{"gene":"RHOB","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":1999,"finding":"RhoB localizes exclusively to the cytosolic face of endocytic vesicles (not the plasma membrane like RhoA) and acts through the RhoA effector PRK1, which RhoB binds and targets to the endosomal compartment, to regulate the kinetics of EGF receptor intracellular trafficking.","method":"Subcellular localization studies, co-immunoprecipitation/binding assays, dominant-active/dominant-negative mutant expression, receptor trafficking assays","journal":"Current biology : CB","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — localization by imaging, binding interaction demonstrated, functional consequence on EGFR trafficking shown; single lab, multiple orthogonal methods","pmids":["10508588"],"is_preprint":false},{"year":1999,"finding":"FTI treatment causes loss of farnesylated RhoB and gain of geranylgeranylated RhoB (RhoB-GG); ectopic RhoB-GG in Ras-transformed cells induces phenotypic reversion, growth inhibition, and p21WAF1 activation, demonstrating that gain of RhoB-GG is sufficient to mediate FTI-induced cell growth inhibition in transformed but not normal cells.","method":"Ectopic expression of RhoB-GG mutant in Ras-transformed cells, colony assay, cell growth assay, Western blot for p21WAF1","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal functional assays, replicated across multiple labs in subsequent papers","pmids":["10022870"],"is_preprint":false},{"year":1999,"finding":"Geranylgeranylated RhoB (RhoB-GG) suppresses human tumor cell proliferation by inducing p21WAF1 in a p53-dependent manner, and promotes apoptosis and G2-M accumulation in a p53-independent manner in human carcinoma cells.","method":"Ectopic expression of RhoB-GG in FTI-sensitive vs. resistant human carcinoma cells, cell cycle analysis, apoptosis assay, p21WAF1 Western blot in p53-null cells","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple human cell lines tested, multiple readouts; single lab","pmids":["10554025"],"is_preprint":false},{"year":2000,"finding":"RhoB-null fibroblasts (rhoB-/-) transformed by E1A+H-Ras are defective in FTI-induced apoptosis in vitro and in vivo, and show impaired antitumor responses in xenograft assays, providing genetic proof that RhoB-GG is a crucial mediator of FTI antineoplastic effects.","method":"Homozygous rhoB gene deletion, E1A+H-Ras cotransformation, FTI treatment, apoptosis assay in vitro, xenograft tumor assay in vivo","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout model with multiple functional readouts in vitro and in vivo; rigorous loss-of-function approach","pmids":["10913192"],"is_preprint":false},{"year":2000,"finding":"Both farnesylated (RhoB-F) and geranylgeranylated (RhoB-GG) forms of RhoB inhibit anchorage-dependent and -independent growth, induce apoptosis, inhibit constitutive Erk and IGF-1-stimulated Akt activation, and suppress tumor growth in nude mice in several human cancer cell lines.","method":"Ectopic expression of RhoB-F and RhoB-GG in human cancer cell lines, focus formation assay, soft agar assay, nude mouse xenograft, Western blot for Erk and Akt phosphorylation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple cell lines and in vivo model; single lab but multiple orthogonal methods","pmids":["10770919"],"is_preprint":false},{"year":2002,"finding":"Isoprenylation of RhoB is necessary for its rapid proteasomal degradation; non-isoprenylated RhoB accumulates in the cytosol with increased stability, and simvastatin upregulates RhoB protein by depleting isoprenoid intermediates (geranylgeranyl-pyrophosphate) required for RhoB prenylation and subsequent degradation.","method":"Isoprenylation-deficient RhoB mutant expression, statin treatment with metabolite rescue, protein stability/half-life measurements, Western blot","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mutant analysis and pharmacological rescue, two orthogonal approaches; single lab","pmids":["12384510"],"is_preprint":false},{"year":2003,"finding":"RhoB localizes to endosomes in the perinuclear recycling compartment and is required for catalytic activation of c-Src and its translocation to peripheral membrane structures; RhoB-containing endosomes harbor actin polymerization proteins (e.g. Scar1), and Src controls actin-dependent RhoB endosome movement toward the plasma membrane.","method":"c-Src-GFP live cell imaging, RhoB knockout cells, dominant-negative Rab11 mutant, kinase activity assays, co-localization by confocal microscopy","journal":"Developmental cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic knockout combined with dominant-negative, live imaging, kinase activity assays; multiple orthogonal methods in one rigorous study","pmids":["15572128"],"is_preprint":false},{"year":2003,"finding":"RhoB null endothelial cells undergo apoptosis and fail tube formation; RhoB localizes to the nuclear margin and inside the nucleus where it colocalizes with active phosphorylated Akt; RhoB depletion excludes Akt from the nucleus and decreases total Akt protein in a proteasome-dependent manner, demonstrating RhoB controls Akt nuclear trafficking and endothelial cell survival.","method":"RhoB antisense/dominant-negative, confocal microscopy colocalization, proteasome inhibitor rescue, RhoB null mice retinal vascular development","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple loss-of-function strategies, confocal colocalization, in vivo mouse model, proteasome inhibitor mechanistic rescue","pmids":["14597666"],"is_preprint":false},{"year":2003,"finding":"In Sertoli-germ cell cocultures and in vivo, disruption of adherens junctions induces RhoB, which activates a ROCK1/LIMK1/cofilin signaling pathway (via integrin activation) to regulate Sertoli-germ cell adherens junction dynamics; ROCK inhibitor Y-27632 delays germ cell loss from the seminiferous epithelium.","method":"Immunoprecipitation, immunoblot, phosphorylation assays (phospho-Ser LIMK1), in vivo AF-2364 rat model, ROCK inhibitor treatment, Sertoli-germ cell coculture","journal":"Biology of reproduction","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo evidence, immunoprecipitation and pharmacological inhibition; single lab","pmids":["12606349"],"is_preprint":false},{"year":2003,"finding":"HDAC1 represses RhoB transcription; HDAC inhibitor trapoxin A upregulates RhoB expression via an inverted CCAAT box in the RhoB promoter.","method":"HDAC1 antisense oligonucleotides, HDAC inhibitor (TPX) treatment, promoter reporter assay, RT-PCR","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — antisense loss-of-function and promoter deletion analysis; single lab","pmids":["13679859"],"is_preprint":false},{"year":2004,"finding":"Ras downregulates RhoB expression via a PI3K- and Akt-dependent (but not MEK-dependent) mechanism; pharmacological or genetic blockade of PI3K/Akt upregulates RhoB; ectopic RhoB (but not RhoA) inhibits Ras/PI3K/Akt-induced transformation, migration, and invasion, and induces apoptosis and anoikis.","method":"PI3K/MEK/Akt inhibitors, dominant-negative and constitutively active mutants, RhoB ectopic expression, transformation assay, migration/invasion assay, apoptosis assay","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological and genetic approaches, multiple functional readouts; single lab","pmids":["15169915"],"is_preprint":false},{"year":2004,"finding":"FTI treatment converts RhoB-F (plasma membrane) to RhoB-GG (multivesicular late endosomes), and this prenylation-dependent localization determines function: RhoB-GG reduces EGF receptor sorting to lysosomes and increases receptor recycling to the plasma membrane, without affecting receptor sorting into late endosomes.","method":"FTI treatment, prenylation-specific mutants, subcellular fractionation, ultrastructural analysis (EM), EGFR trafficking assays","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — ultrastructural analysis, prenylation mutants, receptor trafficking assays, multiple orthogonal methods in one study","pmids":["15226397"],"is_preprint":false},{"year":2004,"finding":"H-Ras, N-Ras, K-Ras, EGFR, and ErbB2 (but not v-Src) suppress RhoB promoter transcriptional activity in NIH3T3 and human cancer cells; EGFR/ErbB2 suppression is mediated through Ras; ectopic RhoB (but not RhoA) reverses oncogene-induced transformation and apoptosis resistance.","method":"Promoter reporter assays, ectopic oncogene expression, RhoB overexpression, colony/focus formation, apoptosis assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter assays and functional rescue; single lab with multiple oncogenes tested","pmids":["14647415"],"is_preprint":false},{"year":2004,"finding":"RhoB loss induces a 4–5 carbon isoprene-dependent functional difference: RhoB-GG suppresses Ras-mediated transformation and Akt/NF-κB activation, and induces apoptosis in Ras-transformed NIH-3T3 cells, whereas RhoB-F enhances transformation without inducing apoptosis.","method":"Prenylation-specific RhoB mutants (exclusively farnesylated or geranylgeranylated), anchorage-dependent and -independent growth assays, nude mouse xenograft, Akt/NF-κB activity assays, apoptosis assay","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — exclusive prenylation mutants provide direct mechanistic evidence; multiple assays in single lab","pmids":["15748883"],"is_preprint":false},{"year":2005,"finding":"Palmitoylation of RhoB cysteine 192 (but not cysteine 189) is required for RhoB tumor-suppressive and proapoptotic activities; mutations of C192 or C193 (prenylation site) mislocalize RhoB and block its ability to inhibit tumor growth, induce apoptosis, and suppress gene transcription (TGFβ-RII, p21WAF1, AP-1 promoters); a RhoA(1-180)/RhoB(181-196) chimera retains full RhoB activity.","method":"Site-directed mutagenesis of palmitoylation/prenylation sites, subcellular localization, tumor growth assay (anchorage-dependent/-independent), apoptosis assay, promoter reporter assays, chimeric protein","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — comprehensive mutagenesis of multiple sites with multiple functional readouts; single lab but rigorous mechanistic approach","pmids":["15713677"],"is_preprint":false},{"year":2005,"finding":"UVB rapidly activates GTP-bound RhoB within 5 min (EGFR-independent early step), followed by EGFR-dependent induction of RhoB protein expression; RhoB promotes keratinocyte survival after UVB by sustaining AKT and GSK-3β phosphorylation through maintenance of EGFR expression.","method":"siRNA knockdown of RhoB, RhoB overexpression, GTP-RhoB pulldown assay, EGFR inhibitor, Western blot for Akt/GSK-3β phosphorylation, apoptosis assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function and overexpression with signaling pathway readouts; single lab","pmids":["16278215"],"is_preprint":false},{"year":2005,"finding":"Farnesylated RhoB (RhoB-F), but not RhoB-GG, reduces radiation-induced mitotic cell death and inhibits centrosome overduplication following irradiation via Rho-kinase, increasing G2 arrest after irradiation.","method":"Prenylation-specific RhoB mutants (RhoB-F, RhoB-GG, CAAX-deleted), clonogenic survival assay, centrosome duplication analysis, ROCK inhibitor","journal":"Cell death and differentiation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — prenylation-specific mutants with multiple functional readouts and pharmacological validation; single lab","pmids":["15776002"],"is_preprint":false},{"year":2006,"finding":"FTI and GGTI treatment upregulates RhoB expression at the transcriptional level by causing HDAC1 dissociation, HAT (histone acetyltransferase) association, and histone acetylation of the RhoB promoter.","method":"Chromatin immunoprecipitation (ChIP) for HDAC1 and HAT on RhoB promoter, RT-PCR for RhoB mRNA, actinomycin D block","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP assays directly demonstrating chromatin remodeling at RhoB promoter; single lab","pmids":["16909123"],"is_preprint":false},{"year":2006,"finding":"TRIF-dependent (not MyD88-dependent) LPS signaling in dendritic cells activates RhoB (not RhoA, Cdc42, or Rac1/2) through the GEF GEFH1; activated RhoB colocalizes with MHCII+ lysosomes and is required for LPS-induced MHCII surface expression and CD4+ T cell stimulatory activity.","method":"Dominant-negative RhoB, RhoB RNAi, GEFH1 association with RhoB (co-IP), dominant-negative GEFH1, GTPase activation assays (pulldown), MHCII surface staining, T cell stimulation assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP for GEFH1-RhoB interaction, RNAi and dominant-negative loss-of-function, specific GTPase activation assay, functional T cell readout; multiple orthogonal methods","pmids":["16917499"],"is_preprint":false},{"year":2007,"finding":"RhoB activates NF-κB via ROCK I (not PRK I); the farnesylated form RhoB-F is a potent NF-κB activator whereas RhoB-GG, RhoA, and RhoC show weaker activation; RhoB activation of NF-κB modifies RelA/p65 transactivation domain rather than promoting nuclear translocation; RhoB is required for NF-κB activation by Bcr and TSG101 but not by TNFα or oncogenic Ras.","method":"NF-κB reporter assays, dominant-inhibitory RhoB mutants, siRNA knockdown, ROCK I genetic and pharmacological inhibition, RelA/p65 nuclear translocation assays","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assays with specific inhibitors and siRNA knockdown; single lab, multiple readouts","pmids":["17728102"],"is_preprint":false},{"year":2007,"finding":"RhoB is required for PDGFR-β trafficking to perinuclear late endosomes; in RhoB-null smooth muscle cells, PDGF fails to stimulate proliferation, Akt/ERK phosphorylation, or nuclear translocation of Src/Akt/ERK; restoring RhoB expression in null cells rescues PDGFR-β trafficking and PDGF-induced proliferation.","method":"RhoB knockout mouse-derived cells, PDGF stimulation, subcellular fractionation/confocal microscopy, Western blot for phospho-Akt and phospho-ERK1/2, nuclear fractionation, rescue by RhoB re-expression","journal":"Arteriosclerosis, thrombosis, and vascular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic null cells with rescue experiment, multiple pathway readouts, trafficking localization; rigorous mechanistic study","pmids":["17951322"],"is_preprint":false},{"year":2007,"finding":"RhoB-null macrophages have reduced surface β2 and β3 (but not β1) integrin expression, are more rounded, show reduced adhesion to ICAM-1, and migrate faster on fibronectin but slower on glass; RhoB is not required for podosome assembly.","method":"RhoB-null macrophages, flow cytometry for integrin surface