSCEPTIBILITY TO, 4; CELIAC4","url":"https://www.omim.org/entry/609753"},{"mim_id":"604875","title":"MYOSIN IXA; MYO9A","url":"https://www.omim.org/entry/604875"},{"mim_id":"604141","title":"ADP-RIBOSYLATION FACTOR GUANINE NUCLEOTIDE EXCHANGE FACTOR 1; ARFGEF1","url":"https://www.omim.org/entry/604141"},{"mim_id":"602129","title":"MYOSIN IXB; MYO9B","url":"https://www.omim.org/entry/602129"},{"mim_id":"212750","title":"CELIAC DISEASE, SUSCEPTIBILITY TO, 1; CELIAC1","url":"https://www.omim.org/entry/212750"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"lymphoid tissue","ntpm":145.0}],"url":"https://www.proteinatlas.org/search/MYO9B"},"hgnc":{"alias_symbol":[],"prev_symbol":["CELIAC4"]},"alphafold":{"accession":"Q13459","domains":[{"cath_id":"3.10.20.90","chopping":"18-139","consensus_level":"high","plddt":71.6081,"start":18,"end":139},{"cath_id":"1.20.58.530","chopping":"533-645","consensus_level":"medium","plddt":84.5588,"start":533,"end":645},{"cath_id":"-","chopping":"1505-1605","consensus_level":"high","plddt":77.7211,"start":1505,"end":1605},{"cath_id":"1.20.5","chopping":"942-1052","consensus_level":"medium","plddt":85.6989,"start":942,"end":1052}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q13459","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q13459-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q13459-F1-predicted_aligned_error_v6.png","plddt_mean":62.91},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MYO9B","jax_strain_url":"https://www.jax.org/strain/search?query=MYO9B"},"sequence":{"accession":"Q13459","fasta_url":"https://rest.uniprot.org/uniprotkb/Q13459.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q13459/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q13459"}},"corpus_meta":[{"pmid":"20566876","id":"PMC_20566876","title":"Motorized RhoGAP myosin IXb (Myo9b) controls cell shape and motility.","date":"2010","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/20566876","citation_count":105,"is_preprint":false},{"pmid":"26529257","id":"PMC_26529257","title":"Myo9b is a key player in SLIT/ROBO-mediated lung tumor suppression.","date":"2015","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/26529257","citation_count":75,"is_preprint":false},{"pmid":"16423886","id":"PMC_16423886","title":"Lack of association of MYO9B genetic variants with coeliac disease in a British cohort.","date":"2006","source":"Gut","url":"https://pubmed.ncbi.nlm.nih.gov/16423886","citation_count":54,"is_preprint":false},{"pmid":"28115390","id":"PMC_28115390","title":"Inhibition of KLF5-Myo9b-RhoA Pathway-Mediated Podosome Formation in Macrophages Ameliorates Abdominal Aortic Aneurysm.","date":"2017","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/28115390","citation_count":48,"is_preprint":false},{"pmid":"17967566","id":"PMC_17967566","title":"The MYO9B gene is a strong risk factor for developing refractory celiac disease.","date":"2007","source":"Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association","url":"https://pubmed.ncbi.nlm.nih.gov/17967566","citation_count":43,"is_preprint":false},{"pmid":"16720215","id":"PMC_16720215","title":"Association analysis of MYO9B gene polymorphisms with celiac disease in a Swedish/Norwegian cohort.","date":"2006","source":"Human immunology","url":"https://pubmed.ncbi.nlm.nih.gov/16720215","citation_count":42,"is_preprint":false},{"pmid":"17944996","id":"PMC_17944996","title":"The association of MYO9B gene in Italian patients with inflammatory bowel diseases.","date":"2007","source":"Alimentary pharmacology & therapeutics","url":"https://pubmed.ncbi.nlm.nih.gov/17944996","citation_count":32,"is_preprint":false},{"pmid":"17584584","id":"PMC_17584584","title":"MYO9B gene polymorphisms are associated with autoimmune diseases in Spanish population.","date":"2007","source":"Human immunology","url":"https://pubmed.ncbi.nlm.nih.gov/17584584","citation_count":27,"is_preprint":false},{"pmid":"16943798","id":"PMC_16943798","title":"A family-based study does not confirm the association of MYO9B with celiac disease in the Italian population.","date":"2006","source":"Genes and immunity","url":"https://pubmed.ncbi.nlm.nih.gov/16943798","citation_count":27,"is_preprint":false},{"pmid":"22250289","id":"PMC_22250289","title":"Myo9b and RICS modulate dendritic morphology of cortical neurons.","date":"2012","source":"Cerebral cortex (New York, N.Y. : 1991)","url":"https://pubmed.ncbi.nlm.nih.gov/22250289","citation_count":21,"is_preprint":false},{"pmid":"17176439","id":"PMC_17176439","title":"No evidence of association of the MYO9B polymorphisms with celiac disease in the Spanish population.","date":"2006","source":"Tissue antigens","url":"https://pubmed.ncbi.nlm.nih.gov/17176439","citation_count":21,"is_preprint":false},{"pmid":"17948900","id":"PMC_17948900","title":"Is MYO9B the missing link between schizophrenia and celiac disease?","date":"2008","source":"American journal of medical genetics. 