{"gene":"RRAS","run_date":"2026-06-14T07:33:11","timeline":{"discoveries":[{"year":1987,"finding":"R-Ras p23 protein is palmitoylated (3H-palmitate labeling) and associates with the P100 membrane fraction; it exhibits GTP-binding activity analogous to H-Ras p21, and a threonine 85 substitution mutant undergoes GTP-dependent phosphorylation (autokinase activity analogous to H-Ras T59 mutants).","method":"Immunoprecipitation, metabolic labeling with [3H]palmitate, membrane fractionation, GTP-dependent phosphorylation assay in E. coli-expressed protein","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct biochemical assays with purified/expressed protein and multiple orthogonal methods in the original characterization paper","pmids":["3313005"],"is_preprint":false},{"year":1989,"finding":"R-Ras (p23) interacts with the same 125-kDa rasGAP protein as p21ras (not with the 29-kDa rhoGAP), demonstrating that R-Ras GTPase activity is stimulated by the canonical rasGAP in a manner dependent on the effector domain.","method":"GTPase-activating assay using mammalian cytoplasmic extracts, GTPase activity measurements","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro GTPase assay directly measuring GAP activity, replicated across multiple Ras family members as controls","pmids":["2491843"],"is_preprint":false},{"year":1989,"finding":"Certain phospholipids inhibit the interaction between R-Ras and its GTPase-activating protein (GAP), with inhibitory lipids differing from those blocking ras-GAP interaction, suggesting lipid-mediated regulation of R-Ras GAP interaction.","method":"In vitro GTPase-activating assay with defined lipids added","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro biochemical assay, single lab, single method","pmids":["2513485"],"is_preprint":false},{"year":1993,"finding":"Bcl-2 physically associates with R-Ras p23; the C-terminal 60 amino acids of R-Ras are sufficient for this interaction, which was detected by yeast two-hybrid and co-immunoprecipitation from human cell extracts.","method":"Yeast two-hybrid screen, co-immunoprecipitation from human cell extracts","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal yeast two-hybrid plus co-IP from endogenous cellular extracts, two orthogonal methods in one study","pmids":["8232588"],"is_preprint":false},{"year":1994,"finding":"R-Ras directly interacts with Raf-1 in a GTP-dependent manner; this interaction requires the N-terminal regulatory domain (aa 1–256) of Raf-1 and the effector domain of R-Ras, as demonstrated by yeast two-hybrid and direct in vitro binding with purified proteins.","method":"Yeast two-hybrid, in vitro binding assay with purified R-Ras and Raf-1 Ras-binding domain (aa 51–131)","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro reconstitution with purified proteins plus yeast two-hybrid, two orthogonal methods","pmids":["8002932"],"is_preprint":false},{"year":1994,"finding":"R-Ras interacts with RalGDS (Ral guanine nucleotide dissociation stimulator) in a GTP-dependent manner via the RalGDS Ras-binding domain (RBD), identified by yeast two-hybrid screening; direct GTP-dependent interaction confirmed with purified proteins in vitro; RalGDS-RBD and Raf-1 RBD compete for binding to R-Ras.","method":"Yeast two-hybrid library screen, in vitro binding assay with purified proteins","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Moderate — yeast two-hybrid plus reconstituted in vitro binding with purified proteins, two orthogonal methods","pmids":["7809086"],"is_preprint":false},{"year":1994,"finding":"R-Ras interacts with the catalytic domain of rasGAP and with the GAP-related domain of neurofibromin in vitro, and stimulates c-fos expression when microinjected into Swiss 3T3 cells, but unlike Ras does not induce DNA synthesis, membrane ruffling, oocyte maturation, or PC12 differentiation.","method":"In vitro binding assays, microinjection into fibroblasts, gene expression assays","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro binding plus cell microinjection with defined readouts, two methods in one study","pmids":["8108110"],"is_preprint":false},{"year":1994,"finding":"Oncogenic activation of R-Ras by point mutations at codon 38 (analogous to Ras codon 12) or codon 87 (analogous to codon 61) confers transforming capacity; R-Ras cooperates with c-raf-1 in NIH3T3 transformation, suggesting interaction with the Raf signaling pathway.","method":"Site-directed mutagenesis, NIH3T3 focus formation assay, soft-agar colony assay, in vivo tumor assay, co-transfection with c-raf-1","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple functional assays (focus formation, soft agar, tumorigenicity) plus genetic epistasis with c-raf-1, well-replicated activation mechanism","pmids":["8084601"],"is_preprint":false},{"year":1995,"finding":"A novel ~98-kDa R-Ras-specific GTPase-activating protein (R-Ras GAP) was purified from bovine brain; it binds GTP-bound R-Ras but not GDP-R-Ras, effector-domain-mutant R-Ras, Ha-Ras, or RalA; its GAP-related domain stimulates GTPase activity of R-Ras and weakly of Ha-Ras, but not Rap1 or Rho.","method":"GST-R-Ras affinity chromatography, GTPase activity assay with recombinant GAP domain, protein purification and cDNA cloning","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstituted in vitro GAP activity assay with purified proteins and domain mutagenesis, two orthogonal methods","pmids":["8530488"],"is_preprint":false},{"year":1995,"finding":"Activated R-Ras (38V) promotes apoptosis upon growth factor withdrawal via a Bcl-2-suppressible mechanism; Bcl-2 does not alter R-Ras GTP/GDP ratio or inhibit R-Ras-mediated Raf-1 activation, placing Bcl-2 downstream of R-Ras in the cell death pathway.","method":"Stable transfection of R-Ras(38V), IL-3 withdrawal apoptosis assay, co-transfection with Bcl-2, in vitro GTPase assay, Raf-1 kinase assay in Sf9 cells","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (cell death assays, GTPase assay, Raf kinase assay, baculovirus co-expression), clear epistatic placement of Bcl-2 downstream of R-Ras","pmids":["7744959"],"is_preprint":false},{"year":1996,"finding":"Expression of constitutively active R-Ras increases integrin ligand-binding affinity without changing integrin surface expression; dominant-negative R-Ras reduces adhesion of endogenous cells, establishing R-Ras as a regulator of integrin activation (inside-out signaling).","method":"Stable transfection of activated/dominant-negative R-Ras mutants, integrin ligand-binding affinity assays, cell adhesion assays, fibronectin matrix assembly assay","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — gain- and loss-of-function with multiple functional readouts; foundational paper, widely replicated","pmids":["8620538"],"is_preprint":false},{"year":1996,"finding":"R-Ras binds to the Raf-1 RBD and RalGDS RBD with weak affinity and no specificity compared to H-Ras/Raf or Rap1A/RalGDS interactions; biochemical solution binding assays show Rap1A, not R-Ras, is the likely