expression, adhesion assay, migration assay, C3 transferase treatment","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic null cells with multiple functional readouts; single lab","pmids":["17692842"],"is_preprint":false},{"year":2007,"finding":"RhoB-containing endosomes are specifically required for Src (but not Fyn) spatial activation and membrane delivery; Fyn requires RhoD-positive endosomes instead, and this specificity is determined by palmitoylation acceptor sites (acylation) in SFK sequences.","method":"siRNA knockdown of RhoB and RhoD, SFK-GFP colocalization by confocal microscopy, kinase activity assays, palmitoylation site mutagenesis in Src/Fyn","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown, mutant analysis, colocalization; single lab","pmids":["17623777"],"is_preprint":false},{"year":2007,"finding":"RhoB plays an essential role in CXCR2 sorting decisions: RhoB GTPase activity oscillation controls whether CXCR2 is sorted to lysosomes for degradation or recycled via Rab11a or Rab4 pathways following CXCL8 stimulation; both dominant-negative and constitutively active RhoB impair CXCR2-mediated chemotaxis.","method":"Dominant-negative (T19N) and activated (Q63L) RhoB mutants, RhoB siRNA, receptor degradation/recycling assays, colocalization with Rab4/Rab11a markers, chemotaxis assay","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple mutant tools and siRNA with receptor trafficking readouts; single lab","pmids":["17405813"],"is_preprint":false},{"year":2008,"finding":"RhoB protein stability is regulated by RhoA-GDP form (not active RhoA) via RhoGDIα: RhoA silencing increases RhoB half-life by making RhoGDIα available to stabilize RhoB; a RhoA mutant (R68E) unable to bind RhoGDIα fails to reverse RhoB upregulation, and forced RhoGDIα expression stabilizes RhoB.","method":"RhoA siRNA, RhoA rescue expression, RhoGDIα knockdown and overexpression, RhoA-R68E mutant (RhoGDIα binding-deficient), protein half-life measurement (cycloheximide chase), Western blot","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic tools (siRNA, mutant, rescue) and biochemical readouts; single lab","pmids":["18524772"],"is_preprint":false},{"year":2008,"finding":"PKC iota (activated downstream of PI3K) represses RhoB mRNA expression; PKC iota depletion increases RhoB protein and induces actin stress fibers and reduced invasion; constitutive RhoB expression recapitulates PKC iota depletion phenotype, and RhoB and PKC iota are mutually antagonistic (RhoB overexpression represses PKC iota phosphorylation at Thr555).","method":"RNAi depletion of PKC iota, pharmacological PKC iota inhibition, gene expression microarray, RhoB ectopic expression, PKC iota phosphorylation Western blot, invasion assay","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi, pharmacological, and overexpression evidence with multiple readouts; single lab","pmids":["18212741"],"is_preprint":false},{"year":2009,"finding":"An eight amino acid C-terminal sequence of RhoB directs its rapid degradation through an endo-lysosomal/multivesicular body (MVB) pathway dependent on protein isoprenylation and palmitoylation, mediated by the ESCRT machinery; RhoB sorting is regulated by late endosome-specific lipid dynamics.","method":"Chimeric protein constructs bearing RhoB C-terminal sequence, confocal microscopy in live primary cells, ultrastructural analysis, ESCRT machinery genetic perturbation, lipid traffic disease cell models","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstitution with chimeric proteins, ultrastructural analysis, mechanistic ESCRT pathway dissection; multiple orthogonal methods","pmids":["19956591"],"is_preprint":false},{"year":2009,"finding":"RhoB loss promotes migration and invasiveness of bronchial cells via specific activation of Akt1 isoform and Rac1; RhoB depletion is critical for motility downstream of K-RasV12 transformation but not for cell proliferation.","method":"RNAi knockdown of RhoB, isoform-specific Akt1 activation measurement, Rac1 activation assay, migration/invasion assay, K-RasV12 transformation model","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi with pathway-specific readouts; single lab","pmids":["19602596"],"is_preprint":false},{"year":2009,"finding":"TGFβ induces RhoB transcription by an MEK/ERK-dependent pathway that recruits Smad3 to a novel non-classical Smad binding element (overlapping with CCAAT box) in the proximal RhoB promoter, in a p53-dependent manner; mutagenesis of this site abolishes Smad-mediated RhoB transactivation; RhoB is required for TGFβ-induced cell migration.","method":"siRNA knockdown, adenoviral gene transfer, MEK/MAPK inhibitors, promoter transactivation assays, Smad3 ChIP/DNA-protein interaction assays, site-directed mutagenesis, dominant-negative RhoB","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — promoter mutagenesis, ChIP/DNA-protein interaction, pharmacological and genetic dissection of pathway; multiple orthogonal methods in one study","pmids":["19890017"],"is_preprint":false},{"year":2010,"finding":"RhoB is required for early-phase LTP in hippocampus; RhoB-null mice show reduced LTP, impaired cofilin phosphorylation in potentiated hippocampus, decreased LIMK phosphorylation, increased dendritic branching, decreased spine number, altered spine morphology (more stubby, longer, wider spines).","method":"RhoB-/- mice, electrophysiology (LTP recording), Western blot for phospho-cofilin and phospho-LIMK, dendritic morphology analysis","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic null mice, electrophysiology, biochemical pathway readouts; single lab","pmids":["20203211"],"is_preprint":false},{"year":2011,"finding":"RhoB links PDGF signaling to cell migration by coordinating RhoB-dependent endosomal trafficking of Cdc42 from perinuclear region to cell periphery, where RhoGEF Vav2 and Rac are recruited to drive formation of circular dorsal and peripheral ruffles necessary for VSMC migration.","method":"RhoB-null vascular smooth muscle cells, GTPase activation assays for Cdc42/Rac, confocal colocalization, Vav2 recruitment assay, circular ruffle formation analysis","journal":"Journal of cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — null cells with trafficking and GTPase activation readouts; single lab","pmids":["21344485"],"is_preprint":false},{"year":2012,"finding":"RhoB-depleted cells are rounded with defects in Rac-mediated spreading and lamellipodia, migrate faster but less persistently, have reduced surface β1 integrin levels and reduced β1 integrin activity in protrusions, and show diffuse substratum contact; RhoB contributes to directional migration by maintaining β1 integrin surface levels to stabilize lamellipodia.","method":"RNAi depletion of RhoB and GEF-H1, chemotaxis assay, surface integrin flow cytometry, integrin activity reporter, confocal microscopy, focal adhesion analysis","journal":"Open biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi with multiple functional and molecular readouts; single lab","pmids":["22724071"],"is_preprint":false},{"year":2012,"finding":"RhoB is required for hypoxia-induced actin stress fiber formation via mDia (actin polymerization) and cooperates with RhoA/Rho kinase (MLC Ser19 phosphorylation) to maximize actomyosin contractility; RhoB is specifically required for HIF-1α stabilization, PDGF- and hypoxia-induced cell proliferation/migration; RhoB deficiency in mice attenuates chronic hypoxia-induced pulmonary hypertension.","method":"Adenoviral constitutively active RhoB, dominant-negative RhoB, farnesyltransferase inhibitor (manumycin), RhoB-/- mice, actin stress fiber imaging, MLC phosphorylation Western blot, HIF-1α stabilization assay, pulmonary hypertension model","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple genetic and pharmacological tools, in vivo mouse model, mechanistic pathway dissection with multiple orthogonal methods","pmids":["22539766"],"is_preprint":false},{"year":2013,"finding":"Nuclear RhoB-GTP controls distinct gene expression programs in blood versus lymphatic endothelial cells by regulating VEZF1-mediated transcription, underlying opposing roles of RhoB in angiogenesis versus lymphangiogenesis.","method":"RhoB null mice, chromatin/VEZF1 transcription assays, RhoB-GTP nuclear localization, primary blood and lymphatic endothelial cell culture, sprouting/proliferation assays, small-molecule VEZF1 inhibitor","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic null model, transcription factor binding assay, pharmacological inhibitor; single lab but multiple orthogonal approaches","pmids":["24280686"],"is_preprint":false},{"year":2013,"finding":"PRK isoforms show highest affinity for RhoB compared to RhoA and RhoC; RhoB uniquely engages both the HR1a and HR1b domains of PRK1 and PRK3 (unlike RhoA and RhoC which interact only via HR1a), and PRK3 displays specific affinity for RhoB dependent on both RhoB C-terminus and PRK3 HR1b domain.","method":"In vitro binding affinity measurements (biochemical), domain deletion and mutagenesis of HR1a/HR1b, thermal stability assays for HR1 domains","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstituted binding measurements with domain mutagenesis; rigorous biochemical characterization","pmids":["24128008"],"is_preprint":false},{"year":2014,"finding":"DNA damage activates a Chk2-HuR-RhoB pathway: DSBs induce RhoB expression via Chk2-dependent stabilization of RhoB mRNA by HuR; RhoB-deficient cells show decreased PP2A activity, fail to dephosphorylate γH2AX after camptothecin removal, and have reduced DSB repair by homologous recombination.","method":"RhoB-/- cells, Chk2 inhibition, HuR knockdown, RNA-binding assay (HuR-RhoB mRNA), PP2A activity assay, γH2AX imaging and Western blot, homologous recombination assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple loss-of-function tools, PP2A activity assay, HR repair assay, mRNA-protein interaction; multiple orthogonal methods in one study","pmids":["24912678"],"is_preprint":false},{"year":2014,"finding":"The E3 ubiquitin ligase Smurf1 promotes RhoB degradation to control its basal abundance; DNA damage activates ATR/Chk1, which phosphorylates Smurf1 to enhance Smurf1 self-degradation, thereby allowing RhoB accumulation and apoptosis; overexpressing Smurf1 or blocking Chk1-dependent Smurf1 self-degradation inhibits apoptosis.","method":"Smurf1 overexpression and knockdown, Chk1 activation assays, Smurf1 phosphorylation Western blot, RhoB protein level measurements, apoptosis assay","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic perturbations and biochemical readouts; single lab","pmids":["25249323"],"is_preprint":false},{"year":2015,"finding":"RhoB directly interacts with and positively regulates the phosphatase PP2A through recruitment of its regulatory subunit B55; this RhoB-PP2A interaction controls Akt1 dephosphorylation and opposes Rac1 activation (via Trio GEF), thereby inhibiting EMT and invasive amoeboid migration in bronchial cells.","method":"Co-immunoprecipitation of RhoB with PP2A-B55 subunit, B55 siRNA knockdown, Akt1 dephosphorylation assay, Rac1 activation assay, 3D matrix invasion assay, siRNA knockdown of Trio","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP for RhoB-PP2A interaction, siRNA rescue experiments, signaling pathway readouts; single lab","pmids":["26148238"],"is_preprint":false},{"year":2015,"finding":"BRAF inhibition induces RHOB expression via the transcription factor c-Jun; RHOB then activates AKT to promote melanoma cell survival; RHOB deficiency causes hypersensitivity to BRAF/MEK inhibitors; AKT inhibition synergizes with vemurafenib in vivo to block RHOB-positive tumor growth.","method":"BRAF/MEK inhibitor treatment, c-Jun knockdown (siRNA), RHOB siRNA, Akt activation Western blot, apoptosis assay, xenograft mouse model","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi and pharmacological pathway dissection, in vivo validation; single lab","pmids":["26098773"],"is_preprint":false},{"year":2016,"finding":"RhoB specifically inhibits endothelial barrier restoration after acute contraction by preventing plasma membrane extension; RhoB colocalizes with Rac1 in endosomes and inhibits Rac1 activity and trafficking to the cell border during barrier recovery; inhibition of endosomal trafficking impairs barrier reformation while Rac1 translocation to plasma membrane accelerates it.","method":"RhoB siRNA knockdown, Rac1 activation assay (pulldown), confocal colocalization of RhoB and Rac1 in endosomes, endosomal trafficking inhibitors, TEER measurement, plasma membrane protrusion analysis","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA, Rac1 activity assays, colocalization, pharmacological inhibition; single lab, multiple orthogonal methods","pmids":["27138256"],"is_preprint":false},{"year":2016,"finding":"RhoB GTPase activity and its redistribution to BTN3A1 (butyrophilin A1) mediates Vγ9Vδ2 TCR activation in response to phosphoantigens in tumor cells; phosphoantigen accumulation promotes RhoB-induced cytoskeletal changes that stabilize BTN3A1 in the membrane, followed by RhoB dissociation from BTN3A1 and a BTN3A1 conformational change recognizable by Vγ9Vδ2 TCR.","method":"Genome-wide screen, RhoB GTPase activity assays, RhoB-BTN3A1 colocalization and co-immunoprecipitation, cytoskeletal analysis, TCR activation assays, BTN3A1 conformational change assay","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — unbiased genome-wide screen followed by mechanistic validation with co-IP, GTPase activity, colocalization, and functional TCR assays; multiple orthogonal methods","pmids":["27210746"],"is_preprint":false},{"year":2017,"finding":"RhoB loss confers resistance to EGFR-TKI (erlotinib) in lung cancer via AKT activation; high RHOB expression prevents erlotinib-induced AKT inhibition in vitro and in vivo; combination of AKT inhibitor with erlotinib induces tumor cell death and regression in RHOB-positive cells.","method":"RHOB siRNA, RHOB overexpression, AKT phosphorylation Western blot, erlotinib treatment in cell lines and EGFRL858R transgenic mouse model, in vivo xenograft with AKT inhibitor combination","journal":"EMBO molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi, overexpression, transgenic mouse model, pharmacological combination; single lab with in vivo validation","pmids":["28003335"],"is_preprint":false},{"year":2017,"finding":"The pseudogene DUXAP8 represses RhoB (and EGR1) transcription by recruiting histone demethylase LSD1 and histone methyltransferase EZH2 to the RhoB promoter, thereby promoting NSCLC cell proliferation, migration, and