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An association study in a cohort of South Italian children.","date":"2007","source":"Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver","url":"https://pubmed.ncbi.nlm.nih.gov/17267307","citation_count":20,"is_preprint":false},{"pmid":"16948647","id":"PMC_16948647","title":"Association analysis of MYO9B gene polymorphisms and inflammatory bowel disease in a Norwegian cohort.","date":"2006","source":"Tissue antigens","url":"https://pubmed.ncbi.nlm.nih.gov/16948647","citation_count":18,"is_preprint":false},{"pmid":"32692911","id":"PMC_32692911","title":"The RhoA regulators Myo9b and GEF-H1 are targets of cyclic nucleotide-dependent kinases in platelets.","date":"2020","source":"Journal of thrombosis and haemostasis : JTH","url":"https://pubmed.ncbi.nlm.nih.gov/32692911","citation_count":18,"is_preprint":false},{"pmid":"33268376","id":"PMC_33268376","title":"Local Myo9b RhoGAP activity regulates cell motility.","date":"2020","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/33268376","citation_count":17,"is_preprint":false},{"pmid":"10580159","id":"PMC_10580159","title":"Cloning of the murine unconventional myosin gene Myo9b and identification of alternative splicing.","date":"1999","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/10580159","citation_count":17,"is_preprint":false},{"pmid":"18361936","id":"PMC_18361936","title":"Association of MYO9B haplotype with type 1 diabetes.","date":"2008","source":"Human immunology","url":"https://pubmed.ncbi.nlm.nih.gov/18361936","citation_count":17,"is_preprint":false},{"pmid":"27363609","id":"PMC_27363609","title":"Noncanonical Myo9b-RhoGAP Accelerates RhoA GTP Hydrolysis by a Dual-Arginine-Finger Mechanism.","date":"2016","source":"Journal of molecular 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1950)","url":"https://pubmed.ncbi.nlm.nih.gov/33046503","citation_count":14,"is_preprint":false},{"pmid":"37749140","id":"PMC_37749140","title":"Myo9b mutations are associated with altered dendritic cell functions and increased susceptibility to autoimmune diabetes onset.","date":"2023","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/37749140","citation_count":13,"is_preprint":false},{"pmid":"27435931","id":"PMC_27435931","title":"A meta-analysis of the relationship between MYO9B gene polymorphisms and susceptibility to Crohn's disease and ulcerative colitis.","date":"2016","source":"Human immunology","url":"https://pubmed.ncbi.nlm.nih.gov/27435931","citation_count":13,"is_preprint":false},{"pmid":"22954106","id":"PMC_22954106","title":"Myo9B is associated with an increased risk of Barrett's esophagus and esophageal adenocarcinoma.","date":"2012","source":"Scandinavian journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/22954106","citation_count":13,"is_preprint":false},{"pmid":"23368647","id":"PMC_23368647","title":"Frequency of MYO9B polymorphisms in celiac patients and controls.","date":"2012","source":"Revista espanola de enfermedades digestivas","url":"https://pubmed.ncbi.nlm.nih.gov/23368647","citation_count":11,"is_preprint":false},{"pmid":"36260368","id":"PMC_36260368","title":"Mutations in MYO9B are associated with Charcot-Marie-Tooth disease type 2 neuropathies and isolated optic atrophy.","date":"2022","source":"European journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/36260368","citation_count":9,"is_preprint":false},{"pmid":"27556856","id":"PMC_27556856","title":"MYO9B gene polymorphisms are associated with the risk of inflammatory bowel diseases.","date":"2016","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/27556856","citation_count":8,"is_preprint":false},{"pmid":"28627089","id":"PMC_28627089","title":"Analysis of PTPN22, ZFAT and MYO9B polymorphisms in Turner Syndrome and risk of autoimmune disease.","date":"2017","source":"International journal of immunogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/28627089","citation_count":8,"is_preprint":false},{"pmid":"26628973","id":"PMC_26628973","title":"Association between the MYO9B polymorphisms and celiac disease risk: a meta-analysis.","date":"2015","source":"International journal of clinical and experimental medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26628973","citation_count":8,"is_preprint":false},{"pmid":"27219348","id":"PMC_27219348","title":"Lack of Association