physiological effector of RalGDS.","method":"Solution binding assays (quantitative affinity measurements), guanine nucleotide dissociation inhibition assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — quantitative in vitro binding with purified proteins, kinetic measurements, multiple Ras family members compared","pmids":["8636102"],"is_preprint":false},{"year":1997,"finding":"R-Ras activates PI 3-kinase in vitro and elevates PI 3-kinase lipid products in cells, and activates PKB/Akt through a PI 3-kinase-dependent mechanism; unlike Ras, R-Ras does not activate Raf or MAP kinase in cells.","method":"Co-transfection assays, PI 3-kinase lipid product measurements, PKB/Akt kinase assays, MAP kinase assays, PI 3-kinase inhibitor (wortmannin)","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple kinase assays, inhibitor validation, PI3K lipid measurements; independently replicated across multiple studies","pmids":["8999998"],"is_preprint":false},{"year":1999,"finding":"EphB2 receptor tyrosine kinase phosphorylates tyrosine 66 in the R-Ras effector domain upon activation, reducing integrin activity and cell adhesion; an R-Ras Y66F mutant resistant to phosphorylation renders cells unresponsive to EphB2-mediated anti-adhesion.","method":"EphB2 activation assays, phosphorylation mapping by site-directed mutagenesis (Y66F), cell adhesion assays, transfection rescue experiments","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — phosphorylation site identified by mutagenesis, functional rescue experiment confirms causal relationship","pmids":["10570155"],"is_preprint":false},{"year":1999,"finding":"SHEP1 (SH2 domain-containing Eph receptor-binding protein 1) directly links activated EphB2 to R-Ras: SHEP1's SH2 domain binds the phosphorylated juxtamembrane region of EphB2, and SHEP1's Ras-GEF-like domain binds R-Ras and Rap1A (but not Ha-Ras or RalA).","method":"Yeast two-hybrid screen, co-immunoprecipitation, domain-mapping experiments","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — yeast two-hybrid plus co-IP, two methods but no direct GEF exchange assay performed","pmids":["10542222"],"is_preprint":false},{"year":1999,"finding":"Activated R-Ras (38V) and TC21 promote integrin-mediated migration and invasion of breast epithelial cells through integrin alpha2 (but not alpha5) cytoplasmic domain-dependent signaling, via a combination of PI 3-kinase and PKC (but not MAPK) pathways.","method":"Stable transfection, integrin cytoplasmic domain chimeras, cell migration and invasion assays, pharmacological pathway inhibitors","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — integrin chimera specificity assay plus pharmacological dissection, multiple readouts in one study","pmids":["10352023"],"is_preprint":false},{"year":1999,"finding":"GTP-bound R-Ras antagonizes the Ras/Raf-initiated integrin suppression pathway without competing for common downstream effectors or inhibiting Ras/Raf-induced MAP kinase activation, suggesting distinct downstream effectors.","method":"CHO cell transfection, integrin affinity assays, MAP kinase activation assays, dominant-negative/constitutively active mutant expression","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — clean cell-based epistasis, single lab, single main method","pmids":["10359597"],"is_preprint":false},{"year":1999,"finding":"R-Ras effector domain mutants (S61, G63, C66) dissociate transforming activity from cell adhesion/survival promotion; PI 3-kinase (but not MEK-dependent MAPK) is essential for R-Ras oncogenicity; Akt inhibition blocks R-Ras pro-survival effects; dominant-negative Rac and Ral suppress R-Ras-induced cell adhesion.","method":"Effector loop mutagenesis, transformation assays, dominant-negative kinase co-expression, PI3K inhibitor LY294002, cell adhesion/survival assays in 32D cells","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic effector loop mutagenesis plus pharmacological and genetic dissection across multiple biological readouts","pmids":["10454580"],"is_preprint":false},{"year":2000,"finding":"R-Ras guanine nucleotide exchange is promoted by RasGRF, C3G, CalDAG-GEFI, CalDAG-GEFII (RasGRP), and CalDAG-GEFIII both in 293T cells and in vitro; R-Ras GTPase activity is stimulated by Gap1(m), p120 GAP, NF-1, and R-Ras GAP (but not by exchange factors or GAPs for classical Ras exclusively).","method":"GTP/GDP ratio measurements in 293T cells, in vitro GEF assays, GAP activity assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro biochemical GEF and GAP assays plus cell-based measurements, systematic comparison of multiple regulators","pmids":["10777492"],"is_preprint":false},{"year":2000,"finding":"CalDAG-GEFIII (also called CalDAG-GEFIII) promotes guanine nucleotide exchange on R-Ras (as well as Ha-Ras and Rap1) both in 293T cells and in vitro, demonstrating that R-Ras is a substrate of this calcium/DAG-regulated GEF.","method":"GTP/GDP ratio assay in 293T cells, in vitro GEF assay with purified proteins","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstituted exchange assay plus cell-based measurement, two methods","pmids":["10835426"],"is_preprint":false},{"year":2000,"finding":"AND-34 (BCAR3 homolog) exhibits GEF activity on R-Ras (as well as RalA and Rap1A) in cells; its GEF activity is regulated by binding to p130Cas, with overexpression of p130Cas inhibiting AND-34's Ral GEF activity.","method":"GTP/GDP exchange assay in cells, co-immunoprecipitation, dominant-negative construct co-expression","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — cell-based GEF assay plus co-IP, single lab, limited in vitro validation","pmids":["10896938"],"is_preprint":false},{"year":2000,"finding":"Activated R-Ras, PI 3-kinase, PKCε, and Rac1 can each restore cell spreading inhibited by tac-β1 dominant-negative integrin; R-Ras-mediated rescue of cell spreading requires intact integrin β cytoplasmic domains and PI 3-kinase activity (blocked by LY294002), placing R-Ras upstream of PI 3-kinase in integrin-dependent spreading.","method":"Tac-β1 dominant-negative expression, PI 3-kinase inhibitor LY294002, cell spreading area measurements, co-expression of signaling mutants","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic rescue epistasis with pharmacological inhibitor validation, multiple constructs tested","pmids":["11134082"],"is_preprint":false},{"year":2000,"finding":"Ha-Ras activates α5β1 integrin via PI 3-kinase p110δ, while R-Ras activates α5β1 via a distinct PI 3-kinase-independent pathway; R-Ras effector loop mutations affecting cell adhesion do not correlate with PI3K activity.","method":"Integrin adhesion assays in mast cells, wortmannin inhibition, effector loop mutants, PI3K co-immunoprecipitation, Akt phosphorylation assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — comparative mutant analysis plus pharmacological inhibition, single lab","pmids":["10801791"],"is_preprint":false},{"year":2000,"finding":"R-Ras contains a proline-rich motif that binds the second SH3 domain of the adaptor protein