invasion.","method":"DUXAP8 knockdown/overexpression, LSD1/EZH2 co-IP with DUXAP8, ChIP for LSD1 and EZH2 at RhoB promoter, Western blot and qPCR for RhoB, cell functional assays","journal":"Molecular therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP and ChIP at RhoB promoter; single lab, multiple methods; note this is epigenetic regulation of RhoB expression (not RhoB protein function per se)","pmids":["28131418"],"is_preprint":false},{"year":2018,"finding":"The Cullin-3-Rbx1-KCTD10 E3 ubiquitin ligase complex promotes K63-linked polyubiquitination of RhoB at lysines 162 and 181, targeting RhoB to lysosomes; this ubiquitination controls RhoB subcellular localization, activity, and endothelial barrier integrity by regulating RhoB-mediated endothelial cell contraction.","method":"Co-immunoprecipitation of Cullin-3/Rbx1/KCTD10 with RhoB, ubiquitination site mutagenesis (K162R/K181R), lysosome trafficking assay, endothelial permeability/TEER assay","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — biochemical identification of specific ubiquitination sites by mutagenesis, E3 ligase complex identified by co-IP, functional barrier readout; multiple orthogonal methods in one study","pmids":["29358211"],"is_preprint":false},{"year":2018,"finding":"DNA damage (UV, MMS) leads to ATR/Chk1-mediated phosphorylation of RhoB, which enhances RhoB interaction with TSC2 and promotes RhoB sumoylation by PIAS1; sumoylated RhoB/TSC complex translocates to lysosomes, inhibiting mTORC1 and activating autophagy; sumoylation-resistant RhoB cannot restore autophagy in RhoB-/- cells.","method":"RhoB phosphorylation and sumoylation assays, co-IP of RhoB with TSC2 and PIAS1, lysosomal fractionation, mTORC1 activity assay, autophagy assay (LC3-II), RhoB-/- cells, sumoylation-resistant RhoB mutant rescue","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — PTM identification (phosphorylation, sumoylation) with mutagenesis, co-IP for complex, fractionation for lysosomal translocation, functional mTORC1/autophagy readout; multiple orthogonal methods","pmids":["30297842"],"is_preprint":false},{"year":2018,"finding":"KIF13A-mediated endosomal trafficking regulates RhoB plasma membrane localization: RhoB is internalized via Rab5 vesicles and trafficked to either late endosomes/lysosomes or Rab11-positive recycling endosomes; KIF13A depletion inhibits RhoB plasma membrane localization, membrane blebbing, and 3D amoeboid migration; RhoB drives membrane blebbing and amoeboid migration via downstream ROCK and Myosin II.","method":"KIF13A siRNA, live imaging of RhoB trafficking with Rab5/Rab11 markers, plasma membrane localization quantification, membrane blebbing assay, 3D-collagen migration assay, ROCK/Myosin II inhibitors","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA loss-of-function, live trafficking imaging, pharmacological effector validation, 3D functional assay; multiple orthogonal methods in one rigorous study","pmids":["30049714"],"is_preprint":false},{"year":2019,"finding":"An intrabody (single-domain antibody) that selectively targets the GTP-bound form of RHOB (via CDR3 interaction with the GTP-binding pocket) was identified by cell-based F-box degradation screening; selective degradation of RHOB-GTP (but not total RHOB) impairs genomic instability and cell invasion, demonstrating that only the GTP-bound pool mediates these RHOB functions.","method":"Cell-based F-box/intrabody targeted protein degradation screen, intrabody-RHOB interaction mapping (CDR3/GTP-binding pocket), cell invasion assay, genomic instability assay","journal":"Cell chemical biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — novel targeted degradation screen with functional validation; single lab but mechanistically rigorous","pmids":["31522999"],"is_preprint":false},{"year":1998,"finding":"Prenylated RhoB interacts with the transcription factor DB1 (but not RhoA or H-Ras); prenylated RhoB species are present in the nuclear membrane and intranuclear laminar region; RhoB inhibits DB1-mediated transcriptional activation, suggesting a mechanism by which RhoB regulates transcription via transcription factor sequestration.","method":"Co-immunoprecipitation/binding assay (prenylation-sensitive), subcellular fractionation to nuclear membrane/intranuclear compartment, transcriptional reporter assay","journal":"Cell adhesion and communication","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single co-IP/pulldown, single transcription reporter assay; single lab","pmids":["9865462"],"is_preprint":false},{"year":1997,"finding":"UV-induced rhoB promoter activation requires a 0.17 kb minimal promoter fragment containing TATA and CAAT boxes; overexpression of wild-type Rac or Rho-GDI activates rhoB transcription; wild-type RhoB itself inhibits both basal and UV-stimulated rhoB promoter activity, indicating a negative regulatory feedback; JNK, ERK, and p38 MAP kinase are not required for UV induction of rhoB.","method":"rhoB promoter deletion constructs/reporter assays, MEK inhibitor PD98059, p38 inhibitor SB203580, PI3K inhibitor wortmannin, Rac and Rho-GDI overexpression, run-on transcription analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter deletion analysis with multiple pathway inhibitors and overexpression; single lab, multiple orthogonal approaches","pmids":["9388198"],"is_preprint":false}],"current_model":"RhoB is a short-lived, endosome-localized small GTPase that exists in farnesylated (RhoB-F, plasma membrane/early endosomes) and geranylgeranylated (RhoB-GG, multivesicular late endosomes) forms, undergoes rapid lysosomal degradation directed by its C-terminal sequence via ESCRT/MVB sorting, is stabilized by RhoGDIα and destabilized by Smurf1-mediated ubiquitination (and K63-ubiquitination by Cullin-3-Rbx1-KCTD10), is transcriptionally induced by DNA damage, UV, TGFβ, and hypoxia, and is repressed by Ras/PI3K/Akt signaling and HDAC1-mediated histone deacetylation; mechanistically, RhoB coordinates endosomal trafficking of receptor tyrosine kinases (EGFR, PDGFR-β, CXCR2) and signaling molecules (Src, Akt, Cdc42, Rac1), regulates actin dynamics via the ROCK/LIMK/cofilin axis and mDia-mediated polymerization, promotes DSB repair via a Chk2-HuR-RhoB-PP2A pathway, drives autophagy through ATR/Chk1-phosphorylation-dependent sumoylation and lysosomal recruitment of the TSC complex to inhibit mTORC1, activates NF-κB via ROCK I (preferentially in its farnesylated form), and binds PRK isoforms (with highest affinity through both HR1a and HR1b domains) to regulate downstream signaling and cell transformation suppression."},"narrative":{"mechanistic_narrative":"RHOB is a rapidly turned-over, endosome-associated small GTPase that governs the intracellular trafficking and spatial activation of receptor tyrosine kinases and signaling proteins, coupling these functions to growth suppression, stress responses, and cytoskeletal control [PMID:10508588, PMID:15572128]. Distinct from RhoA, RHOB localizes to the cytosolic face of endocytic vesicles and the perinuclear recycling compartment, where it controls the sorting of cargo such as EGFR, PDGFR-β, and CXCR2 between lysosomal degradation and recycling routes, and is required for the catalytic activation and membrane delivery of c-Src and the trafficking of Cdc42 and Rac1 [PMID:10508588, PMID:17951322, PMID:17405813, PMID:15572128, PMID:21344485]. RHOB exists as farnesylated and geranylgeranylated species whose prenylation state dictates membrane targeting and function: geranylgeranylated RHOB suppresses Ras-mediated transformation, induces p21WAF1 and apoptosis, and mediates the antineoplastic effects of farnesyltransferase inhibitors, with genetic ablation rendering Ras-transformed cells defective in FTI-induced apoptosis [PMID:10022870, PMID:10554025, PMID:10913192, PMID:15748883]. RHOB acts as a tumor suppressor downstream of oncogenic signaling, being transcriptionally repressed by Ras/PI3K/Akt and HDAC1, and induced by DNA damage, UV, TGFβ, and hypoxia [PMID:15169915, PMID:13679859, PMID:19890017, PMID:24912678]; its abundance is set by isoprenylation-dependent endo-lysosomal degradation directed by an eight-residue C-terminal sequence routed through the ESCRT/MVB pathway, by Smurf1- and Cullin-3–Rbx1–KCTD10-mediated ubiquitination, and by RhoGDIα-dependent stabilization [PMID:19956591, PMID:25249323, PMID:29358211, PMID:18524772]. Mechanistically, RHOB drives actin remodeling through the ROCK/LIMK/cofilin and mDia axes, activates NF-κB via ROCK I in its farnesylated form, promotes homologous-recombination DSB repair through a Chk2-HuR-RhoB-PP2A pathway, and triggers autophagy by ATR/Chk1-dependent phosphorylation and PIAS1-mediated sumoylation that recruits the TSC complex to lysosomes to inhibit mTORC1 [PMID:22539766, PMID:17728102, PMID:24912678, PMID:30297842]. RHOB binds PRK isoforms with high affinity through both HR1a and HR1b domains and only its GTP-bound pool mediates genomic instability and invasion [PMID:24128008, PMID:31522999].","teleology":[{"year":1997,"claim":"Established how rhoB transcription is controlled, defining a minimal stress-responsive promoter and a negative autoregulatory loop, framing RhoB as an inducible immediate stress gene.","evidence":"rhoB promoter deletion/reporter assays with MAPK and PI3K inhibitors and Rac/Rho-GDI overexpression","pmids":["9388198"],"confidence":"Medium","gaps":["Did not identify the transcription factors binding the minimal element","Mechanism of RhoB-mediated negative feedback unresolved"]},{"year":1998,"claim":"First linked prenylated RhoB to nuclear transcription factor sequestration, raising the possibility that RhoB regulates transcription directly.","evidence":"Prenylation-sensitive co-IP with transcription factor DB1, nuclear fractionation, reporter assays","pmids":["9865462"],"confidence":"Low","gaps":["Single co-IP and single reporter assay without reciprocal validation","Identity and significance of DB1 target genes not established"]},{"year":1999,"claim":"Defined RhoB's distinguishing endosomal localization and showed it controls EGFR trafficking kinetics via PRK1, separating it functionally from plasma-membrane RhoA.","evidence":"Subcellular imaging, PRK1 binding assays, dominant-active/negative mutants, EGFR trafficking assays","pmids":["10508588"],"confidence":"Medium","gaps":["GTPase cycle regulators on endosomes not identified","Connection between PRK1 binding and trafficking kinetics mechanistically incomplete"]},{"year":1999,"claim":"Demonstrated that the geranylgeranylated RhoB species gained upon FTI treatment is sufficient to revert Ras transformation and induce p21WAF1, mechanistically linking RhoB to FTI action.","evidence":"Ectopic RhoB-GG expression in Ras-transformed and human carcinoma cells, colony/cell-cycle/apoptosis assays, p21WAF1 blots","pmids":["10022870","10554025"],"confidence":"High","gaps":["Why RhoB-GG selectively affects transformed but not normal cells unresolved","Direct effectors downstream of RhoB-GG growth suppression not defined"]},{"year":2000,"claim":"Provided genetic proof via rhoB-null cells that RhoB is a crucial mediator of FTI-induced apoptosis and antitumor responses, and showed both prenyl forms suppress growth and Akt/Erk signaling.","evidence":"rhoB gene knockout with E1A+H-Ras transformation, FTI treatment, apoptosis and xenograft assays, Akt/Erk blots","pmids":["10913192","10770919"],"confidence":"High","gaps":["Molecular target by which RhoB triggers apoptosis not identified","How RhoB inhibits Akt/Erk activation mechanistically unresolved"]},{"year":2002,"claim":"Resolved the basis of RhoB's short half-life by showing isoprenylation is required for its rapid proteasomal degradation, explaining statin-mediated RhoB upregulation.","evidence":"Isoprenylation-deficient mutants, statin treatment with metabolite rescue, protein half-life measurements","pmids":["12384510"],"confidence":"Medium","gaps":["The degradation machinery recognizing prenylated RhoB not yet identified","Reconciliation with later endo-lysosomal degradation route incomplete"]},{"year":2003,"claim":"Connected RhoB endosomes to spatial control of signaling kinases and survival, showing RhoB is required for c-Src activation, Akt nuclear trafficking, and endothelial survival.","evidence":"RhoB knockout cells, live c-Src/Akt imaging, kinase activity assays, proteasome inhibitor rescue, RhoB-null mice","pmids":["15572128","14597666"],"confidence":"High","gaps":["How RhoB couples endosome movement to kinase activation mechanistically open","Direct RhoB effectors mediating Akt nuclear import not identified"]},{"year":2003,"claim":"Identified HDAC1 as a transcriptional repressor of RhoB acting through an inverted CCAAT box, and showed RhoB drives a ROCK1/LIMK1/cofilin pathway in junction dynamics.","evidence":"HDAC1 antisense, HDAC inhibitor and promoter reporter assays; immunoprecipitation, phospho-LIMK1 assays, ROCK inhibition in Sertoli-germ cell models","pmids":["13679859","12606349"],"confidence":"Medium","gaps":["Factors recruiting HDAC1 to the RhoB promoter not defined","Direct GEF activating RhoB at junctions unidentified"]},{"year":2004,"claim":"Established that Ras represses RhoB via PI3K/Akt and that prenylation form determines opposing functions, with RhoB-GG suppressing and RhoB-F enhancing transformation.","evidence":"PI3K/Akt/MEK inhibitors, prenylation-specific mutants, promoter reporter assays, transformation/apoptosis readouts, EGFR/ErbB2/Ras oncogene panel","pmids":["15169915","14647415","15748883","15226397"],"confidence":"Medium","gaps":["Molecular determinant of opposite RhoB-F vs RhoB-GG outputs unresolved","Link between prenyl-defined endosomal localization and transcriptional suppression incomplete"]},{"year":2005,"claim":"Defined the C-terminal lipid modifications (palmitoylation of Cys192 and prenylation) as determinants of RhoB localization and tumor-suppressive/proapoptotic activity, and dissected prenyl-form-specific radiation and UVB responses.","evidence":"Site-directed mutagenesis, RhoA/RhoB chimera, promoter and apoptosis assays; GTP-RhoB pulldown, EGFR inhibitor, clonogenic and centrosome assays","pmids":["15713677","16278215","15776002"],"confidence":"High","gaps":["Palmitoyltransferase responsible for Cys192 modification not identified","How localization translates to transcriptional suppression mechanistically open"]},{"year":2006,"claim":"Showed FTI/GGTI upregulate RhoB transcriptionally via chromatin remodeling (HDAC1 dissociation, HAT recruitment, histone acetylation) and that LPS-TRIF signaling activates RhoB through GEF-H1 to drive MHCII surface expression.","evidence":"ChIP