between MYO9B Gene Polymorphisms and Susceptibility to Coeliac Disease in Caucasians: Evidence from a Meta-Analysis.","date":"2016","source":"Immunological investigations","url":"https://pubmed.ncbi.nlm.nih.gov/27219348","citation_count":6,"is_preprint":false},{"pmid":"21688385","id":"PMC_21688385","title":"No association observed between schizophrenia and non-HLA coeliac disease genes: integration with the initial MYO9B association with coeliac disease.","date":"2011","source":"American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21688385","citation_count":5,"is_preprint":false},{"pmid":"40504998","id":"PMC_40504998","title":"RhoA GAP Myo9b regulates β2-integrin activity and neutrophil recruitment during murine acute kidney injury.","date":"2025","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/40504998","citation_count":4,"is_preprint":false},{"pmid":"37675403","id":"PMC_37675403","title":"The myosin and RhoGAP MYO9B influences osteocyte dendrite growth and responses to mechanical stimuli.","date":"2023","source":"Frontiers in bioengineering and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/37675403","citation_count":4,"is_preprint":false},{"pmid":"39723893","id":"PMC_39723893","title":"MIRO2 promotes cancer invasion and metastasis via MYO9B suppression of RhoA activity.","date":"2024","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/39723893","citation_count":4,"is_preprint":false},{"pmid":"24966617","id":"PMC_24966617","title":"Association of MYO9B gene polymorphisms with inflammatory bowel disease in Chinese Han population.","date":"2014","source":"World journal of gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/24966617","citation_count":4,"is_preprint":false},{"pmid":"19142207","id":"PMC_19142207","title":"MYO9B polymorphisms in multiple sclerosis.","date":"2009","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/19142207","citation_count":4,"is_preprint":false},{"pmid":"36008362","id":"PMC_36008362","title":"The RhoGAP-myosin Myo9b regulates ocular lens pit morphogenesis.","date":"2022","source":"Developmental dynamics : an official publication of the American Association of Anatomists","url":"https://pubmed.ncbi.nlm.nih.gov/36008362","citation_count":3,"is_preprint":false},{"pmid":"34880655","id":"PMC_34880655","title":"The Correlation Between MYO9B Gene Polymorphism and Inflammatory Bowel Disease in the Guangxi Zhuang Population.","date":"2021","source":"International journal of general medicine","url":"https://pubmed.ncbi.nlm.nih.gov/34880655","citation_count":2,"is_preprint":false},{"pmid":"25710847","id":"PMC_25710847","title":"Lack of genetic association between the MYO9B locus and schizophrenia in a Chinese population.","date":"2015","source":"Psychiatric genetics","url":"https://pubmed.ncbi.nlm.nih.gov/25710847","citation_count":1,"is_preprint":false},{"pmid":"40518028","id":"PMC_40518028","title":"MYO9B deficiency promoted head and neck tumor progression through HIF1α/MYC/STAT2 signaling pathway.","date":"2025","source":"Biochimica et biophysica acta. General subjects","url":"https://pubmed.ncbi.nlm.nih.gov/40518028","citation_count":0,"is_preprint":false},{"pmid":"41186777","id":"PMC_41186777","title":"Circ-MYO9B modulates metabolic pathways in nonalcoholic steatohepatitis via miR-193b-5p.","date":"2025","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/41186777","citation_count":0,"is_preprint":false},{"pmid":"41380525","id":"PMC_41380525","title":"Site-Specific alterations in bone characteristics and mechanical properties in MYO9B-Deficient mice.","date":"2025","source":"Journal of biomechanics","url":"https://pubmed.ncbi.nlm.nih.gov/41380525","citation_count":0,"is_preprint":false},{"pmid":"40382695","id":"PMC_40382695","title":"First Iranian Family with a Novel Missense Variant in MYO9B Gene Causing Charcot-Marie-Tooth Disease.","date":"2025","source":"Archives of Iranian medicine","url":"https://pubmed.ncbi.nlm.nih.gov/40382695","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.08.06.668850","title":"CDK4 Restricts Triple-Negative Breast Cancer Cell Migration via Phosphorylation-Driven Activation of Myo9b RhoGAP Function","date":"2025-08-08","source":"bioRxiv","url":"https://doi.org/10.1101/2025.08.06.668850","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":23841,"output_tokens":4655,"usd":0.070674,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":12700,"output_tokens":3959,"usd":0.081238,"stage2_stop_reason":"end_turn"},"total_usd":0.151912,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"Myo9b is a RhoGAP expressed in immune cells that spatially coordinates Rho activity to enable macrophage spreading, polarization, and lamellipodia formation. Myo9b-deficient macrophages fail to generate lamellipodia in response to chemoattractant and show severely impaired migration; pharmacological inhibition of Rho rescues the spreading/polarization defect, placing Myo9b upstream of RhoA in the motility pathway.