Nck in a GTP-independent manner; mutations in this proline-rich site suppress R-Ras-mediated cell adhesion without affecting GTP binding.","method":"GST-SH3 pulldown, yeast two-hybrid, co-immunoprecipitation from transfected cells, site-directed mutagenesis, cell adhesion assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal binding methods plus functional mutagenesis with adhesion readout","pmids":["10671570"],"is_preprint":false},{"year":2001,"finding":"R-Ras activates Rap1-dependent αMβ2 integrin-mediated phagocytosis in macrophages but does not activate ERK, JNK, or p38 MAPK pathways; microinjection of activated R-Ras into PC12 cells induces cell spreading rather than differentiation.","method":"Microinjection of constitutively active R-Ras into fibroblasts and PC12 cells, phagocytosis assay in macrophage cell line, MAP kinase assays","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — microinjection with defined functional readouts, multiple cell types tested, single lab","pmids":["11257001"],"is_preprint":false},{"year":2001,"finding":"Activated Src kinase (v-Src and Src527) phosphorylates R-Ras at tyrosine 66 in vitro and in cells, suppressing integrin activity; R-Ras and Src co-immunoprecipitate in temperature-sensitive v-Src cells at the permissive temperature; R-Ras Y66F mutant confers partial resistance to Src-mediated loss of adhesion.","method":"In vitro kinase assay, endogenous R-Ras phosphorylation in Src-transformed cells, co-immunoprecipitation, site-directed mutagenesis (Y66F), cell adhesion assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro kinase assay plus cell-based phosphorylation, co-IP, and functional mutagenesis rescue; multiple orthogonal methods","pmids":["11682467"],"is_preprint":false},{"year":2002,"finding":"Toxin B variants from toxin A-negative C. difficile strains glucosylate R-Ras (a post-translational modification), causing cell detachment from ECM and blocking EGF-mediated ERK phosphorylation; constitutively active R-Ras expression protects cells against cytopathic effect, confirming R-Ras as the functional target.","method":"Glucosylation assay, constitutively active R-Ras rescue transfection, cell adhesion/detachment assay, ERK phosphorylation assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct biochemical glucosylation assay plus genetic rescue with constitutively active R-Ras, multiple functional readouts","pmids":["12496290"],"is_preprint":false},{"year":2003,"finding":"Activated R-Ras promotes focal adhesion formation and dramatically enhances FAK and p130Cas phosphorylation upon collagen stimulation or α2β1 integrin clustering; this signaling is partially PI 3-kinase dependent but Src-independent and distinct from canonical integrin signaling.","method":"Stable transfection of R-Ras(38V), phospho-FAK and p130Cas immunoblotting, Src and PI3K inhibitors, integrin clustering experiments","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological and genetic pathway dissection with multiple signaling readouts, single lab","pmids":["12529399"],"is_preprint":false},{"year":2003,"finding":"The C-terminal hypervariable region (aa 175–218) of R-Ras contains a focal adhesion targeting signal; palmitoylation at C213 is required for Golgi exit and plasma membrane targeting; activated R-Ras (but not dominant-negative R-Ras) localizes to focal adhesions in a GTP-dependent manner.","method":"H-Ras/R-Ras chimera analysis, palmitoylation site mutagenesis (C213A), subcellular fractionation, immunofluorescence localization","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic chimera analysis plus palmitoylation mutagenesis, defining the targeting sequence and lipid modification requirement with functional consequences","pmids":["12890755"],"is_preprint":false},{"year":2003,"finding":"ORP3 (OSBP-related protein 3) interacts with R-Ras; siRNA knockdown of ORP3 phenocopies constitutively active R-Ras (enhanced β1 integrin activity, altered actin); ORP3 overexpression reduces β1 integrin activity; ORP3 is phosphorylated when cells lose adhesive contacts.","method":"Co-immunoprecipitation, siRNA knockdown, β1 integrin activity assay (FACS), phagocytosis assay, actin cytoskeleton analysis","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP binding plus siRNA phenocopy experiments, multiple readouts, single lab","pmids":["18270267"],"is_preprint":false},{"year":2004,"finding":"Plexin-B1 directly stimulates the intrinsic GTPase activity of R-Ras; this GAP activity requires the interaction of Plexin-B1 with Rnd1 (a Rho-family GTPase); R-Ras inactivation by the Plexin-B1–Rnd1 complex is essential for Sema4D-induced growth cone collapse in hippocampal neurons.","method":"R-Ras GTPase activity assay (GAP assay), co-immunoprecipitation of Plexin-B1 and Rnd1, Sema4D-induced growth cone collapse assay in primary hippocampal neurons, dominant-negative constructs","journal":"Science (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro GAP assay plus co-IP and primary neuron functional assay; foundational mechanistic study widely replicated","pmids":["15297673"],"is_preprint":false},{"year":2004,"finding":"The Plexin-B1 cytoplasmic domain contains C1 and C2 R-Ras GAP-homologous domains; Rnd1 disrupts an intramolecular C1–C2 interaction to open the GAP domains; Sema4D-induced receptor clustering activates R-Ras GAP activity; deletion of the extracellular domain causes ligand-independent clustering and constitutive R-Ras GAP activity.","method":"Domain deletion and mutagenesis of Plexin-B1, antibody-induced clustering of recombinant cytoplasmic domain, R-Ras GTPase activation assay, COS-7 cell contraction assay, hippocampal neurite outgrowth assay","journal":"The Journal of neuroscience : the official journal of the Society for Neuroscience","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted GAP activity with molecular dissection of activation mechanism, multiple orthogonal functional assays","pmids":["15601954"],"is_preprint":false},{"year":2004,"finding":"Constitutively active R-Ras (38V) decreases Rac activity and increases Rho activity at the cell periphery; dominant-negative R-Ras shows the converse; endogenous R-Ras localizes and is preferentially activated at the leading edge; R-Ras effects on migration are mediated by PI 3-kinase (effector mutant uncoupling PI3K binding rescues migration).","method":"Rho/Rac activity assays (pull-down), localization by immunofluorescence with activity probe, siRNA knockdown, PI3K-uncoupling effector mutant, cell migration assays","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — GTPase activity pull-down assays plus localization imaging plus genetic epistasis with effector mutant; multiple orthogonal methods","pmids":["15525681"],"is_preprint":false},{"year":2005,"finding":"The unique N-terminal 26-amino-acid extension of R-Ras is required for Rac activation and Rac-dependent cell spreading; truncated R-Ras lacking this N-terminus fails to activate Rac and stimulates more β3-integrin-dependent migration; the N-terminus