for HDAC1/HAT on RhoB promoter, RT-PCR; dominant-negative/RNAi RhoB, GEF-H1 co-IP, GTPase pulldown, MHCII and T cell assays","pmids":["16909123","16917499"],"confidence":"Medium","gaps":["Signal connecting prenylation inhibition to promoter chromatin state unresolved","How RhoB directs MHCII+ lysosome trafficking mechanistically incomplete"]},{"year":2007,"claim":"Expanded RhoB's trafficking role across PDGFR-β, CXCR2, and SFK cargoes, established ROCK I as the NF-κB-activating effector of farnesylated RhoB, and defined integrin-dependent migration phenotypes.","evidence":"RhoB-null cells with rescue, receptor sorting/recycling assays, SFK colocalization and kinase assays, NF-κB reporters with ROCK I inhibition, integrin flow cytometry and migration assays","pmids":["17951322","17405813","17623777","17728102","17692842"],"confidence":"High","gaps":["How RhoB GTPase oscillation directs sorting decisions mechanistically unresolved","Mechanism by which RhoB-F selects ROCK I over PRK I for NF-κB not defined"]},{"year":2008,"claim":"Identified RhoGDIα, made available by RhoA-GDP, as a stabilizer of RhoB protein, and PKC iota as a PI3K-driven repressor of RhoB, defining mutually antagonistic regulation.","evidence":"RhoA/RhoGDIα siRNA, rescue and binding-deficient mutants, cycloheximide chase; PKC iota RNAi/inhibition, microarray, invasion assays","pmids":["18524772","18212741"],"confidence":"Medium","gaps":["Structural basis of RhoGDIα-RhoB stabilization not defined","Direct transcriptional effectors of PKC iota repression unidentified"]},{"year":2009,"claim":"Defined the C-terminal eight-residue ESCRT/MVB degradation signal, showed RhoB loss enables Akt1/Rac1-driven invasion, and revealed RhoB's role in synaptic plasticity via cofilin signaling.","evidence":"Chimeric C-terminal constructs, ultrastructure, ESCRT perturbation; RhoB RNAi with isoform-specific Akt1/Rac1 assays; RhoB-null mice LTP and dendritic morphology","pmids":["19956591","19602596","20203211"],"confidence":"High","gaps":["Adaptors linking the C-terminal signal to ESCRT recognition not identified","How loss of RhoB selectively activates Akt1 isoform unresolved"]},{"year":2009,"claim":"Showed TGFβ induces RhoB transcription via MEK/ERK-dependent Smad3 recruitment to a non-classical element, integrating RhoB into TGFβ-driven migration.","evidence":"Promoter mutagenesis, Smad3 ChIP/DNA-protein assays, MEK inhibitors, dominant-negative RhoB, migration assays","pmids":["19890017"],"confidence":"High","gaps":["p53 requirement mechanism at the promoter not fully defined","Downstream RhoB effectors for TGFβ migration unresolved"]},{"year":2011,"claim":"Established that RhoB coordinates endosomal trafficking of Cdc42 to the periphery, recruiting Vav2/Rac to drive ruffle formation and VSMC migration, integrating its cargo-sorting role with motility.","evidence":"RhoB-null VSMCs, Cdc42/Rac GTPase activation assays, Vav2 recruitment and ruffle analysis, confocal colocalization","pmids":["21344485"],"confidence":"Medium","gaps":["How RhoB selects Cdc42 as endosomal cargo unresolved","Direct RhoB effector mediating Cdc42 transport not identified"]},{"year":2012,"claim":"Connected RhoB to hypoxia responses, showing it is required for HIF-1α stabilization and cooperates with mDia and RhoA/ROCK for actomyosin contractility, with in vivo consequences for pulmonary hypertension; refined integrin-dependent directional migration.","evidence":"Constitutively active/dominant-negative RhoB, FTI, RhoB-null mice, stress fiber and MLC phosphorylation assays, pulmonary hypertension model; RhoB/GEF-H1 RNAi with integrin and migration readouts","pmids":["22539766","22724071"],"confidence":"High","gaps":["Mechanism by which RhoB stabilizes HIF-1α not defined","How RhoB maintains β1 integrin surface levels mechanistically open"]},{"year":2013,"claim":"Identified nuclear RhoB-GTP as a regulator of VEZF1-dependent transcription programs distinguishing blood from lymphatic endothelium, and mapped PRK domain selectivity, showing RhoB uniquely engages both HR1a and HR1b.","evidence":"RhoB-null mice, VEZF1 transcription assays, nuclear RhoB-GTP localization; in vitro PRK binding affinity and HR1a/HR1b domain mutagenesis","pmids":["24280686","24128008"],"confidence":"High","gaps":["How nuclear RhoB-GTP is generated and regulated unresolved","Functional consequence of dual HR1a/HR1b PRK engagement in cells not established"]},{"year":2014,"claim":"Defined a DNA damage axis in which Chk2-HuR stabilizes RhoB mRNA to promote PP2A-dependent γH2AX dephosphorylation and homologous-recombination repair, while ATR/Chk1-driven Smurf1 self-degradation allows RhoB accumulation and apoptosis.","evidence":"RhoB-null cells, Chk2 inhibition, HuR knockdown and RNA-binding assays, PP2A activity and HR assays; Smurf1 overexpression/knockdown, Chk1 and phosphorylation assays, apoptosis readout","pmids":["24912678","25249323"],"confidence":"High","gaps":["How RhoB activates PP2A toward γH2AX mechanistically incomplete","Substrate specificity of Smurf1 toward RhoB not structurally defined"]},{"year":2015,"claim":"Established RhoB as a direct positive regulator of PP2A via the B55 subunit controlling Akt1 dephosphorylation and Rac1 antagonism, and identified c-Jun-driven RHOB induction promoting AKT-dependent melanoma survival under BRAF inhibition.","evidence":"RhoB-PP2A-B55 co-IP, B55/Trio siRNA, Akt1/Rac1 activity and 3D invasion assays; BRAF/MEK inhibitors, c-Jun and RHOB siRNA, AKT blots, xenografts","pmids":["26148238","26098773"],"confidence":"Medium","gaps":["Structural basis of RhoB-PP2A-B55 recruitment not defined","Context-dependence of RhoB promoting vs opposing AKT unresolved"]},{"year":2016,"claim":"Revealed RhoB-dependent endosomal sequestration of Rac1 in endothelial barrier recovery and a phosphoantigen-sensing role at BTN3A1 for Vγ9Vδ2 TCR activation, broadening RhoB's spatial-regulatory repertoire.","evidence":"RhoB siRNA, Rac1 activity assays, endosomal colocalization and trafficking inhibitors, TEER; genome-wide screen, RhoB-BTN3A1 co-IP/colocalization, TCR activation and conformation assays","pmids":["27138256","27210746"],"confidence":"High","gaps":["How RhoB GTPase cycling times BTN3A1 stabilization and release unresolved","Mechanism of RhoB-mediated Rac1 retention in endosomes not defined"]},{"year":2017,"claim":"Identified RHOB as a determinant of EGFR-TKI sensitivity through AKT regulation, and uncovered pseudogene DUXAP8-mediated epigenetic silencing of RhoB via LSD1/EZH2 recruitment.","evidence":"RHOB siRNA/overexpression, AKT blots, erlotinib in cells and EGFRL858R mice, AKT-inhibitor combination; DUXAP8 perturbation, LSD1/EZH2 co-IP and ChIP at RhoB promoter, functional assays","pmids":["28003335","28131418"],"confidence":"Medium","gaps":["How RHOB level dictates AKT response to TKI mechanistically incomplete","Whether DUXAP8 silencing operates broadly across cancers unresolved"]},{"year":2018,"claim":"Defined post-translational control of RhoB localization and function: Cullin-3–Rbx1–KCTD10 K63-ubiquitination targets RhoB to lysosomes, KIF13A-mediated endosomal trafficking sets plasma-membrane RhoB driving blebbing/amoeboid migration, and ATR/Chk1 phosphorylation plus PIAS1 sumoylation route a RhoB-TSC complex to lysosomes to inhibit mTORC1 and activate autophagy.","evidence":"Cullin-3/Rbx1/KCTD10 co-IP and K162R/K181R mutagenesis with TEER; KIF13A siRNA, live trafficking imaging, ROCK/Myosin II inhibitors, 3D migration; RhoB phospho/sumoylation assays, TSC2/PIAS1 co-IP, lysosomal fractionation, mTORC1/autophagy readouts","pmids":["29358211","30049714","30297842"],"confidence":"High","gaps":["How distinct ubiquitin/sumoylation marks are selected for different fates unresolved","Coordination between trafficking, mTORC1 inhibition, and degradation pathways incomplete"]},{"year":2019,"claim":"Demonstrated with a GTP-state-selective intrabody degrader that only the GTP-bound RHOB pool mediates genomic instability and invasion, distinguishing active-form function from total protein.","evidence":"Cell-based F-box/intrabody targeted degradation screen, CDR3/GTP-pocket interaction mapping, invasion and genomic instability assays","pmids":["31522999"],"confidence":"Medium","gaps":["GEFs/GAPs setting the GTP-bound RHOB pool in these contexts not identified","Whether GTP-selective targeting is therapeutically tractable unestablished"]},{"year":null,"claim":"How RhoB integrates its many prenyl-form-, ubiquitin-, sumoyl-, and phosphorylation-dependent states with specific GEF/GAP regulators to select among trafficking, transcriptional, repair, autophagy, and contractility outputs in a given cell remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model linking PTM-defined RhoB states to specific effector choices","Endosomal GEFs/GAPs controlling the RhoB GTPase cycle largely unidentified","Structural basis for prenyl-form-specific effector selection (ROCK I vs PRK) lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003924","term_label":"GTPase activity","supporting_discovery_ids":[0,15,18,23,40,46]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[6,7,35,37]},{"term_id":"GO:0140313","term_label":"molecular sequestering activity","supporting_discovery_ids":[47,44]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[0,6,11,23,30,39,45]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[26,43,44,11]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[11,45,40]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[7,33,47]}],"pathway":[{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0,11,20,23,30,45]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[6,26,43,45]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[10,15,19,38,41]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[35]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[44]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[3,4,7,36]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[9,17,28,33,42,48]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[1,2,3,38,41]}],"complexes":["RhoB-PP2A (B55) complex","Cullin-3–Rbx1–KCTD10 E3 ligase complex","RhoB-TSC complex"],"partners":["PRK1","PP2A","SMURF1","KCTD10","TSC2","PIAS1","RHOGDIΑ","GEF-H1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P62745","full_name":"Rho-related GTP-binding protein RhoB","aliases":["Rho cDNA clone 6","h6"],"length_aa":196,"mass_kda":22.1,"function":"Mediates apoptosis in neoplastically transformed cells after DNA damage. Not essential for development but affects cell adhesion and growth factor signaling in transformed cells. Plays a negative role in tumorigenesis as deletion causes tumor formation. Involved in intracellular protein trafficking of a number of proteins. Targets PKN1 to endosomes and is involved in trafficking of the EGF receptor from late endosomes to lysosomes. Also required for stability and nuclear trafficking of AKT1/AKT which promotes endothelial cell survival during vascular development. Serves as a microtubule-dependent signal that is required for the myosin contractile ring formation during cell cycle cytokinesis. Required for genotoxic stress-induced cell death in breast cancer cells","subcellular_location":"Late endosome membrane; Cell membrane; Nucleus; Cleavage furrow","url":"https://www.uniprot.org/uniprotkb/P62745/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RHOB","classification":"Not Classified","n_dependent_lines":5,"n_total_lines":1208,"dependency_fraction":0.0041390728476821195},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000143878","cell_line_id":"CID000585","localizations":[{"compartment":"membrane","grade":3},{"compartment":"vesicles","grade":3}],"interactors":[{"gene":"ANKRD13A","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000585","total_profiled":1310},"omim":[{"mim_id":"617043","title":"RHO GUANINE NUCLEOTIDE EXCHANGE FACTOR 17; ARHGEF17","url":"https://www.omim.org/entry/617043"},{"mim_id":"612115","title":"RHO GUANINE NUCLEOTIDE EXCHANGE FACTOR 3; ARHGEF3","url":"https://www.omim.org/entry/612115"},{"mim_id":"607560","title":"RHO GUANINE NUCLEOTIDE EXCHANGE FACTOR 2; ARHGEF2","url":"https://www.omim.org/entry/607560"},{"mim_id":"602924","title":"RHO FAMILY GTPase 3; RND3","url":"https://www.omim.org/entry/602924"},{"mim_id":"600046","title":"ATP-BINDING CASSETTE, SUBFAMILY A, MEMBER 1; ABCA1","url":"https://www.omim.org/entry/600046"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"blood vessel","ntpm":1648.0}],"url":"https://www.proteinatlas.org/search/RHOB"},"hgnc":{"alias_symbol":["RHOH6","MST081"],"prev_symbol":["ARH6","ARHB"]},"alphafold":{"accession":"P62745","domains":[{"cath_id":"3.40.50.300","chopping":"3-179","consensus_level":"medium","plddt":96.9442,"start":3,"end":179}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P62745","model_url":"https://alphafold.ebi.ac.uk/files/AF-P62745-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P62745-F1-predicted_aligned_error_v6.png","plddt_mean":92.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RHOB","jax_strain_url":"https://www.jax.org/strain/search?query=RHOB"},"sequence":{"accession":"P62745","fasta_url":"https://rest.uniprot.org/uniprotkb/P62745.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P62745/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P62745"}},"corpus_meta":[{"pmid":"15501444","id":"PMC_15501444","title":"Why three Rho proteins? 