\",\n      \"method\": \"Myo9b knockout mice; macrophage spreading/migration assays; Rho inhibitor rescue (epistasis); in vivo peritoneal recruitment assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO with defined cellular phenotype, pharmacological epistasis rescue, in vivo validation; replicated in spirit by multiple subsequent studies\",\n      \"pmids\": [\"20566876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Myo9b is a ROBO-interacting protein that suppresses RhoA activity via its RhoGAP domain. The ROBO intracellular domain directly binds the Myo9b RhoGAP domain and inhibits its GAP activity, so SLIT-dependent ROBO activation leads to increased RhoA-GTP by relieving Myo9b-mediated RhoA suppression. Structural analysis identified a unique patch in the Myo9b RhoGAP domain that specifically recognizes RhoA.\",\n      \"method\": \"Co-immunoprecipitation (ROBO–Myo9b interaction); in vitro GAP inhibition assay; structural analysis of RhoGAP domain; RhoA-GTP pull-down; cell migration assays; murine tumor/metastasis model\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — structural analysis plus biochemical binding and functional GAP inhibition assays, in vitro and in vivo validation in single study\",\n      \"pmids\": [\"26529257\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Myo9b-RhoGAP accelerates RhoA GTP hydrolysis by a dual-arginine-finger mechanism: the first arginine finger inserts into the nucleotide-binding pocket of RhoA (canonical), while a second arginine finger anchors the Switch I loop of RhoA and stabilizes the transition state, compensating for the absence of the auxiliary asparagine found in canonical RhoGAP domains. Mutagenesis of either arginine finger impairs catalytic activity and cell migration.\",\n      \"method\": \"Crystal structure of Myo9b-RhoGAP in complex with GDP-bound RhoA and magnesium fluoride; active-site mutagenesis; in vitro GAP activity assay; cell migration assay\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with functional mutagenesis and in vitro enzymatic assay in one study\",\n      \"pmids\": [\"27363609\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The transcription factor KLF5 directly binds the Myo9b promoter and activates Myo9b transcription. In macrophages, KLF5-driven Myo9b expression is required for podosome formation (Myo9b colocalizes with F-actin, cortactin, vinculin, and Tks5 at podosomes) and migration. KLF5 knockdown increases RhoA-GTP, placing Myo9b downstream of KLF5 and upstream of RhoA inhibition.\",\n      \"method\": \"Luciferase reporter assay (KLF5 binding to Myo9b promoter); myeloid-specific KLF5 KO mice; gain/loss-of-function experiments; co-immunostaining; RhoA-GTP pull-down; macrophage migration and time-lapse imaging\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — luciferase reporter, KO mice with defined phenotype, RhoA-GTP measurement, and co-localization; multiple orthogonal methods in one study\",\n      \"pmids\": [\"28115390\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PKA and PKG phosphorylate Myo9b at serine 1354 in human platelets. This phosphorylation enhances Myo9b's GAP activity, leading to reduced RhoA-GTP levels. This mechanism mediates cyclic nucleotide-dependent inhibition of RhoA in platelets, as RhoA itself is not directly phosphorylated by PKA under these conditions.\",\n      \"method\": \"Phosphoproteomics of human platelets; Western blotting and Phos-tag gel electrophoresis; pull-down assays for GAP activity; transfected HEK293T cells as validation\",\n      \"journal\": \"Journal of thrombosis and haemostasis : JTH\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — phosphoproteomics plus biochemical GAP activity assay and site-specific phosphorylation verification with multiple methods\",\n      \"pmids\": [\"32692911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Myo9b accumulates in lamellipodial extensions as a function of its motor activity (motor mutants fail to accumulate). Local, not global, GAP activity of Myo9b is required to rescue cell morphology and directional migration in Myo9b-deficient macrophage-like cells. Rac-induced actin polymerization recruits Myo9b, which then locally inhibits Rho at the leading edge.