does not affect subcellular localization or cell adhesion.","method":"N-terminal truncation mutants, Rac-GTP pull-down assay, cell spreading assay, migration assay in 32D cells","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — N-terminal deletion mutant plus Rac activation assay and functional readouts, single lab","pmids":["15772154"],"is_preprint":false},{"year":2005,"finding":"EphB2 activates R-Ras, which becomes associated with the receptor and highly phosphorylated; siRNA depletion of R-Ras abrogates EphB2 effects on glioma cell adhesion, proliferation, and invasion, confirming R-Ras as a required downstream mediator of EphB2 in glioma.","method":"siRNA knockdown of R-Ras, EphB2 activation experiments, cell adhesion/invasion assays, R-Ras co-immunoprecipitation with EphB2, phosphorylation analysis","journal":"The American journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown with multiple functional readouts plus co-IP, single lab","pmids":["16049340"],"is_preprint":false},{"year":2006,"finding":"Sema4D/Plexin-B1 suppresses R-Ras activity in hippocampal neurons, leading to dephosphorylation of Akt and activation of GSK-3β; constitutively active Akt or GSK-3 inhibitors block Sema4D-induced growth cone collapse; Plexin-B1 R-Ras GAP activity is required for downstream Akt dephosphorylation, GSK-3β activation, and CRMP-2 phosphorylation.","method":"R-Ras GTPase activity assay, Akt and GSK-3β phosphorylation immunoblotting, pharmacological inhibitors (GSK-3 inhibitors, PI3K activators), siRNA/dominant-negative constructs in hippocampal neurons","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple pharmacological and genetic interventions establishing a linear pathway: Plexin-B1 GAP→R-Ras inactivation→PI3K reduction→Akt dephosphorylation→GSK-3β activation→CRMP-2 phosphorylation","pmids":["16799460"],"is_preprint":false},{"year":2006,"finding":"Sema4D/Plexin-B1 R-Ras GAP activity suppresses β1 integrin activation and cell migration in response to ECM; knockdown or dominant-negative inhibition of R-Ras alone is sufficient to suppress β1 integrin activation and migration, establishing R-Ras as a required mediator between ECM and β1 integrin activation.","method":"R-Ras siRNA knockdown, R-Ras-specific GAP overexpression, β1 integrin activation assay, cell migration assay, PI3K activation assay","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA and overexpression of specific GAP plus β1 integrin activity and migration assays; clean loss-of-function approach","pmids":["16702230"],"is_preprint":false},{"year":2006,"finding":"R-Ras drives membrane protrusion through PLCε: R-Ras co-precipitates with PLCε and increases PLCε activity; siRNA knockdown of PLCε reduces ruffling lamellipod formation; PLC inhibitors and intracellular Ca2+ chelation block R-Ras-mediated membrane protrusions and spreading.","method":"TIRF microscopy, co-immunoprecipitation, PLCε activity assay, siRNA knockdown of PLCε, pharmacological PLC inhibitors, Ca2+ chelation","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus siRNA plus pharmacological validation; multiple methods in single study","pmids":["16537651"],"is_preprint":false},{"year":2006,"finding":"Eph receptors inactivate R-Ras through two mechanisms: (1) phosphorylation at tyrosine 66 via EphB2, and (2) increased GTP hydrolysis through p120RasGAP; retraction of cell periphery depends only on p120RasGAP-mediated inactivation, while ephrin-inhibited migration and growth cone collapse require both mechanisms.","method":"R-Ras mutants resistant to p120RasGAP and/or Y66 phosphorylation, COS cell retraction assay, cell migration assay, growth cone collapse assay in primary neurons","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic mutagenesis dissecting two independent inhibitory mechanisms with distinct functional readouts; clean genetic dissection","pmids":["16522685"],"is_preprint":false},{"year":2006,"finding":"RLIP76 (RalBP1) is a novel R-Ras-specific effector: it binds R-Ras directly in a GTP-dependent manner but not H-Ras or Rap1A; RLIP76 is required for adhesion-induced Rac activation, cell spreading, and migration; RLIP76 regulates Rac through an Arf6 GTPase cascade.","method":"R-Ras interactome database mining, direct binding assay, GTP-dependence test, siRNA knockdown of RLIP76, Rac and Arf6 activity assays, cell spreading/migration assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct GTP-dependent binding plus siRNA with multiple functional readouts; Arf6 pathway epistasis established","pmids":["16966426"],"is_preprint":false},{"year":2006,"finding":"R-Ras activates JNK in 293T and NIH 3T3 cells through the C3G GEF pathway; constitutively active R-Ras (Val-38) activates JNK, whereas dominant-negative R-Ras (Asn-43) inhibits v-Crk-induced JNK activation; R-Ras-mediated JNK activation requires mixed lineage kinase 3 (MLK3).","method":"JNK activity assays, dominant-negative R-Ras expression, v-Crk oncogene transfection, MLK3 dominant-negative inhibition, flat-reversion of transformed NIH 3T3 cells","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with multiple constructs and kinase assays, single lab","pmids":["10777559"],"is_preprint":false},{"year":2006,"finding":"R-Ras controls axon specification in hippocampal neurons: it localizes to the prospective axon, activates PI 3-kinase to recruit ILK to the membrane, and ILK inactivates GSK-3β, leading to axon formation; R-Ras knockdown blocks GSK-3β inactivation and axon formation.","method":"Immunofluorescence localization, R-Ras siRNA knockdown, ILK siRNA knockdown, ILK membrane targeting construct, GSK-3β phosphorylation immunoblotting, axon formation assay in primary hippocampal neurons","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA knockdown at multiple pathway steps (R-Ras, ILK), membrane-targeted ILK rescue, clear epistatic pathway placement in primary neurons","pmids":["17107957"],"is_preprint":false},{"year":2006,"finding":"Cyclic AMP activates R-Ras through Epac (exchange protein directly activated by cAMP) via G protein-coupled receptors; Epac1 directly interacts with R-Ras and catalyzes GDP/GTP exchange in vitro; activated R-Ras specifically mediates GPCR-stimulated phospholipase D activation.","method":"Epac-specific cAMP analog, Epac1 siRNA knockdown, dominant-negative Rap GTPases, in vitro GEF assay (Epac1 + R-Ras), phospholipase D activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro GEF exchange assay plus multiple genetic/pharmacological validations in cells; two independent methods","pmids":["16754664"],"is_preprint":false},{"year":2006,"finding":"R-Ras GAP is transcriptionally downregulated by NGF during PC12 neurite formation, allowing R-Ras activation to promote neurite growth; R-Ras GAP homozygous mutant mice die at E12.5–13.5 from hemorrhage due to underdeveloped adherens junctions in capillary endothelial cells.","method":"Stable R-Ras GAP overexpression in PC12 cells, NGF stimulation, neurite formation assay, R-Ras GAP knockin/knockout mouse