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Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/17547697","citation_count":29,"is_preprint":false},{"pmid":"29474434","id":"PMC_29474434","title":"RETRACTED: MicroRNA-19a and microRNA-19b promote the malignancy of clear cell renal cell carcinoma through targeting the tumor suppressor RhoB.","date":"2018","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/29474434","citation_count":29,"is_preprint":false},{"pmid":"28003335","id":"PMC_28003335","title":"The RAS-related GTPase RHOB confers resistance to EGFR-tyrosine kinase inhibitors in non-small-cell lung cancer via an AKT-dependent mechanism.","date":"2017","source":"EMBO molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28003335","citation_count":29,"is_preprint":false},{"pmid":"29702193","id":"PMC_29702193","title":"miR-19a-mediated downregulation of RhoB inhibits the dephosphorylation of AKT1 and induces osteosarcoma cell metastasis.","date":"2018","source":"Cancer letters","url":"https://pubmed.ncbi.nlm.nih.gov/29702193","citation_count":28,"is_preprint":false},{"pmid":"29500478","id":"PMC_29500478","title":"Transcriptional and post-transcriptional regulation of the genes encoding the small GTPases RhoA, RhoB, and RhoC: implications for the pathogenesis of human diseases.","date":"2018","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/29500478","citation_count":27,"is_preprint":false},{"pmid":"23339407","id":"PMC_23339407","title":"RhoB modifies estrogen responses in breast cancer cells by influencing expression of the estrogen receptor.","date":"2013","source":"Breast cancer research : BCR","url":"https://pubmed.ncbi.nlm.nih.gov/23339407","citation_count":27,"is_preprint":false},{"pmid":"10906464","id":"PMC_10906464","title":"RhoB is expressed in migrating neural crest and endocardial cushions of the developing mouse embryo.","date":"2000","source":"Mechanisms of development","url":"https://pubmed.ncbi.nlm.nih.gov/10906464","citation_count":27,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":48208,"output_tokens":12770,"usd":0.168087,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":24313,"output_tokens":8758,"usd":0.170258,"stage2_stop_reason":"end_turn"},"total_usd":0.338345,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"RhoB localizes exclusively to the cytosolic face of endocytic vesicles (not the plasma membrane like RhoA) and acts through the RhoA effector PRK1, which RhoB binds and targets to the endosomal compartment, to regulate the kinetics of EGF receptor intracellular trafficking.\",\n      \"method\": \"Subcellular localization studies, co-immunoprecipitation/binding assays, dominant-active/dominant-negative mutant expression, receptor trafficking assays\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — localization by imaging, binding interaction demonstrated, functional consequence on EGFR trafficking shown; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"10508588\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"FTI treatment causes loss of farnesylated RhoB and gain of geranylgeranylated RhoB (RhoB-GG); ectopic RhoB-GG in Ras-transformed cells induces phenotypic reversion, growth inhibition, and p21WAF1 activation, demonstrating that gain of RhoB-GG is sufficient to mediate FTI-induced cell growth inhibition in transformed but not normal cells.\",\n      \"method\": \"Ectopic expression of RhoB-GG mutant in Ras-transformed cells, colony assay, cell growth assay, Western blot for p21WAF1\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal functional assays, replicated across multiple labs in subsequent papers\",\n      \"pmids\": [\"10022870\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Geranylgeranylated RhoB (RhoB-GG) suppresses human tumor cell proliferation by inducing p21WAF1 in a p53-dependent manner, and promotes apoptosis and G2-M accumulation in a p53-independent manner in human carcinoma cells.\",\n      \"method\": \"Ectopic expression of RhoB-GG in FTI-sensitive vs. resistant human carcinoma cells, cell cycle analysis, apoptosis assay, p21WAF1 Western blot in p53-null cells\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple human cell lines tested, multiple readouts; single lab\",\n      \"pmids\": [\"10554025\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RhoB-null fibroblasts (rhoB-/-) transformed by E1A+H-Ras are defective in FTI-induced apoptosis in vitro and in vivo, and show impaired antitumor responses in xenograft assays, providing genetic proof that RhoB-GG is a crucial mediator of FTI antineoplastic effects.\",\n      \"method\": \"Homozygous rhoB gene deletion, E1A+H-Ras cotransformation, FTI treatment, apoptosis assay in vitro, xenograft tumor assay in vivo\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout model with multiple functional readouts in vitro and in vivo; rigorous loss-of-function approach\",\n      \"pmids\": [\"10913192\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Both farnesylated (RhoB-F) and geranylgeranylated (RhoB-GG) forms of RhoB inhibit anchorage-dependent and -independent growth, induce apoptosis, inhibit constitutive Erk and IGF-1-stimulated Akt activation, and suppress tumor growth in nude mice in several human cancer cell lines.\",\n      \"method\": \"Ectopic expression of RhoB-F and RhoB-GG in human cancer cell lines, focus formation assay, soft agar assay, nude mouse xenograft, Western blot for Erk and Akt phosphorylation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple cell lines and in vivo model; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"10770919\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Isoprenylation of RhoB is necessary for its rapid proteasomal degradation; non-isoprenylated RhoB accumulates in the cytosol with increased stability, and simvastatin upregulates RhoB protein by depleting isoprenoid intermediates (geranylgeranyl-pyrophosphate) required for RhoB prenylation and subsequent degradation.\",\n      \"method\": \"Isoprenylation-deficient RhoB mutant expression, statin treatment with metabolite rescue, protein stability/half-life measurements, Western blot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mutant analysis and pharmacological rescue, two orthogonal approaches; single lab\",\n      \"pmids\": [\"12384510\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"RhoB localizes to endosomes in the perinuclear recycling compartment and is required for catalytic activation of c-Src and its translocation to peripheral membrane structures; RhoB-containing endosomes harbor actin polymerization proteins (e.g. Scar1), and Src controls actin-dependent RhoB endosome movement toward the plasma membrane.\",\n      \"method\": \"c-Src-GFP live cell imaging, RhoB knockout cells, dominant-negative Rab11 mutant, kinase activity assays, co-localization by confocal microscopy\",\n      \"journal\": \"Developmental cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic knockout combined with dominant-negative, live imaging, kinase activity assays; multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"15572128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"RhoB null endothelial cells undergo apoptosis and fail tube formation; RhoB localizes to the nuclear margin and inside the nucleus where it colocalizes with active phosphorylated Akt; RhoB depletion excludes Akt from the nucleus and decreases total Akt protein in a proteasome-dependent manner, demonstrating RhoB controls Akt nuclear trafficking and endothelial cell survival.\",\n      \"method\": \"RhoB antisense/dominant-negative, confocal microscopy colocalization, proteasome inhibitor rescue, RhoB null mice retinal vascular development\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple loss-of-function strategies, confocal colocalization, in vivo mouse model, proteasome inhibitor mechanistic rescue\",\n      \"pmids\": [\"14597666\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"In Sertoli-germ cell cocultures and in vivo, disruption of adherens junctions induces RhoB, which activates a ROCK1/LIMK1/cofilin signaling pathway (via integrin activation) to regulate Sertoli-germ cell adherens junction dynamics; ROCK inhibitor Y-27632 delays germ cell loss from the seminiferous epithelium.\",\n      \"method\": \"Immunoprecipitation, immunoblot, phosphorylation assays (phospho-Ser LIMK1), in vivo AF-2364 rat model, ROCK inhibitor treatment, Sertoli-germ cell coculture\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo evidence, immunoprecipitation and pharmacological inhibition; single lab\",\n      \"pmids\": [\"12606349\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"HDAC1 represses RhoB transcription; HDAC inhibitor trapoxin A upregulates RhoB expression via an inverted CCAAT box in the RhoB promoter.\",\n      \"method\": \"HDAC1 antisense oligonucleotides, HDAC inhibitor (TPX) treatment, promoter reporter assay, RT-PCR\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — antisense loss-of-function and promoter deletion analysis; single lab\",\n      \"pmids\": [\"13679859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Ras downregulates RhoB expression via a PI3K- and Akt-dependent (but not MEK-dependent) mechanism; pharmacological or genetic blockade of PI3K/Akt upregulates RhoB; ectopic RhoB (but not RhoA) inhibits Ras/PI3K/Akt-induced transformation, migration, and invasion, and induces apoptosis and anoikis.\",\n      \"method\": \"PI3K/MEK/Akt inhibitors, dominant-negative and constitutively active mutants, RhoB ectopic expression, transformation assay, migration/invasion assay, apoptosis assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological and genetic approaches, multiple functional readouts; single lab\",\n      \"pmids\": [\"15169915\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"FTI treatment converts RhoB-F (plasma membrane) to RhoB-GG (multivesicular late endosomes), and this prenylation-dependent localization determines function: RhoB-GG reduces EGF receptor sorting to lysosomes and increases receptor recycling to the plasma membrane, without affecting receptor sorting into late endosomes.\",\n      \"method\": \"FTI treatment, prenylation-specific mutants, subcellular fractionation, ultrastructural analysis (EM), EGFR trafficking assays\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — ultrastructural analysis, prenylation mutants, receptor trafficking assays, multiple orthogonal methods in one study\",\n      \"pmids\": [\"15226397\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"H-Ras, N-Ras, K-Ras, EGFR, and ErbB2 (but not v-Src) suppress RhoB promoter transcriptional activity in NIH3T3 and human cancer cells; EGFR/ErbB2 suppression is mediated through Ras; ectopic RhoB (but not RhoA) reverses oncogene-induced transformation and apoptosis resistance.\",\n      \"method\": \"Promoter reporter assays, ectopic oncogene expression, RhoB overexpression, colony/focus formation, apoptosis assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter assays and functional rescue; single lab with multiple oncogenes tested\",\n      \"pmids\": [\"14647415\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"RhoB loss induces a 4–5 carbon isoprene-dependent functional difference: RhoB-GG suppresses Ras-mediated transformation and Akt/NF-κB activation, and induces apoptosis in Ras-transformed NIH-3T3 cells, whereas RhoB-F enhances transformation without inducing apoptosis.\",\n      \"method\": \"Prenylation-specific RhoB mutants (exclusively farnesylated or geranylgeranylated), anchorage-dependent and -independent growth assays, nude mouse xenograft, Akt/NF-κB activity assays, apoptosis assay\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — exclusive prenylation mutants provide direct mechanistic evidence; multiple assays in single lab\",\n      \"pmids\": [\"15748883\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Palmitoylation of RhoB cysteine 192 (but not cysteine 189) is required for RhoB tumor-suppressive and proapoptotic activities; mutations of C192 or C193 (prenylation site) mislocalize RhoB and block its ability to inhibit tumor growth, induce apoptosis, and suppress gene transcription (TGFβ-RII, p21WAF1, AP-1 promoters); a RhoA(1-180)/RhoB(181-196) chimera retains full RhoB activity.\",\n      \"method\": \"Site-directed mutagenesis of palmitoylation/prenylation sites, subcellular localization, tumor growth assay (anchorage-dependent/-independent), apoptosis assay, promoter reporter assays, chimeric protein\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — comprehensive mutagenesis of multiple sites with multiple functional readouts; single lab but rigorous mechanistic approach\",\n      \"pmids\": [\"15713677\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"UVB rapidly activates GTP-bound RhoB within 5 min (EGFR-independent early step), followed by EGFR-dependent induction of RhoB protein expression; RhoB promotes keratinocyte survival after UVB by sustaining AKT and GSK-3β phosphorylation through maintenance of EGFR expression.\",\n      \"method\": \"siRNA knockdown of RhoB, RhoB overexpression, GTP-RhoB pulldown assay, EGFR inhibitor, Western blot for Akt/GSK-3β phosphorylation, apoptosis assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function and overexpression with signaling pathway readouts; single lab\",\n      \"pmids\": [\"16278215\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Farnesylated RhoB (RhoB-F), but not RhoB-GG, reduces radiation-induced mitotic cell death and inhibits centrosome overduplication following irradiation via Rho-kinase, increasing G2 arrest after irradiation.\",\n      \"method\": \"Prenylation-specific RhoB mutants (RhoB-F, RhoB-GG, CAAX-deleted), clonogenic survival assay, centrosome duplication analysis, ROCK inhibitor\",\n      \"journal\": \"Cell death and differentiation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — prenylation-specific mutants with multiple functional readouts and pharmacological validation; single lab\",\n      \"pmids\": [\"15776002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"FTI and GGTI treatment upregulates RhoB expression at the transcriptional level by causing HDAC1 dissociation, HAT (histone acetyltransferase) association, and histone acetylation of the RhoB promoter.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP) for HDAC1 and HAT on RhoB promoter, RT-PCR for RhoB mRNA, actinomycin D block\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP assays directly demonstrating chromatin remodeling at RhoB promoter; single lab\",\n      \"pmids\": [\"16909123\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"TRIF-dependent (not MyD88-dependent) LPS signaling in dendritic cells activates RhoB (not RhoA, Cdc42, or Rac1/2) through the GEF GEFH1; activated RhoB colocalizes with MHCII+ lysosomes and is required for LPS-induced MHCII surface expression and CD4+ T cell stimulatory activity.\",\n      \"method\": \"Dominant-negative RhoB, RhoB RNAi, GEFH1 association with RhoB (co-IP), dominant-negative GEFH1, GTPase activation assays (pulldown), MHCII surface staining, T cell stimulation assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP for GEFH1-RhoB interaction, RNAi and dominant-negative loss-of-function, specific GTPase activation assay, functional T cell readout; multiple orthogonal methods\",\n      \"pmids\": [\"16917499\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"RhoB activates NF-κB via ROCK I (not PRK I); the farnesylated form RhoB-F is a potent NF-κB activator whereas RhoB-GG, RhoA, and RhoC show weaker activation; RhoB activation of NF-κB modifies RelA/p65 transactivation domain rather than promoting nuclear translocation; RhoB is required for NF-κB activation by Bcr and TSG101 but not by TNFα or oncogenic Ras.