\",\n      \"method\": \"Myo9b-deficient HL-60-derived macrophages reconstituted with motor-dead and GAP-dead Myo9b mutants; live-cell imaging; cell migration assays; fluorescent Myo9b localization\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — structure–function with motor and GAP domain mutants in loss-of-function rescue experiments, multiple orthogonal readouts\",\n      \"pmids\": [\"33268376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Myo9b is a critical RhoA GAP in cortical neurons: knockdown of Myo9b in cultured cortical neurons or developing cortex reduces dendrite length and number, and inhibition of RhoA/ROCK signaling rescues the dendritic morphology defects caused by Myo9b knockdown, placing Myo9b upstream of RhoA/ROCK in dendritic development.\",\n      \"method\": \"RNA interference knockdown in rat cortical neurons and in vivo cortex; dendritic morphology quantification; RhoA/ROCK inhibitor rescue epistasis\",\n      \"journal\": \"Cerebral cortex\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi KD with defined morphological phenotype and pharmacological epistasis; single lab, no biochemical RhoA-GTP measurement reported\",\n      \"pmids\": [\"22250289\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Myo9b knockout impairs bone growth in mice. In osteoblastic cells, Myo9b is distributed in stress fibers and focal adhesions; its loss causes poor cell spreading and detachment, and reduces IGF-1-induced spreading and chemotaxis (but not responses to PDGF or BMP-2). Loss of Myo9b redistributes activated IGF-1 receptor from stress fibers and focal adhesions into nuclei, suggesting Myo9b regulates IGF1R subcellular localization and accessibility.\",\n      \"method\": \"Myo9b KO mice (micro-CT, histomorphometry); primary osteogenic cell culture; RNAi knockdown of Myo9b in MC3T3-E1 cells; IGF-1 chemotaxis and spreading assays; immunofluorescence of IGF1R localization\",\n      \"journal\": \"Journal of bone and mineral research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse with defined phenotype plus cell-based receptor localization experiments; multiple methods but single lab\",\n      \"pmids\": [\"28585695\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Myo9b is required for ocular lens vesicle morphogenesis. Myo9b-deficient mice show microphthalmia and cataracts; embryonic lens placode invagination is shallow and conical rather than spherical, with mislocalized F-actin and adherens junctions, indicating Myo9b coordinates mechanical forces between epithelial cells during lens pit formation.\",\n      \"method\": \"Myo9b KO mouse embryo analysis; immunostaining of F-actin and adherens junctions; Pax6 expression control\",\n      \"journal\": \"Developmental dynamics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — KO mouse with defined developmental phenotype and cytoskeletal staining; single lab, no biochemical RhoA-GTP measurement\",\n      \"pmids\": [\"36008362\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Rare recessive variants in MYO9B cause Charcot-Marie-Tooth disease type 2 (CMT2) and isolated optic atrophy. A variant in the MYO9B motor domain impairs protein expression level and motor activity. Myo9b-null mice have degenerating axons in sciatic nerves and optic nerves, indicating Myo9b motor function is essential for axon maintenance in both peripheral and central nervous system.\",\n      \"method\": \"Whole-exome sequencing and targeted NGS in CMT2 families; functional studies of motor domain variant (protein expression, motor activity assay); Myo9b-null mouse nerve histopathology\",\n      \"journal\": \"European journal of neurology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — human genetics plus motor activity functional assay and KO mouse axon degeneration; single study but multiple orthogonal approaches\",\n      \"pmids\": [\"36260368\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Myo9b regulates dendritic cell (DC) migration and T-cell priming. A 33-bp deletion in the Myo9b motor domain (in ALR mice) impairs DC phenotypic and functional maturation and prevents autoimmune diabetes progression in NOD mice. A human MYO9B R133Q polymorphism enhances DC function. Knock-in of the ALR Myo9b allele into NOD mice recapitulates impaired DC migration and T-cell priming.