generation, embryonic histology","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-based stable overexpression with functional readout plus genetic mouse model with vascular phenotype","pmids":["17179160"],"is_preprint":false},{"year":2007,"finding":"R-Ras is enriched on early and recycling endosomes; endosomal R-Ras activity is higher than at the plasma membrane and correlates with accumulation of the Rgl2/Rlf GEF for RalA, leading to high endosomal RalA activity; R-Ras or RalA shRNA suppresses calcium-triggered exocytosis in PC12 cells.","method":"FRET-based R-Ras activity probe (subcellular), anti-R-Ras antibody localization, shRNA knockdown of R-Ras and RalA, calcium-triggered exocytosis assay in PC12 cells","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live-cell FRET activity imaging plus shRNA functional assay, single lab","pmids":["17344481"],"is_preprint":false},{"year":2007,"finding":"Mammalian Notch-1 intracellular domain (released by γ-secretase cleavage) activates R-Ras and thereby activates β1 integrins, independently of CSL-mediated transcription; Notch-1 reverses H-Ras/Raf-mediated integrin suppression without affecting ERK; Delta-like ligand-4 stimulates R-Ras-dependent α5β1 integrin adhesion.","method":"γ-secretase inhibitor, Notch mutants (inefficient cleavage, ankyrin repeat deletion, PEST domain truncation), R-Ras GTP-loading assay, integrin activation assay, Delta-like ligand-4 stimulation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple Notch mutants plus pharmacological inhibitor plus physiological ligand stimulation; single lab","pmids":["17664272"],"is_preprint":false},{"year":2008,"finding":"Transcription factor 8 (TCF8) activates R-Ras by binding CalDAG-GEFIII (an R-Ras GEF) in the cytosol, not through transcriptional regulation; TCF8-activated R-Ras suppresses endothelial tube formation.","method":"Co-immunoprecipitation of TCF8 and CalDAG-GEFIII, R-Ras GTP-loading assay, siRNA knockdown, tube formation assay in HUVECs","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single co-IP plus limited functional data, single lab, small study","pmids":["19116136"],"is_preprint":false},{"year":2009,"finding":"Plexin-D1 exhibits R-Ras GAP activity requiring Rnd2 (not Rnd1); Sema3E/Plexin-D1 inhibits axon outgrowth of cortical neurons requiring Rnd2 and R-Ras downregulation; Plexin-C1 exhibits R-Ras GAP activity independently of any Rnd protein.","method":"R-Ras GTPase activity assay, co-immunoprecipitation of Rnd2 with Plexin-D1, Rnd2 siRNA, cell migration inhibition assay, cortical neuron axon outgrowth assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro GAP assay plus co-IP plus siRNA functional assays; defines Rnd requirement specificity across plexin subfamily","pmids":["19136556"],"is_preprint":false},{"year":2010,"finding":"Fam38A (Piezo1 precursor) localizes at the ER and recruits R-Ras to the ER, where R-Ras activates calpain by increasing Ca2+ release from ER stores; calpain then cleaves talin to activate β1 integrins; siRNA knockdown of Fam38A, R-Ras, calpain, or talin each block integrin activation.","method":"siRNA knockdown of Fam38A/R-Ras/calpain/talin, Ca2+ release measurement, calpain activity assay, β1 integrin activation assay, subcellular co-localization (confocal)","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA knockdown at four pathway steps plus Ca2+ and calpain assays; defines an ER-based R-Ras signaling mechanism with multiple orthogonal validations","pmids":["20016066"],"is_preprint":false},{"year":2010,"finding":"Sema3E activates Plexin-D1 to inactivate R-Ras and stimulate Arf6, causing disassembly of integrin adhesive structures and inhibition of endothelial cell adhesion; R-Ras inactivation controls integrin activation status while Arf6 stimulation controls integrin intracellular trafficking.","method":"R-Ras GTP-loading assay, Arf6 activation assay, integrin adhesion and fibrillar adhesion assays, dominant-negative R-Ras/Arf6 constructs, endothelial cell retraction assay","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — parallel measurement of R-Ras and Arf6 activities with functional integrin assays, single lab","pmids":["20385769"],"is_preprint":false},{"year":2010,"finding":"Sema4D/Plexin-B1 R-Ras GAP activity promotes dephosphorylation and activation of PTEN (at Ser-380) through inhibition of casein kinase 2α; PTEN activation contributes to growth cone collapse downstream of R-Ras inactivation.","method":"PTEN phosphorylation immunoblotting, PTEN phosphatase activity assay, phospho-mimic/phospho-resistant PTEN mutants, casein kinase 2α activity assay, growth cone collapse assay in hippocampal neurons","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct PTEN phosphatase activity assay plus phospho-mutant epistasis plus CK2 inhibition; clear pathway from R-Ras GAP to PTEN activation","pmids":["20610402"],"is_preprint":false},{"year":2010,"finding":"R-Ras colocalizes with and is endocytosed from membrane ruffles, trafficking via Rab11-positive vesicles; active R-Ras promotes ruffle formation and β1 integrin endocytosis; dominant-negative R-Ras and R-Ras siRNA prevent β1 integrin accumulation in ruffles and impair β1-integrin-mediated adhesion.","method":"GFP-R-Ras live-cell imaging, Rab11 co-localization, siRNA knockdown, β1 integrin endocytosis assay, TIRF microscopy","journal":"BMC cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live-cell imaging plus siRNA functional assays; single lab","pmids":["20167113"],"is_preprint":false},{"year":2010,"finding":"DHHC19 is a palmitoyl transferase that specifically palmitoylates R-Ras (not H-Ras, N-Ras, K-Ras4A, RhoB, or Rap2); DHHC19 co-expression increases R-Ras palmitoylation approximately 2-fold, enhances R-Ras membrane and raft/caveolae association, and increases cell viability.","method":"Palmitoylation assay (metabolic labeling), membrane fractionation, raft/caveolae isolation, co-transfection in COS7 cells, cell viability assay","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct palmitoylation assay with substrate specificity testing across multiple GTPases; single lab","pmids":["20074548"],"is_preprint":false},{"year":2010,"finding":"R-Ras interacts with filamin A (FLNa) via FLNa repeat 3; active R-Ras colocalizes with FLNa and coordinately increases cell migration and fibronectin matrix assembly; siRNA knockdown of endogenous R-Ras impairs FLNa-dependent fibronectin matrix assembly.","method":"Yeast two-hybrid screen, co-immunoprecipitation, GST-FLNa pulldown, FLNaΔ3 deletion mutant, co-localization immunofluorescence, siRNA knockdown, cell migration and fibronectin assembly assays","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus co-IP plus siRNA functional assay; multiple binding methods but single lab","pmids":["20585650"],"is_preprint":false},{"year":2011,"finding":"R-Ras interacts with FLNa (repeat 3) in endothelial cells; co-knockdown of R-Ras and FLNa promotes vascular permeability, disorganizes VE-cadherin at adherens junctions, and increases Src (Y416) and VE-cadherin (Y731) phosphorylation; dominant-negative R-Ras-induced permeability is blocked by Src inhibitor PP2.","method":"Co-immunoprecipitation, FLNaΔ3 rescue experiments, siRNA knockdown, transendothelial electrical resistance, FITC-dextran permeability assay, VE-cadherin immunostaining","journal":"Journal of cellular physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus siRNA knockdown plus FLNaΔ3 rescue defining the R-Ras/FLNa complex in barrier function; single lab","pmids":["21660952"],"is_preprint":false},{"year":2012,"finding":"R-Ras-GTP binds RIN2 (Ras and Rab5 interacting protein) and converts it from a Rab5 GEF to an adaptor that binds Rab5-GTP; this promotes selective endocytosis of ligand-bound/active β1 integrins; the R-Ras/RIN2/Rab5 module then activates Rac1 via TIAM1 on early endosomes to drive endothelial cell adhesion.","method":"Co-immunoprecipitation of R-Ras with RIN2, active integrin endocytosis assay, Rac1 activation assay, TIAM1 localization, RIN2 siRNA, Rab5 GEF activity assay, dominant-negative constructs","journal":"Cell research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods defining the R-Ras→RIN2→Rab5→TIAM1→Rac1 pathway; endocytosis assay plus GTPase assays plus siRNA; single lab but comprehensive","pmids":["22825554"],"is_preprint":false},{"year":2012,"finding":"Palmitoylation of R-Ras is required for exit from the Golgi in post-Golgi vesicle membranes and trafficking to the plasma membrane; geranylgeranylation is required for membrane anchorage; palmitoylation-deficient R-Ras blocks membrane ruffling, PI3K interaction, PtdIns(3,4,5)P3 enrichment at plasma membrane, and R-Ras-dependent cell spreading.","method":"Palmitoylation-deficient mutant analysis, GFP-tagged R-Ras vesicle trafficking by live-cell imaging, Rab11 co-localization, PI3K co-immunoprecipitation, PtdIns(3,4,5)P3 reporter, cell spreading assay","journal":"Small GTPases","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — palmitoylation mutant functional analysis plus live-cell imaging plus PI3K interaction assay; single lab","pmids":["22751447"],"is_preprint":false},{"year":2012,"finding":"R-Ras controls axon branching in cortical neurons through afadin: active R-Ras induces translocation of afadin to membranes via afadin's RA (Ras-association) domains; afadin RA domain and F-actin binding domain are required for axon branching; R-Ras and afadin interact endogenously during axon development.","method":"Co-immunoprecipitation of endogenous R-Ras and afadin, afadin domain deletion mutants, siRNA knockdown of afadin, R-Ras constitutively active expression, subcellular localization analysis in cortical neurons","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — endogenous co-IP plus domain mutant analysis plus siRNA in primary neurons; single lab","pmids":["22593211"],"is_preprint":false},{"year":2014,"finding":"ORP3-hyperphosphorylated form (ORP3-P) selectively interacts with the ER membrane protein VAPA via FFAT-like and canonical FFAT motifs; ORP3-VAPA complexes are targeted to PM sites via the ORP3 PH domain; ORP3-VAPA co-expression induces R-Ras activation and downstream AktS473 phosphorylation and β1 integrin activity.","method":"ORP3 mutagenesis (FFAT motif), co-immunoprecipitation of ORP3-P with VAPA, β1 integrin activity assay, Akt phosphorylation, VAPA co-expression","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — mutant interaction mapping plus R-Ras activation readout; mechanism linking ORP3-VAPA to R-Ras is not fully reconstituted","pmids":["25447204"],"is_preprint":false},{"year":2014,"finding":"SHANK1 and SHANK3 limit integrin activation by sequestering GTP-bound R-Ras (and Rap1) via the SHANK SPN domain (revealed as a Ras-association domain by crystal structure); autism-related SHANK3 SPN mutations (R12C and L68P) disrupt G-protein interaction and fail to inhibit integrin activation along the Rap1-RIAM-talin axis.","method":"Crystal structure of SHANK3 N-terminal region, affinity measurements of SPN-R-Ras interaction, SHANK3 silencing (increased Rap1 activity, cell spreading/migration/invasion), SPN point mutant functional rescue assays in cancer cells and neurons","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus quantitative binding measurements plus functional mutagenesis and siRNA in multiple cell types; multiple orthogonal methods","pmids":["28263956"],"is_preprint":false},{"year":2015,"finding":"R-Ras suppresses internalization/endocytosis of VEGFR2 in endothelial cells, thereby strongly inhibiting VEGF-induced autophosphorylation at all five major tyrosine sites; this suppression is partially dependent on VE-cadherin; silencing R-Ras increases VEGFR2 phosphorylation and R-Ras knockout mice show elevated VEGFR2 phosphorylation in tumor vasculature.","method":"VEGFR2 internalization assay, VEGFR2 phosphorylation immunoblotting (5 sites), R-Ras siRNA, R-Ras knockout mouse tumor model, VE-cadherin knockdown epistasis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — receptor internalization mechanism plus site-specific phosphorylation analysis plus in vivo validation in knockout mice; multiple orthogonal methods","pmids":["25645912"],"is_preprint":false},{"year":2016,"finding":"R-Ras strongly suppresses VEGF-dependent activation of p38MAPK and downstream HSP27 phosphorylation in endothelial cells; silencing R-Ras by siRNA increases VEGF-induced membrane protrusion and migration, effects reversed by p38MAPK inhibitor SB203580, establishing R-Ras as a regulator of the p38MAPK-HSP27 axis.","method":"p38MAPK and HSP27 phosphorylation immunoblotting, R-Ras siRNA, p38MAPK inhibitor SB203580, cell migration assay, membrane protrusion assay","journal":"Journal of vascular research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA plus pharmacological inhibitor rescue in two orthogonal functional assays; single lab","pmids":["27029009"],"is_preprint":false},{"year":2016,"finding":"RASA1 (p120RasGAP) exerts its tumor-suppressive function specifically through its GAP activity toward R-Ras; RASA1 mutants (Y472H, L481F) found in melanoma lack GAP activity toward R-Ras; wild-type RASA1 suppresses soft agar colony formation via R-Ras; R-Ras promotes RalA activation among downstream effectors.","method":"Soft-agar colony formation assay, RASA1 GAP activity assay toward R-Ras, RASA1 point mutant expression, RalA activation assay","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct GAP activity measurement plus functional colony assay with mutants; single lab","pmids":["26993606"],"is_preprint":false},{"year":2017,"finding":"R-Ras-Akt signaling stabilizes the microtubule cytoskeleton in endothelial cells, promoting endothelial lumenogenesis; VEGF-A-activated Akt does not similarly stabilize microtubules or drive lumen formation; R-Ras-Akt pathway is required in vivo for lumenization of new capillaries in ischemic muscle.","method":"R-Ras constitutively active and dominant-negative expression, microtubule stability assay, 3D lumen formation assay, R-Ras knockout