\",\n      \"method\": \"NF-κB reporter assays, dominant-inhibitory RhoB mutants, siRNA knockdown, ROCK I genetic and pharmacological inhibition, RelA/p65 nuclear translocation assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assays with specific inhibitors and siRNA knockdown; single lab, multiple readouts\",\n      \"pmids\": [\"17728102\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"RhoB is required for PDGFR-β trafficking to perinuclear late endosomes; in RhoB-null smooth muscle cells, PDGF fails to stimulate proliferation, Akt/ERK phosphorylation, or nuclear translocation of Src/Akt/ERK; restoring RhoB expression in null cells rescues PDGFR-β trafficking and PDGF-induced proliferation.\",\n      \"method\": \"RhoB knockout mouse-derived cells, PDGF stimulation, subcellular fractionation/confocal microscopy, Western blot for phospho-Akt and phospho-ERK1/2, nuclear fractionation, rescue by RhoB re-expression\",\n      \"journal\": \"Arteriosclerosis, thrombosis, and vascular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic null cells with rescue experiment, multiple pathway readouts, trafficking localization; rigorous mechanistic study\",\n      \"pmids\": [\"17951322\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"RhoB-null macrophages have reduced surface β2 and β3 (but not β1) integrin expression, are more rounded, show reduced adhesion to ICAM-1, and migrate faster on fibronectin but slower on glass; RhoB is not required for podosome assembly.\",\n      \"method\": \"RhoB-null macrophages, flow cytometry for integrin surface expression, adhesion assay, migration assay, C3 transferase treatment\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic null cells with multiple functional readouts; single lab\",\n      \"pmids\": [\"17692842\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"RhoB-containing endosomes are specifically required for Src (but not Fyn) spatial activation and membrane delivery; Fyn requires RhoD-positive endosomes instead, and this specificity is determined by palmitoylation acceptor sites (acylation) in SFK sequences.\",\n      \"method\": \"siRNA knockdown of RhoB and RhoD, SFK-GFP colocalization by confocal microscopy, kinase activity assays, palmitoylation site mutagenesis in Src/Fyn\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown, mutant analysis, colocalization; single lab\",\n      \"pmids\": [\"17623777\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"RhoB plays an essential role in CXCR2 sorting decisions: RhoB GTPase activity oscillation controls whether CXCR2 is sorted to lysosomes for degradation or recycled via Rab11a or Rab4 pathways following CXCL8 stimulation; both dominant-negative and constitutively active RhoB impair CXCR2-mediated chemotaxis.\",\n      \"method\": \"Dominant-negative (T19N) and activated (Q63L) RhoB mutants, RhoB siRNA, receptor degradation/recycling assays, colocalization with Rab4/Rab11a markers, chemotaxis assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple mutant tools and siRNA with receptor trafficking readouts; single lab\",\n      \"pmids\": [\"17405813\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"RhoB protein stability is regulated by RhoA-GDP form (not active RhoA) via RhoGDIα: RhoA silencing increases RhoB half-life by making RhoGDIα available to stabilize RhoB; a RhoA mutant (R68E) unable to bind RhoGDIα fails to reverse RhoB upregulation, and forced RhoGDIα expression stabilizes RhoB.\",\n      \"method\": \"RhoA siRNA, RhoA rescue expression, RhoGDIα knockdown and overexpression, RhoA-R68E mutant (RhoGDIα binding-deficient), protein half-life measurement (cycloheximide chase), Western blot\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic tools (siRNA, mutant, rescue) and biochemical readouts; single lab\",\n      \"pmids\": [\"18524772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"PKC iota (activated downstream of PI3K) represses RhoB mRNA expression; PKC iota depletion increases RhoB protein and induces actin stress fibers and reduced invasion; constitutive RhoB expression recapitulates PKC iota depletion phenotype, and RhoB and PKC iota are mutually antagonistic (RhoB overexpression represses PKC iota phosphorylation at Thr555).\",\n      \"method\": \"RNAi depletion of PKC iota, pharmacological PKC iota inhibition, gene expression microarray, RhoB ectopic expression, PKC iota phosphorylation Western blot, invasion assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi, pharmacological, and overexpression evidence with multiple readouts; single lab\",\n      \"pmids\": [\"18212741\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"An eight amino acid C-terminal sequence of RhoB directs its rapid degradation through an endo-lysosomal/multivesicular body (MVB) pathway dependent on protein isoprenylation and palmitoylation, mediated by the ESCRT machinery; RhoB sorting is regulated by late endosome-specific lipid dynamics.\",\n      \"method\": \"Chimeric protein constructs bearing RhoB C-terminal sequence, confocal microscopy in live primary cells, ultrastructural analysis, ESCRT machinery genetic perturbation, lipid traffic disease cell models\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution with chimeric proteins, ultrastructural analysis, mechanistic ESCRT pathway dissection; multiple orthogonal methods\",\n      \"pmids\": [\"19956591\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"RhoB loss promotes migration and invasiveness of bronchial cells via specific activation of Akt1 isoform and Rac1; RhoB depletion is critical for motility downstream of K-RasV12 transformation but not for cell proliferation.\",\n      \"method\": \"RNAi knockdown of RhoB, isoform-specific Akt1 activation measurement, Rac1 activation assay, migration/invasion assay, K-RasV12 transformation model\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi with pathway-specific readouts; single lab\",\n      \"pmids\": [\"19602596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"TGFβ induces RhoB transcription by an MEK/ERK-dependent pathway that recruits Smad3 to a novel non-classical Smad binding element (overlapping with CCAAT box) in the proximal RhoB promoter, in a p53-dependent manner; mutagenesis of this site abolishes Smad-mediated RhoB transactivation; RhoB is required for TGFβ-induced cell migration.\",\n      \"method\": \"siRNA knockdown, adenoviral gene transfer, MEK/MAPK inhibitors, promoter transactivation assays, Smad3 ChIP/DNA-protein interaction assays, site-directed mutagenesis, dominant-negative RhoB\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — promoter mutagenesis, ChIP/DNA-protein interaction, pharmacological and genetic dissection of pathway; multiple orthogonal methods in one study\",\n      \"pmids\": [\"19890017\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"RhoB is required for early-phase LTP in hippocampus; RhoB-null mice show reduced LTP, impaired cofilin phosphorylation in potentiated hippocampus, decreased LIMK phosphorylation, increased dendritic branching, decreased spine number, altered spine morphology (more stubby, longer, wider spines).\",\n      \"method\": \"RhoB-/- mice, electrophysiology (LTP recording), Western blot for phospho-cofilin and phospho-LIMK, dendritic morphology analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic null mice, electrophysiology, biochemical pathway readouts; single lab\",\n      \"pmids\": [\"20203211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"RhoB links PDGF signaling to cell migration by coordinating RhoB-dependent endosomal trafficking of Cdc42 from perinuclear region to cell periphery, where RhoGEF Vav2 and Rac are recruited to drive formation of circular dorsal and peripheral ruffles necessary for VSMC migration.\",\n      \"method\": \"RhoB-null vascular smooth muscle cells, GTPase activation assays for Cdc42/Rac, confocal colocalization, Vav2 recruitment assay, circular ruffle formation analysis\",\n      \"journal\": \"Journal of cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — null cells with trafficking and GTPase activation readouts; single lab\",\n      \"pmids\": [\"21344485\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"RhoB-depleted cells are rounded with defects in Rac-mediated spreading and lamellipodia, migrate faster but less persistently, have reduced surface β1 integrin levels and reduced β1 integrin activity in protrusions, and show diffuse substratum contact; RhoB contributes to directional migration by maintaining β1 integrin surface levels to stabilize lamellipodia.\",\n      \"method\": \"RNAi depletion of RhoB and GEF-H1, chemotaxis assay, surface integrin flow cytometry, integrin activity reporter, confocal microscopy, focal adhesion analysis\",\n      \"journal\": \"Open biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi with multiple functional and molecular readouts; single lab\",\n      \"pmids\": [\"22724071\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"RhoB is required for hypoxia-induced actin stress fiber formation via mDia (actin polymerization) and cooperates with RhoA/Rho kinase (MLC Ser19 phosphorylation) to maximize actomyosin contractility; RhoB is specifically required for HIF-1α stabilization, PDGF- and hypoxia-induced cell proliferation/migration; RhoB deficiency in mice attenuates chronic hypoxia-induced pulmonary hypertension.\",\n      \"method\": \"Adenoviral constitutively active RhoB, dominant-negative RhoB, farnesyltransferase inhibitor (manumycin), RhoB-/- mice, actin stress fiber imaging, MLC phosphorylation Western blot, HIF-1α stabilization assay, pulmonary hypertension model\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple genetic and pharmacological tools, in vivo mouse model, mechanistic pathway dissection with multiple orthogonal methods\",\n      \"pmids\": [\"22539766\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Nuclear RhoB-GTP controls distinct gene expression programs in blood versus lymphatic endothelial cells by regulating VEZF1-mediated transcription, underlying opposing roles of RhoB in angiogenesis versus lymphangiogenesis.\",\n      \"method\": \"RhoB null mice, chromatin/VEZF1 transcription assays, RhoB-GTP nuclear localization, primary blood and lymphatic endothelial cell culture, sprouting/proliferation assays, small-molecule VEZF1 inhibitor\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic null model, transcription factor binding assay, pharmacological inhibitor; single lab but multiple orthogonal approaches\",\n      \"pmids\": [\"24280686\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"PRK isoforms show highest affinity for RhoB compared to RhoA and RhoC; RhoB uniquely engages both the HR1a and HR1b domains of PRK1 and PRK3 (unlike RhoA and RhoC which interact only via HR1a), and PRK3 displays specific affinity for RhoB dependent on both RhoB C-terminus and PRK3 HR1b domain.\",\n      \"method\": \"In vitro binding affinity measurements (biochemical), domain deletion and mutagenesis of HR1a/HR1b, thermal stability assays for HR1 domains\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstituted binding measurements with domain mutagenesis; rigorous biochemical characterization\",\n      \"pmids\": [\"24128008\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"DNA damage activates a Chk2-HuR-RhoB pathway: DSBs induce RhoB expression via Chk2-dependent stabilization of RhoB mRNA by HuR; RhoB-deficient cells show decreased PP2A activity, fail to dephosphorylate γH2AX after camptothecin removal, and have reduced DSB repair by homologous recombination.\",\n      \"method\": \"RhoB-/- cells, Chk2 inhibition, HuR knockdown, RNA-binding assay (HuR-RhoB mRNA), PP2A activity assay, γH2AX imaging and Western blot, homologous recombination assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple loss-of-function tools, PP2A activity assay, HR repair assay, mRNA-protein interaction; multiple orthogonal methods in one study\",\n      \"pmids\": [\"24912678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The E3 ubiquitin ligase Smurf1 promotes RhoB degradation to control its basal abundance; DNA damage activates ATR/Chk1, which phosphorylates Smurf1 to enhance Smurf1 self-degradation, thereby allowing RhoB accumulation and apoptosis; overexpressing Smurf1 or blocking Chk1-dependent Smurf1 self-degradation inhibits apoptosis.\",\n      \"method\": \"Smurf1 overexpression and knockdown, Chk1 activation assays, Smurf1 phosphorylation Western blot, RhoB protein level measurements, apoptosis assay\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic perturbations and biochemical readouts; single lab\",\n      \"pmids\": [\"25249323\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"RhoB directly interacts with and positively regulates the phosphatase PP2A through recruitment of its regulatory subunit B55; this RhoB-PP2A interaction controls Akt1 dephosphorylation and opposes Rac1 activation (via Trio GEF), thereby inhibiting EMT and invasive amoeboid migration in bronchial cells.\",\n      \"method\": \"Co-immunoprecipitation of RhoB with PP2A-B55 subunit, B55 siRNA knockdown, Akt1 dephosphorylation assay, Rac1 activation assay, 3D matrix invasion assay, siRNA knockdown of Trio\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP for RhoB-PP2A interaction, siRNA rescue experiments, signaling pathway readouts; single lab\",\n      \"pmids\": [\"26148238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"BRAF inhibition induces RHOB expression via the transcription factor c-Jun; RHOB then activates AKT to promote melanoma cell survival; RHOB deficiency causes hypersensitivity to BRAF/MEK inhibitors; AKT inhibition synergizes with vemurafenib in vivo to block RHOB-positive tumor growth.\",\n      \"method\": \"BRAF/MEK inhibitor treatment, c-Jun knockdown (siRNA), RHOB siRNA, Akt activation Western blot, apoptosis assay, xenograft mouse model\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi and pharmacological pathway dissection, in vivo validation; single lab\",\n      \"pmids\": [\"26098773\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RhoB specifically inhibits endothelial barrier restoration after acute contraction by preventing plasma membrane extension; RhoB colocalizes with Rac1 in endosomes and inhibits Rac1 activity and trafficking to the cell border during barrier recovery; inhibition of endosomal trafficking impairs barrier reformation while Rac1 translocation to plasma membrane accelerates it.