\",\n      \"method\": \"Genomic comparative analysis; Myo9b knock-in mouse models; DC migration and T-cell priming assays in vitro and in vivo; spontaneous diabetes incidence monitoring\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — knock-in mouse models with defined cellular and disease phenotypes, replicated in both mouse and human data, published in high-impact peer-reviewed journal\",\n      \"pmids\": [\"37749140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MIRO2 binds MYO9B and cooperates with it to promote cancer cell invasion. Knockdown of MIRO2's binding partner MYO9B reduces tumor cell invasion and phenocopies MIRO2 depletion, resulting in increased active RhoA. Dual ablation of MIRO2 and RhoA fully rescues tumor cell invasion, and MIRO2 requires MYO9B to drive invasion, defining a MIRO2–MYO9B–RhoA axis in metastasis.\",\n      \"method\": \"Co-immunoprecipitation (MIRO2–MYO9B interaction); RNAi knockdown of MYO9B; RhoA-GTP measurement; dual MIRO2/RhoA knockdown epistasis; in vitro invasion assays; mouse metastasis models\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal binding, RhoA-GTP measurement, genetic epistasis, and in vivo validation; single lab\",\n      \"pmids\": [\"39723893\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Myo9b deficiency in head and neck squamous cell carcinoma (HNSC) cells upregulates HIF1α signaling, which in turn upregulates c-Myc, inducing stem-like phenotypes; c-Myc then upregulates STAT2 signaling, contributing to cisplatin resistance.\",\n      \"method\": \"Western blotting and immunostaining; CCK8 proliferation and Transwell migration assays; 3D Matrigel primary tumor cell culture; STAT2 inhibitor treatment\",\n      \"journal\": \"Biochimica et biophysica acta. General subjects\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, Western blotting and cell-based assays only, no direct biochemical link between MYO9B loss and HIF1α activation established\",\n      \"pmids\": [\"40518028\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RhoA GAP Myo9b regulates β2-integrin activation in neutrophils by controlling RhoA activity, which is required for chemokine- and selectin-induced talin-1 recruitment to β2-integrins. Myo9b deficiency causes RhoA overactivation, increases actin rearrangement, decreases neutrophil adhesion, crawling, and transmigration, and impairs neutrophil recruitment into the kidney during acute kidney injury.\",\n      \"method\": \"Myo9b KO mice; intravital microscopy (rolling, adhesion, crawling, transmigration); acute kidney injury models; talin-1 recruitment assays; RhoA-GTP measurement\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse with defined mechanistic pathway (talin-1/β2-integrin), multiple in vivo and in vitro readouts, single lab\",\n      \"pmids\": [\"40504998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CDK4 phosphorylates Myo9b at serine 1935 (S1935), and this phosphorylation activates Myo9b's RhoGAP function, thereby suppressing RhoA signaling and restricting TNBC cell migration. Loss or inhibition of CDK4 decreases Myo9b S1935 phosphorylation, enhances RhoA signaling, reorganizes actin networks, and increases cell migration.\",\n      \"method\": \"CRISPR/Cas9 CDK4 KO; CDK4/6 pharmacological inhibitor; phosphorylation site identification (S1935); RhoA activity assay; actin cytoskeleton imaging; migration assays in MDA-MB-231 cells\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — CRISPR KO plus pharmacological inhibition and phospho-site identification, single lab preprint not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Myo9b deficiency in cancer cells (lung) suppresses malignant pleural effusion development by inhibiting migration. In immune cells, Myo9b deficiency decreases TH1 cell differentiation and increases TH17 cell differentiation via a TSAd-dependent pathway: Myo9b loss enriches the H3K27me3 repressive mark at the TSAd promoter, reducing TSAd expression, which shifts naive T cell fate toward TH17.\",\n      \"method\": \"Myo9b-deficient mouse model; in vitro T-cell differentiation assays; mRNA sequencing; ChIP for H3K27me3; siRNA knockdown of TSAd; in vivo MPE model\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse plus chromatin mark and siRNA experiments with in vitro and in vivo readouts; single lab\",\n      \"pmids\": [\"33046503\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MYO9B encodes an unconventional class IX single-headed myosin that simultaneously acts as an actin-based motor and a RhoA-specific GTPase-activating protein (RhoGAP), suppressing RhoA-GTP via a unique dual-arginine-finger catalytic mechanism; its motor activity recruits it to lamellipodia where local RhoA inhibition coordinates cell polarity, spreading, and directional migration in macrophages, neutrophils, and other cell types, while upstream regulators including SLIT/ROBO, KLF5, PKA/PKG-mediated phosphorylation at S1354, CDK4-mediated phosphorylation at S1935, and the mitochondrial GTPase MIRO2 modulate its GAP activity or localization to control RhoA signaling in diverse physiological and pathological contexts including immune cell trafficking, bone formation, neuronal dendrite growth, lens morphogenesis, and cancer invasion.