mouse ischemia model, Akt inhibitor","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vitro mechanism (microtubule stabilization) validated in vivo with knockout mouse ischemia model; two orthogonal functional readouts","pmids":["29170374"],"is_preprint":false},{"year":2018,"finding":"Prolonged cAMP elevation transcriptionally represses RRAS gene expression in endothelial cells via a CREB3-dependent mechanism, disrupting VE-cadherin at adherens junctions and increasing vascular permeability; cAMP-induced plasma leakage from microvessels in mouse skin is mediated by RRAS repression.","method":"RT-PCR and immunoblotting of R-Ras upon cAMP elevation, CREB3 siRNA, R-Ras rescue transduction, VE-cadherin localization, TEER and FITC-dextran permeability assay, in vivo Miles assay in mice","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — transcriptional mechanism defined via CREB3 siRNA, rescued by R-Ras re-expression; validated in vivo with mouse permeability model","pmids":["29775418"],"is_preprint":false},{"year":2019,"finding":"RasGRP2 (CalDAG-GEF) activates R-Ras (in addition to Rap1) in endothelial cells; the R-Ras-PI3K-Akt signaling pathway activated by RasGRP2 suppresses Bax-activation-induced apoptosis by promoting translocation of hexokinase-2 from cytoplasm to mitochondria.","method":"Rap1 and R-Ras GTP pull-down assays, Rap1 siRNA knockdown, R-Ras siRNA knockdown, Akt phosphorylation, Bax translocation assay, HK-2 localization, apoptosis assay","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — GTPase activation assay plus siRNA epistasis plus HK-2 translocation assay; single lab","pmids":["31723205"],"is_preprint":false},{"year":2022,"finding":"PI3KC2α synthesizes PI(3,4)P2 at focal adhesions, which recruits RASA3 (RasGAP); RASA3 at focal adhesions inactivates R-RAS, increasing focal adhesion turnover, cell migration, and invasion; inhibiting PI3KC2α or lowering RASA3 activity reduces metastasis in PI3KC2α-overexpressing breast cancer models.","method":"PI3KC2α knockdown/overexpression, PI(3,4)P2 localization at focal adhesions, RASA3 co-localization and recruitment assay, R-RAS GTP-loading assay, focal adhesion turnover assay, in vivo metastasis model","journal":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal assays establishing PI3KC2α→PI(3,4)P2→RASA3→R-Ras inactivation axis; single lab but comprehensive in vitro and in vivo data","pmids":["35098698"],"is_preprint":false},{"year":2023,"finding":"FOXF1 directly activates the RRAS gene promoter through transcriptional activation in endothelial cells; endothelial-specific Foxf1 inhibition impairs R-Ras signaling and increases collagen deposition; nanoparticle delivery of Foxf1 cDNA decreases pulmonary fibrosis, with the mechanism involving FOXF1-dependent R-Ras transcription.","method":"Single-cell RNA-sequencing, FOXF1 promoter luciferase/ChIP (implied by 'direct transcriptional activation'), endothelial-specific Foxf1 knockout mouse, R-Ras signaling analysis, nanoparticle Foxf1 delivery in bleomycin mouse model","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic mouse model plus in vivo rescue experiment; RRAS as a direct FOXF1 target supported by promoter analysis, single lab","pmids":["37137915"],"is_preprint":false}],"current_model":"R-Ras is a Ras-family small GTPase that cycles between GDP-bound (inactive) and GTP-bound (active) states regulated by multiple GEFs (RasGRF, C3G, CalDAG-GEFs, Epac1) and GAPs (p120RasGAP, NF1, R-Ras GAP, and plexin receptors acting directly as GAPs); its best-characterized function is the positive regulation of integrin ligand-binding affinity (inside-out signaling) through a PI3K-dependent pathway, with additional distinct effectors including RLIP76, afadin, RIN2, PLCε, and ILK; its activity and localization are modulated by palmitoylation (by DHHC19) and by tyrosine phosphorylation at Y66 by EphB2 and Src (suppressing integrin activation); plexin-B1 and -D1 receptors serve as direct R-Ras GAPs requiring Rnd1/Rnd2 to mediate semaphorin-induced growth cone collapse and repulsive axon guidance via sequential inactivation of PI3K, dephosphorylation of Akt, activation of GSK-3β and PTEN; in the vasculature R-Ras stabilizes endothelial barriers by maintaining VE-cadherin junctions and suppressing VEGFR2 internalization/autophosphorylation, and promotes endothelial lumenogenesis via Akt-dependent microtubule stabilization."},"narrative":{"mechanistic_narrative":"R-Ras (RRAS) is a membrane-anchored Ras-family small GTPase whose principal cellular role is the positive control of integrin ligand-binding affinity and the resulting programs of cell adhesion, spreading, and migration (\"inside-out\" signaling) [PMID:8620538]. It cycles between GDP- and GTP-bound states under the control of a broad set of GEFs — including RasGRF, C3G, the CalDAG-GEF/RasGRP family, Epac1, and AND-34/BCAR3 — and GAPs including p120RasGAP, NF-1, and a dedicated ~98-kDa R-Ras GAP [PMID:8530488, PMID:10777492, PMID:16754664]. Unlike classical Ras, active R-Ras does not drive the Raf–MEK–ERK axis but instead signals through PI 3-kinase to activate Akt, and this PI3K branch is essential for both its transforming activity and its pro-adhesive, pro-survival functions [PMID:8999998, PMID:10454580]. Membrane targeting and effector engagement depend on C-terminal palmitoylation (C213) and geranylgeranylation, which direct Golgi exit, focal-adhesion localization, and productive PI3K coupling [PMID:12890755, PMID:22751447]. Beyond PI3K, GTP-bound R-Ras engages distinct effectors to remodel the cytoskeleton and traffic integrins: RLIP76/RalBP1 and an Arf6 cascade, the proline-rich/Nck adaptor link, PLCε-driven membrane protrusion, and a RIN2→Rab5→TIAM1→Rac1 module that drives endocytosis of active β1 integrins [PMID:10671570, PMID:16537651, PMID:16966426, PMID:22825554]. R-Ras activity is suppressed by tyrosine phosphorylation at Y66 by EphB2 and Src, and by plexin receptors that act as direct R-Ras GAPs: plexin-B1 (with Rnd1), plexin-D1 (with Rnd2), and plexin-C1 (Rnd-independent) inactivate R-Ras in response to semaphorins to mediate growth cone collapse and repulsive guidance through sequential loss of PI3K signaling, Akt dephosphorylation, GSK-3β and PTEN activation [PMID:10570155, PMID:11682467, PMID:15297673, PMID:19136556, PMID:16799460, PMID:20610402]. In the vasculature R-Ras stabilizes endothelial barriers by maintaining VE-cadherin junctions, suppressing VEGFR2 internalization and autophosphorylation, and dampening p38MAPK–HSP27 signaling, and it promotes endothelial lumenogenesis via Akt-dependent microtubule stabilization [PMID:25645912, PMID:27029009, PMID:29170374]; its endothelial expression is set transcriptionally by FOXF1 and repressed by cAMP/CREB3 [PMID:29775418, PMID:37137915].","teleology":[{"year":1987,"claim":"Established R-Ras as a bona fide membrane-associated, lipid-modified GTP-binding protein analogous to H-Ras, defining its biochemical identity.","evidence":"Metabolic [3H]palmitate labeling, membrane