\",\n      \"method\": \"RhoB siRNA knockdown, Rac1 activation assay (pulldown), confocal colocalization of RhoB and Rac1 in endosomes, endosomal trafficking inhibitors, TEER measurement, plasma membrane protrusion analysis\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA, Rac1 activity assays, colocalization, pharmacological inhibition; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"27138256\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RhoB GTPase activity and its redistribution to BTN3A1 (butyrophilin A1) mediates Vγ9Vδ2 TCR activation in response to phosphoantigens in tumor cells; phosphoantigen accumulation promotes RhoB-induced cytoskeletal changes that stabilize BTN3A1 in the membrane, followed by RhoB dissociation from BTN3A1 and a BTN3A1 conformational change recognizable by Vγ9Vδ2 TCR.\",\n      \"method\": \"Genome-wide screen, RhoB GTPase activity assays, RhoB-BTN3A1 colocalization and co-immunoprecipitation, cytoskeletal analysis, TCR activation assays, BTN3A1 conformational change assay\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — unbiased genome-wide screen followed by mechanistic validation with co-IP, GTPase activity, colocalization, and functional TCR assays; multiple orthogonal methods\",\n      \"pmids\": [\"27210746\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"RhoB loss confers resistance to EGFR-TKI (erlotinib) in lung cancer via AKT activation; high RHOB expression prevents erlotinib-induced AKT inhibition in vitro and in vivo; combination of AKT inhibitor with erlotinib induces tumor cell death and regression in RHOB-positive cells.\",\n      \"method\": \"RHOB siRNA, RHOB overexpression, AKT phosphorylation Western blot, erlotinib treatment in cell lines and EGFRL858R transgenic mouse model, in vivo xenograft with AKT inhibitor combination\",\n      \"journal\": \"EMBO molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi, overexpression, transgenic mouse model, pharmacological combination; single lab with in vivo validation\",\n      \"pmids\": [\"28003335\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"The pseudogene DUXAP8 represses RhoB (and EGR1) transcription by recruiting histone demethylase LSD1 and histone methyltransferase EZH2 to the RhoB promoter, thereby promoting NSCLC cell proliferation, migration, and invasion.\",\n      \"method\": \"DUXAP8 knockdown/overexpression, LSD1/EZH2 co-IP with DUXAP8, ChIP for LSD1 and EZH2 at RhoB promoter, Western blot and qPCR for RhoB, cell functional assays\",\n      \"journal\": \"Molecular therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP and ChIP at RhoB promoter; single lab, multiple methods; note this is epigenetic regulation of RhoB expression (not RhoB protein function per se)\",\n      \"pmids\": [\"28131418\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"The Cullin-3-Rbx1-KCTD10 E3 ubiquitin ligase complex promotes K63-linked polyubiquitination of RhoB at lysines 162 and 181, targeting RhoB to lysosomes; this ubiquitination controls RhoB subcellular localization, activity, and endothelial barrier integrity by regulating RhoB-mediated endothelial cell contraction.\",\n      \"method\": \"Co-immunoprecipitation of Cullin-3/Rbx1/KCTD10 with RhoB, ubiquitination site mutagenesis (K162R/K181R), lysosome trafficking assay, endothelial permeability/TEER assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — biochemical identification of specific ubiquitination sites by mutagenesis, E3 ligase complex identified by co-IP, functional barrier readout; multiple orthogonal methods in one study\",\n      \"pmids\": [\"29358211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"DNA damage (UV, MMS) leads to ATR/Chk1-mediated phosphorylation of RhoB, which enhances RhoB interaction with TSC2 and promotes RhoB sumoylation by PIAS1; sumoylated RhoB/TSC complex translocates to lysosomes, inhibiting mTORC1 and activating autophagy; sumoylation-resistant RhoB cannot restore autophagy in RhoB-/- cells.\",\n      \"method\": \"RhoB phosphorylation and sumoylation assays, co-IP of RhoB with TSC2 and PIAS1, lysosomal fractionation, mTORC1 activity assay, autophagy assay (LC3-II), RhoB-/- cells, sumoylation-resistant RhoB mutant rescue\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — PTM identification (phosphorylation, sumoylation) with mutagenesis, co-IP for complex, fractionation for lysosomal translocation, functional mTORC1/autophagy readout; multiple orthogonal methods\",\n      \"pmids\": [\"30297842\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"KIF13A-mediated endosomal trafficking regulates RhoB plasma membrane localization: RhoB is internalized via Rab5 vesicles and trafficked to either late endosomes/lysosomes or Rab11-positive recycling endosomes; KIF13A depletion inhibits RhoB plasma membrane localization, membrane blebbing, and 3D amoeboid migration; RhoB drives membrane blebbing and amoeboid migration via downstream ROCK and Myosin II.\",\n      \"method\": \"KIF13A siRNA, live imaging of RhoB trafficking with Rab5/Rab11 markers, plasma membrane localization quantification, membrane blebbing assay, 3D-collagen migration assay, ROCK/Myosin II inhibitors\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA loss-of-function, live trafficking imaging, pharmacological effector validation, 3D functional assay; multiple orthogonal methods in one rigorous study\",\n      \"pmids\": [\"30049714\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"An intrabody (single-domain antibody) that selectively targets the GTP-bound form of RHOB (via CDR3 interaction with the GTP-binding pocket) was identified by cell-based F-box degradation screening; selective degradation of RHOB-GTP (but not total RHOB) impairs genomic instability and cell invasion, demonstrating that only the GTP-bound pool mediates these RHOB functions.\",\n      \"method\": \"Cell-based F-box/intrabody targeted protein degradation screen, intrabody-RHOB interaction mapping (CDR3/GTP-binding pocket), cell invasion assay, genomic instability assay\",\n      \"journal\": \"Cell chemical biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — novel targeted degradation screen with functional validation; single lab but mechanistically rigorous\",\n      \"pmids\": [\"31522999\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Prenylated RhoB interacts with the transcription factor DB1 (but not RhoA or H-Ras); prenylated RhoB species are present in the nuclear membrane and intranuclear laminar region; RhoB inhibits DB1-mediated transcriptional activation, suggesting a mechanism by which RhoB regulates transcription via transcription factor sequestration.\",\n      \"method\": \"Co-immunoprecipitation/binding assay (prenylation-sensitive), subcellular fractionation to nuclear membrane/intranuclear compartment, transcriptional reporter assay\",\n      \"journal\": \"Cell adhesion and communication\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single co-IP/pulldown, single transcription reporter assay; single lab\",\n      \"pmids\": [\"9865462\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"UV-induced rhoB promoter activation requires a 0.17 kb minimal promoter fragment containing TATA and CAAT boxes; overexpression of wild-type Rac or Rho-GDI activates rhoB transcription; wild-type RhoB itself inhibits both basal and UV-stimulated rhoB promoter activity, indicating a negative regulatory feedback; JNK, ERK, and p38 MAP kinase are not required for UV induction of rhoB.\",\n      \"method\": \"rhoB promoter deletion constructs/reporter assays, MEK inhibitor PD98059, p38 inhibitor SB203580, PI3K inhibitor wortmannin, Rac and Rho-GDI overexpression, run-on transcription analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter deletion analysis with multiple pathway inhibitors and overexpression; single lab, multiple orthogonal approaches\",\n      \"pmids\": [\"9388198\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RhoB is a short-lived, endosome-localized small GTPase that exists in farnesylated (RhoB-F, plasma membrane/early endosomes) and geranylgeranylated (RhoB-GG, multivesicular late endosomes) forms, undergoes rapid lysosomal degradation directed by its C-terminal sequence via ESCRT/MVB sorting, is stabilized by RhoGDIα and destabilized by Smurf1-mediated ubiquitination (and K63-ubiquitination by Cullin-3-Rbx1-KCTD10), is transcriptionally induced by DNA damage, UV, TGFβ, and hypoxia, and is repressed by Ras/PI3K/Akt signaling and HDAC1-mediated histone deacetylation; mechanistically, RhoB coordinates endosomal trafficking of receptor tyrosine kinases (EGFR, PDGFR-β, CXCR2) and signaling molecules (Src, Akt, Cdc42, Rac1), regulates actin dynamics via the ROCK/LIMK/cofilin axis and mDia-mediated polymerization, promotes DSB repair via a Chk2-HuR-RhoB-PP2A pathway, drives autophagy through ATR/Chk1-phosphorylation-dependent sumoylation and lysosomal recruitment of the TSC complex to inhibit mTORC1, activates NF-κB via ROCK I (preferentially in its farnesylated form), and binds PRK isoforms (with highest affinity through both HR1a and HR1b domains) to regulate downstream signaling and cell transformation suppression.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RHOB is a rapidly turned-over, endosome-associated small GTPase that governs the intracellular trafficking and spatial activation of receptor tyrosine kinases and signaling proteins, coupling these functions to growth suppression, stress responses, and cytoskeletal control [#0, #6]. Distinct from RhoA, RHOB localizes to the cytosolic face of endocytic vesicles and the perinuclear recycling compartment, where it controls the sorting of cargo such as EGFR, PDGFR-\\u03b2, and CXCR2 between lysosomal degradation and recycling routes, and is required for the catalytic activation and membrane delivery of c-Src and the trafficking of Cdc42 and Rac1 [#0, #20, #23, #6, #30]. RHOB exists as farnesylated and geranylgeranylated species whose prenylation state dictates membrane targeting and function: geranylgeranylated RHOB suppresses Ras-mediated transformation, induces p21WAF1 and apoptosis, and mediates the antineoplastic effects of farnesyltransferase inhibitors, with genetic ablation rendering Ras-transformed cells defective in FTI-induced apoptosis [#1, #2, #3, #13]. RHOB acts as a tumor suppressor downstream of oncogenic signaling, being transcriptionally repressed by Ras/PI3K/Akt and HDAC1, and induced by DNA damage, UV, TGF\\u03b2, and hypoxia [#10, #9, #28, #35]; its abundance is set by isoprenylation-dependent endo-lysosomal degradation directed by an eight-residue C-terminal sequence routed through the ESCRT/MVB pathway, by Smurf1- and Cullin-3\\u2013Rbx1\\u2013KCTD10-mediated ubiquitination, and by RhoGDI\\u03b1-dependent stabilization [#26, #36, #43, #24]. Mechanistically, RHOB drives actin remodeling through the ROCK/LIMK/cofilin and mDia axes, activates NF-\\u03baB via ROCK I in its farnesylated form, promotes homologous-recombination DSB repair through a Chk2-HuR-RhoB-PP2A pathway, and triggers autophagy by ATR/Chk1-dependent phosphorylation and PIAS1-mediated sumoylation that recruits the TSC complex to lysosomes to inhibit mTORC1 [#32, #19, #35, #44]. RHOB binds PRK isoforms with high affinity through both HR1a and HR1b domains and only its GTP-bound pool mediates genomic instability and invasion [#34, #46].\"\n,\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Established how rhoB transcription is controlled, defining a minimal stress-responsive promoter and a negative autoregulatory loop, framing RhoB as an inducible immediate stress gene.\",\n      \"evidence\": \"rhoB promoter deletion/reporter assays with MAPK and PI3K inhibitors and Rac/Rho-GDI overexpression\",\n      \"pmids\": [\"9388198\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not identify the transcription factors binding the minimal element\", \"Mechanism of RhoB-mediated negative feedback unresolved\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"First linked prenylated RhoB to nuclear transcription factor sequestration, raising the possibility that RhoB regulates transcription directly.\",\n      \"evidence\": \"Prenylation-sensitive co-IP with transcription factor DB1, nuclear fractionation, reporter assays\",\n      \"pmids\": [\"9865462\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single co-IP and single reporter assay without reciprocal validation\", \"Identity and significance of DB1 target genes not established\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Defined RhoB's distinguishing endosomal localization and showed it controls EGFR trafficking kinetics via PRK1, separating it functionally from plasma-membrane RhoA.\",\n      \"evidence\": \"Subcellular imaging, PRK1 binding assays, dominant-active/negative mutants, EGFR trafficking assays\",\n      \"pmids\": [\"10508588\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GTPase cycle regulators on endosomes not identified\", \"Connection between PRK1 binding and trafficking kinetics mechanistically incomplete\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Demonstrated that the geranylgeranylated RhoB species gained upon FTI treatment is sufficient to revert Ras transformation and induce p21WAF1, mechanistically linking RhoB to FTI action.\",\n      \"evidence\": \"Ectopic RhoB-GG expression in Ras-transformed and human carcinoma cells, colony/cell-cycle/apoptosis assays, p21WAF1 blots\",\n      \"pmids\": [\"10022870\", \"10554025\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why RhoB-GG selectively affects transformed but not normal cells unresolved\", \"Direct effectors downstream of RhoB-GG growth suppression not defined\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Provided genetic proof via rhoB-null cells that RhoB is a crucial mediator of FTI-induced apoptosis and antitumor responses, and showed both prenyl forms suppress growth and Akt/Erk signaling.\",\n      \"evidence\": \"rhoB gene knockout with E1A+H-Ras transformation, FTI treatment, apoptosis and xenograft assays, Akt/Erk blots\",\n      \"pmids\": [\"10913192\", \"10770919\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular target by which RhoB triggers apoptosis not identified\", \"How RhoB inhibits Akt/Erk activation mechanistically unresolved\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Resolved the basis of RhoB's short half-life by showing isoprenylation is required for its rapid proteasomal degradation, explaining statin-mediated RhoB upregulation.