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MYO9B is an unconventional myosin that couples actin-based motor function to RhoA-specific GTPase-activating (RhoGAP) activity, allowing it to spatially restrict RhoA signaling and thereby control cell spreading, polarity, and directional migration [#0, #5]. Its catalytic core accelerates RhoA GTP hydrolysis through a non-canonical dual-arginine-finger mechanism, in which a second arginine finger anchors the RhoA Switch I loop to stabilize the transition state in place of the auxiliary asparagine used by conventional RhoGAPs, while a unique surface patch confers RhoA specificity [#1, #2]. Motor activity targets MYO9B to lamellipodial extensions downstream of Rac-driven actin polymerization, where it delivers local rather than global RhoA suppression to organize the leading edge [#5]. This RhoA-restricting activity is gated by multiple inputs: the SLIT-receptor ROBO directly binds the RhoGAP domain and inhibits its catalysis [#1]; PKA/PKG phosphorylation at S1354 and CDK4 phosphorylation at S1935 enhance GAP activity [#4, #14]; the transcription factor KLF5 drives MYO9B expression [#3]; and the GTPase MIRO2 partners with MYO9B to lower active RhoA during invasion [#11]. Through this RhoA-centered control of the cytoskeleton, MYO9B governs macrophage podosome formation and migration [#3], neutrophil β2-integrin/talin-1 activation and recruitment [#13], dendritic cell maturation and T-cell priming [#10], cortical neuron dendrite growth [#6], osteoblast spreading and bone growth [#7], lens vesicle morphogenesis [#8], and tumor cell invasion [#11]. Recessive MYO9B motor-domain variants that impair motor activity cause Charcot-Marie-Tooth disease type 2 and isolated optic atrophy, consistent with degenerating peripheral and optic axons in Myo9b-null mice [#9].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established that Myo9b is a RhoGAP acting upstream of RhoA to enable immune cell motility, answering whether it functions as a positive or negative regulator of Rho-driven morphology.\",\n      \"evidence\": \"Myo9b knockout mice with macrophage spreading/migration assays and Rho-inhibitor epistasis rescue plus in vivo recruitment\",\n      \"pmids\": [\"20566876\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve how Myo9b is spatially targeted within the cell\", \"No structural basis for RhoA specificity\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Extended the RhoA-suppressing role beyond immune cells, showing Myo9b drives dendritic morphogenesis through RhoA/ROCK in neurons.\",\n      \"evidence\": \"RNAi knockdown in rat cortical neurons and developing cortex with RhoA/ROCK inhibitor epistasis\",\n      \"pmids\": [\"22250289\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct RhoA-GTP measurement\", \"Single lab, no biochemical confirmation of GAP activity in neurons\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined an upstream regulatory input by showing ROBO directly binds and inhibits the Myo9b RhoGAP domain, linking SLIT/ROBO guidance signaling to RhoA control.\",\n      \"evidence\": \"Co-IP, in vitro GAP inhibition assay, structural analysis of the RhoGAP domain, and tumor metastasis models\",\n      \"pmids\": [\"26529257\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and dynamics of ROBO-mediated inhibition in vivo unresolved\", \"How motor activity and ROBO binding are integrated unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Resolved the catalytic mechanism, explaining how Myo9b achieves GAP activity without the canonical auxiliary asparagine via a dual-arginine-finger arrangement.\",\n      \"evidence\": \"Crystal structure of Myo9b-RhoGAP bound to GDP-RhoA and MgF, active-site mutagenesis, and GAP/migration assays\",\n      \"pmids\": [\"27363609\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure captures isolated GAP domain, not the full-length motor-GAP protein\", \"Does not address regulatory phosphorylation effects on catalysis\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified transcriptional and tissue-level controls: KLF5 directly activates Myo9b expression for podosome formation, and Myo9b is required for osteoblast adhesion and IGF1R localization in bone.\",\n      \"evidence\": \"KLF5 luciferase reporter and myeloid KO mice; Myo9b KO mice with osteogenic cell spreading and IGF1R immunofluorescence\",\n      \"pmids\": [\"28115390\", \"28585695\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism linking Myo9b to IGF1R trafficking not biochemically defined\", \"Whether bone phenotype is RhoA-dependent not directly tested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Demonstrated that motor activity localizes Myo9b to lamellipodia for local RhoA inhibition, and that phosphorylation tunes its GAP output, establishing spatial and post-translational regulation.\",\n      \"evidence\": \"Motor-dead/GAP-dead rescue in macrophage-like cells with live imaging; platelet phosphoproteomics identifying S1354 PKA/PKG phosphorylation with GAP assays\",\n      \"pmids\": [\"33268376\", \"32692911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How motor processivity and GAP catalysis are mechanically coupled remains unclear\", \"S1354 phosphorylation effect on catalysis not structurally explained\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked Myo9b to T-cell fate and cancer dissemination, showing its loss biases TH17 differentiation through chromatin-level TSAd repression and suppresses malignant pleural effusion.\",\n      \"evidence\": \"Myo9b-deficient mice, in vitro T-cell differentiation, mRNA-seq, H3K27me3 ChIP, TSAd siRNA, and an MPE model\",\n      \"pmids\": [\"33046503\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Connection between RhoGAP activity and H3K27me3 deposition at TSAd not established\", \"Single lab\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Established developmental and disease relevance through requirements in lens morphogenesis and human neuropathy, with motor-domain variants causing CMT2 and optic atrophy.\",\n      \"evidence\": \"Myo9b KO mouse lens analysis; whole-exome/NGS in CMT2 families with motor-domain variant functional assays and Myo9b-null nerve histopathology\",\n      \"pmids\": [\"36008362\", \"36260368\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether axon and lens phenotypes are RhoA-dependent not directly shown\", \"Variant effect on motor activity quantified in single study\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Tied Myo9b motor function to dendritic cell migration and autoimmunity, with motor-domain alleles altering DC maturation and diabetes progression.\",\n      \"evidence\": \"Myo9b knock-in mouse models, DC migration and T-cell priming assays, and diabetes incidence monitoring with human polymorphism data\",\n      \"pmids\": [\"37749140\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"RhoA-GTP consequences of the motor alleles in DCs not measured\", \"Mechanism by which motor activity controls DC maturation not detailed\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined a MIRO2-MYO9B-RhoA axis in cancer invasion, identifying a new direct partner that requires MYO9B to suppress RhoA.\",\n      \"evidence\": \"Reciprocal Co-IP, MYO9B RNAi, RhoA-GTP measurement, dual MIRO2/RhoA epistasis, invasion and metastasis models\",\n      \"pmids\": [\"39723893\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How MIRO2 binding modulates MYO9B catalysis or localization unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Added CDK4 phosphorylation at S1935 and neutrophil β2-integrin control as further mechanisms tuning Myo9b's RhoA-restricting activity in migration.\",\n      \"evidence\": \"CDK4 CRISPR KO and inhibitors with S1935 phospho-site mapping (preprint); Myo9b KO mice with intravital microscopy and talin-1/β2-integrin recruitment assays\",\n      \"pmids\": [\"40504998\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"CDK4-Myo9b axis from a preprint not yet peer-reviewed\", \"Structural basis of S1935 activation not defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How Myo9b integrates simultaneous motor movement, RhoGAP catalysis, and the array of upstream regulators (ROBO, KLF5, MIRO2, PKA/PKG, CDK4) into a unified spatial RhoA-control circuit remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No full-length structure coupling motor and GAP domains\", \"Quantitative model of local vs global RhoA suppression lacking\", \"Tissue-specific regulator hierarchy not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0003774\", \"supporting_discovery_ids\": [5, 9]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [3, 5, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [5, 7, 8]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5, 13]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [0, 10, 13, 15]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [9, 11, 12]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"RHOA\", \"ROBO1\", \"MIRO2\", \"KLF5\", \"CDK4\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}