\",\n      \"evidence\": \"Isoprenylation-deficient mutants, statin treatment with metabolite rescue, protein half-life measurements\",\n      \"pmids\": [\"12384510\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"The degradation machinery recognizing prenylated RhoB not yet identified\", \"Reconciliation with later endo-lysosomal degradation route incomplete\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Connected RhoB endosomes to spatial control of signaling kinases and survival, showing RhoB is required for c-Src activation, Akt nuclear trafficking, and endothelial survival.\",\n      \"evidence\": \"RhoB knockout cells, live c-Src/Akt imaging, kinase activity assays, proteasome inhibitor rescue, RhoB-null mice\",\n      \"pmids\": [\"15572128\", \"14597666\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RhoB couples endosome movement to kinase activation mechanistically open\", \"Direct RhoB effectors mediating Akt nuclear import not identified\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identified HDAC1 as a transcriptional repressor of RhoB acting through an inverted CCAAT box, and showed RhoB drives a ROCK1/LIMK1/cofilin pathway in junction dynamics.\",\n      \"evidence\": \"HDAC1 antisense, HDAC inhibitor and promoter reporter assays; immunoprecipitation, phospho-LIMK1 assays, ROCK inhibition in Sertoli-germ cell models\",\n      \"pmids\": [\"13679859\", \"12606349\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Factors recruiting HDAC1 to the RhoB promoter not defined\", \"Direct GEF activating RhoB at junctions unidentified\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Established that Ras represses RhoB via PI3K/Akt and that prenylation form determines opposing functions, with RhoB-GG suppressing and RhoB-F enhancing transformation.\",\n      \"evidence\": \"PI3K/Akt/MEK inhibitors, prenylation-specific mutants, promoter reporter assays, transformation/apoptosis readouts, EGFR/ErbB2/Ras oncogene panel\",\n      \"pmids\": [\"15169915\", \"14647415\", \"15748883\", \"15226397\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular determinant of opposite RhoB-F vs RhoB-GG outputs unresolved\", \"Link between prenyl-defined endosomal localization and transcriptional suppression incomplete\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined the C-terminal lipid modifications (palmitoylation of Cys192 and prenylation) as determinants of RhoB localization and tumor-suppressive/proapoptotic activity, and dissected prenyl-form-specific radiation and UVB responses.\",\n      \"evidence\": \"Site-directed mutagenesis, RhoA/RhoB chimera, promoter and apoptosis assays; GTP-RhoB pulldown, EGFR inhibitor, clonogenic and centrosome assays\",\n      \"pmids\": [\"15713677\", \"16278215\", \"15776002\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Palmitoyltransferase responsible for Cys192 modification not identified\", \"How localization translates to transcriptional suppression mechanistically open\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Showed FTI/GGTI upregulate RhoB transcriptionally via chromatin remodeling (HDAC1 dissociation, HAT recruitment, histone acetylation) and that LPS-TRIF signaling activates RhoB through GEF-H1 to drive MHCII surface expression.\",\n      \"evidence\": \"ChIP for HDAC1/HAT on RhoB promoter, RT-PCR; dominant-negative/RNAi RhoB, GEF-H1 co-IP, GTPase pulldown, MHCII and T cell assays\",\n      \"pmids\": [\"16909123\", \"16917499\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Signal connecting prenylation inhibition to promoter chromatin state unresolved\", \"How RhoB directs MHCII+ lysosome trafficking mechanistically incomplete\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Expanded RhoB's trafficking role across PDGFR-\\u03b2, CXCR2, and SFK cargoes, established ROCK I as the NF-\\u03baB-activating effector of farnesylated RhoB, and defined integrin-dependent migration phenotypes.\",\n      \"evidence\": \"RhoB-null cells with rescue, receptor sorting/recycling assays, SFK colocalization and kinase assays, NF-\\u03baB reporters with ROCK I inhibition, integrin flow cytometry and migration assays\",\n      \"pmids\": [\"17951322\", \"17405813\", \"17623777\", \"17728102\", \"17692842\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RhoB GTPase oscillation directs sorting decisions mechanistically unresolved\", \"Mechanism by which RhoB-F selects ROCK I over PRK I for NF-\\u03baB not defined\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Identified RhoGDI\\u03b1, made available by RhoA-GDP, as a stabilizer of RhoB protein, and PKC iota as a PI3K-driven repressor of RhoB, defining mutually antagonistic regulation.\",\n      \"evidence\": \"RhoA/RhoGDI\\u03b1 siRNA, rescue and binding-deficient mutants, cycloheximide chase; PKC iota RNAi/inhibition, microarray, invasion assays\",\n      \"pmids\": [\"18524772\", \"18212741\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of RhoGDI\\u03b1-RhoB stabilization not defined\", \"Direct transcriptional effectors of PKC iota repression unidentified\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Defined the C-terminal eight-residue ESCRT/MVB degradation signal, showed RhoB loss enables Akt1/Rac1-driven invasion, and revealed RhoB's role in synaptic plasticity via cofilin signaling.\",\n      \"evidence\": \"Chimeric C-terminal constructs, ultrastructure, ESCRT perturbation; RhoB RNAi with isoform-specific Akt1/Rac1 assays; RhoB-null mice LTP and dendritic morphology\",\n      \"pmids\": [\"19956591\", \"19602596\", \"20203211\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Adaptors linking the C-terminal signal to ESCRT recognition not identified\", \"How loss of RhoB selectively activates Akt1 isoform unresolved\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showed TGF\\u03b2 induces RhoB transcription via MEK/ERK-dependent Smad3 recruitment to a non-classical element, integrating RhoB into TGF\\u03b2-driven migration.\",\n      \"evidence\": \"Promoter mutagenesis, Smad3 ChIP/DNA-protein assays, MEK inhibitors, dominant-negative RhoB, migration assays\",\n      \"pmids\": [\"19890017\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"p53 requirement mechanism at the promoter not fully defined\", \"Downstream RhoB effectors for TGF\\u03b2 migration unresolved\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Established that RhoB coordinates endosomal trafficking of Cdc42 to the periphery, recruiting Vav2/Rac to drive ruffle formation and VSMC migration, integrating its cargo-sorting role with motility.\",\n      \"evidence\": \"RhoB-null VSMCs, Cdc42/Rac GTPase activation assays, Vav2 recruitment and ruffle analysis, confocal colocalization\",\n      \"pmids\": [\"21344485\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How RhoB selects Cdc42 as endosomal cargo unresolved\", \"Direct RhoB effector mediating Cdc42 transport not identified\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Connected RhoB to hypoxia responses, showing it is required for HIF-1\\u03b1 stabilization and cooperates with mDia and RhoA/ROCK for actomyosin contractility, with in vivo consequences for pulmonary hypertension; refined integrin-dependent directional migration.\",\n      \"evidence\": \"Constitutively active/dominant-negative RhoB, FTI, RhoB-null mice, stress fiber and MLC phosphorylation assays, pulmonary hypertension model; RhoB/GEF-H1 RNAi with integrin and migration readouts\",\n      \"pmids\": [\"22539766\", \"22724071\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which RhoB stabilizes HIF-1\\u03b1 not defined\", \"How RhoB maintains \\u03b21 integrin surface levels mechanistically open\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified nuclear RhoB-GTP as a regulator of VEZF1-dependent transcription programs distinguishing blood from lymphatic endothelium, and mapped PRK domain selectivity, showing RhoB uniquely engages both HR1a and HR1b.\",\n      \"evidence\": \"RhoB-null mice, VEZF1 transcription assays, nuclear RhoB-GTP localization; in vitro PRK binding affinity and HR1a/HR1b domain mutagenesis\",\n      \"pmids\": [\"24280686\", \"24128008\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How nuclear RhoB-GTP is generated and regulated unresolved\", \"Functional consequence of dual HR1a/HR1b PRK engagement in cells not established\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined a DNA damage axis in which Chk2-HuR stabilizes RhoB mRNA to promote PP2A-dependent \\u03b3H2AX dephosphorylation and homologous-recombination repair, while ATR/Chk1-driven Smurf1 self-degradation allows RhoB accumulation and apoptosis.\",\n      \"evidence\": \"RhoB-null cells, Chk2 inhibition, HuR knockdown and RNA-binding assays, PP2A activity and HR assays; Smurf1 overexpression/knockdown, Chk1 and phosphorylation assays, apoptosis readout\",\n      \"pmids\": [\"24912678\", \"25249323\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RhoB activates PP2A toward \\u03b3H2AX mechanistically incomplete\", \"Substrate specificity of Smurf1 toward RhoB not structurally defined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Established RhoB as a direct positive regulator of PP2A via the B55 subunit controlling Akt1 dephosphorylation and Rac1 antagonism, and identified c-Jun-driven RHOB induction promoting AKT-dependent melanoma survival under BRAF inhibition.\",\n      \"evidence\": \"RhoB-PP2A-B55 co-IP, B55/Trio siRNA, Akt1/Rac1 activity and 3D invasion assays; BRAF/MEK inhibitors, c-Jun and RHOB siRNA, AKT blots, xenografts\",\n      \"pmids\": [\"26148238\", \"26098773\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of RhoB-PP2A-B55 recruitment not defined\", \"Context-dependence of RhoB promoting vs opposing AKT unresolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Revealed RhoB-dependent endosomal sequestration of Rac1 in endothelial barrier recovery and a phosphoantigen-sensing role at BTN3A1 for V\\u03b39V\\u03b42 TCR activation, broadening RhoB's spatial-regulatory repertoire.\",\n      \"evidence\": \"RhoB siRNA, Rac1 activity assays, endosomal colocalization and trafficking inhibitors, TEER; genome-wide screen, RhoB-BTN3A1 co-IP/colocalization, TCR activation and conformation assays\",\n      \"pmids\": [\"27138256\", \"27210746\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RhoB GTPase cycling times BTN3A1 stabilization and release unresolved\", \"Mechanism of RhoB-mediated Rac1 retention in endosomes not defined\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified RHOB as a determinant of EGFR-TKI sensitivity through AKT regulation, and uncovered pseudogene DUXAP8-mediated epigenetic silencing of RhoB via LSD1/EZH2 recruitment.\",\n      \"evidence\": \"RHOB siRNA/overexpression, AKT blots, erlotinib in cells and EGFRL858R mice, AKT-inhibitor combination; DUXAP8 perturbation, LSD1/EZH2 co-IP and ChIP at RhoB promoter, functional assays\",\n      \"pmids\": [\"28003335\", \"28131418\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How RHOB level dictates AKT response to TKI mechanistically incomplete\", \"Whether DUXAP8 silencing operates broadly across cancers unresolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined post-translational control of RhoB localization and function: Cullin-3\\u2013Rbx1\\u2013KCTD10 K63-ubiquitination targets RhoB to lysosomes, KIF13A-mediated endosomal trafficking sets plasma-membrane RhoB driving blebbing/amoeboid migration, and ATR/Chk1 phosphorylation plus PIAS1 sumoylation route a RhoB-TSC complex to lysosomes to inhibit mTORC1 and activate autophagy.\",\n      \"evidence\": \"Cullin-3/Rbx1/KCTD10 co-IP and K162R/K181R mutagenesis with TEER; KIF13A siRNA, live trafficking imaging, ROCK/Myosin II inhibitors, 3D migration; RhoB phospho/sumoylation assays, TSC2/PIAS1 co-IP, lysosomal fractionation, mTORC1/autophagy readouts\",\n      \"pmids\": [\"29358211\", \"30049714\", \"30297842\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How distinct ubiquitin/sumoylation marks are selected for different fates unresolved\", \"Coordination between trafficking, mTORC1 inhibition, and degradation pathways incomplete\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrated with a GTP-state-selective intrabody degrader that only the GTP-bound RHOB pool mediates genomic instability and invasion, distinguishing active-form function from total protein.\",\n      \"evidence\": \"Cell-based F-box/intrabody targeted degradation screen, CDR3/GTP-pocket interaction mapping, invasion and genomic instability assays\",\n      \"pmids\": [\"31522999\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GEFs/GAPs setting the GTP-bound RHOB pool in these contexts not identified\", \"Whether GTP-selective targeting is therapeutically tractable unestablished\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RhoB integrates its many prenyl-form-, ubiquitin-, sumoyl-, and phosphorylation-dependent states with specific GEF/GAP regulators to select among trafficking, transcriptional, repair, autophagy, and contractility outputs in a given cell remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model linking PTM-defined RhoB states to specific effector choices\", \"Endosomal GEFs/GAPs controlling the RhoB GTPase cycle largely unidentified\", \"Structural basis for prenyl-form-specific effector selection (ROCK I vs PRK) lacking\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003924\", \"supporting_discovery_ids\": [0, 15, 18, 23, 40, 46]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [6, 7, 35, 37]},\n      {\"term_id\": \"GO:0140313\", \"supporting_discovery_ids\": [47, 44]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [0, 6, 11, 23, 30, 39, 45]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [26, 43, 44, 11]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [11, 45, 40]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [7, 33, 47]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 11, 20, 23, 30, 45]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [6, 26, 43, 45]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10, 15, 19, 38, 41]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [35]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [44]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [3, 4, 7, 36]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [9, 17, 28, 33, 42, 48]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [1, 2, 3, 38, 41]}\n    ],\n    \"complexes\": [\n      \"RhoB-PP2A (B55) complex\",\n      \"Cullin-3\\u2013Rbx1\\u2013KCTD10 E3 ligase complex\",\n      \"RhoB-TSC complex\"\n    ],\n    \"partners\": [\n      \"PRK1\",\n      \"PP2A\",\n      \"Smurf1\",\n      \"KCTD10\",\n      \"TSC2\",\n      \"PIAS1\",\n      \"RhoGDI\\u03b1\",\n      \"GEF-H1\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}