fractionation, and GTP-binding/autokinase assays on expressed protein","pmids":["3313005"],"confidence":"High","gaps":["No cellular function assigned","Effectors and regulators unidentified"]},{"year":1989,"claim":"Showed R-Ras GTPase activity is controlled by the canonical 125-kDa rasGAP via its effector domain, placing R-Ras within Ras-family regulatory logic while hinting at lipid-modulated regulation.","evidence":"In vitro GTPase-activating assays with mammalian extracts and defined phospholipids","pmids":["2491843","2513485"],"confidence":"High","gaps":["Physiological GAP not yet identified","Functional consequence of GAP regulation unknown"]},{"year":1993,"claim":"Linked R-Ras to apoptosis regulation by identifying a physical Bcl-2 interaction through its C-terminus, the first effector-type partner.","evidence":"Yeast two-hybrid and co-immunoprecipitation from human cell extracts","pmids":["8232588"],"confidence":"High","gaps":["Functional direction of Bcl-2 interaction not resolved here","GTP-dependence not established"]},{"year":1994,"claim":"Defined R-Ras as a transforming GTPase that engages Raf-1 and RalGDS in a GTP-dependent manner and cooperates with c-raf-1, raising the question of which effectors are physiological.","evidence":"Yeast two-hybrid, in vitro binding with purified proteins, site-directed mutagenesis and NIH3T3 transformation assays","pmids":["8002932","7809086","8108110","8084601"],"confidence":"High","gaps":["Whether Raf/RalGDS binding is physiologically relevant unresolved","No distinct R-Ras-specific effector identified"]},{"year":1995,"claim":"Resolved the apoptosis question by placing Bcl-2 downstream of R-Ras and identified a dedicated R-Ras-specific GAP, distinguishing R-Ras regulation from classical Ras.","evidence":"IL-3-withdrawal apoptosis assays with Bcl-2 epistasis; GST-R-Ras affinity purification and reconstituted GAP assays","pmids":["7744959","8530488"],"confidence":"High","gaps":["Identity/cloning of the R-Ras-specific GAP only partially defined","Apoptosis pathway intermediates between R-Ras and Bcl-2 unclear"]},{"year":1996,"claim":"Identified the defining cellular function of R-Ras — control of integrin ligand-binding affinity (inside-out signaling) — and showed its weak/nonspecific binding to Raf/RalGDS argues against those as primary effectors.","evidence":"Activated/dominant-negative R-Ras with integrin affinity and adhesion assays; quantitative solution binding measurements","pmids":["8620538","8636102"],"confidence":"High","gaps":["Downstream effector for integrin control not yet identified","Mechanism connecting R-Ras to integrin cytoplasmic tail unknown"]},{"year":1997,"claim":"Established PI 3-kinase/Akt as the central R-Ras effector branch, distinguishing it from the Ras-Raf-MAPK axis.","evidence":"Co-transfection PI3K lipid product and PKB/Akt kinase assays with wortmannin","pmids":["8999998"],"confidence":"High","gaps":["Direct vs indirect PI3K activation not fully resolved","Link from PI3K to integrin affinity not yet mapped"]},{"year":1999,"claim":"Showed R-Ras activity is suppressed by EphB2-mediated phosphorylation at Y66 and recruited to EphB2 via SHEP1, defining an anti-adhesive regulatory input, while effector-loop mutagenesis dissociated transformation from adhesion/survival and pinned both PI3K-dependent functions.","evidence":"Y66F mutagenesis with EphB2 activation and adhesion rescue; yeast two-hybrid/co-IP for SHEP1; systematic effector-loop mutants with PI3K/Akt inhibitors","pmids":["10570155","10542222","10454580","10352023","10359597"],"confidence":"High","gaps":["SHEP1 GEF exchange activity on R-Ras not directly demonstrated","How PI3K vs PKC branches diverge for invasion incompletely defined"]},{"year":2000,"claim":"Mapped the regulator landscape of R-Ras (multiple GEFs and GAPs) and identified non-PI3K outputs — a GTP-independent Nck/proline-rich link, cAMP/Epac activation, and JNK/MLK3 and PLD activation — broadening its effector repertoire.","evidence":"In vitro and cell-based GEF/GAP assays; GST-SH3 pulldowns and adhesion mutants; Epac in vitro GEF assay; JNK kinase assays with MLK3 dominant-negatives","pmids":["10777492","10835426","10896938","10671570","16754664","10777559","11134082","10801791"],"confidence":"High","gaps":["Which GEF/GAP pairs operate in which cell context unresolved","Some PI3K-dependence findings conflict across cell types"]},{"year":2001,"claim":"Confirmed R-Ras suppression by Src at Y66 and extended its function to Rap1-dependent phagocytic integrin activation, reinforcing adhesion control over mitogenic output.","evidence":"In vitro and cellular Src kinase assays, Y66F rescue, co-IP; microinjection and macrophage phagocytosis assays","pmids":["11682467","11257001"],"confidence":"High","gaps":["Interplay between Src and EphB2 phosphorylation at Y66 not resolved here","Role of Rap1 vs R-Ras in phagocytosis not separated"]},{"year":2003,"claim":"Defined the membrane-targeting determinants (C-terminal HVR, palmitoylation at C213) required for focal-adhesion localization and showed active R-Ras enhances FAK/p130Cas adhesion signaling; introduced ORP3 as an interacting adhesion regulator.","evidence":"H-Ras/R-Ras chimeras, C213A mutagenesis, fractionation, immunofluorescence; phospho-FAK/p130Cas immunoblotting; co-IP and siRNA of ORP3","pmids":["12890755","12529399","18270267"],"confidence":"High","gaps":["Mechanism by which ORP3 modulates R-Ras unresolved","How palmitoylation gates effector access not yet defined"]},{"year":2004,"claim":"Established plexin receptors as direct R-Ras GAPs requiring Rnd1, revealing the mechanism (intramolecular C1–C2 release, ligand-induced clustering) and a neuronal function in semaphorin-induced growth cone collapse; in parallel, defined R-Ras leading-edge control of Rac/Rho balance via PI3K.","evidence":"Reconstituted R-Ras GAP assays, domain dissection, antibody-induced clustering, growth cone collapse in hippocampal neurons; Rho/Rac pull-downs with activity imaging and effector mutants","pmids":["15297673","15601954","15525681"],"confidence":"High","gaps":["Direct R-Ras effectors mediating Rac/Rho balance not all identified","Whether plexin GAP activity operates outside neurons not addressed"]},{"year":2005,"claim":"Identified the unique N-terminal extension as required for Rac activation and showed R-Ras as a required downstream mediator of EphB2 in glioma, connecting receptor signaling to invasive behavior.","evidence":"N-terminal truncation mutants with Rac pull-downs; R-Ras siRNA with glioma adhesion/invasion assays and EphB2 co-IP","pmids":["15772154","16049340"],"confidence":"Medium","gaps":["Effector coupling N-terminus to Rac unidentified","How R-Ras both promotes and is inhibited downstream of Eph reconciled"]},{"year":2006,"claim":"Established a coherent semaphorin/plexin→R-Ras-off pathway (PI3K loss→Akt dephosphorylation→GSK-3β→CRMP-2; β1 integrin suppression), defined dual Eph inactivation (Y66 + p120RasGAP), and identified R-Ras-specific effectors RLIP76 and PLCε plus endosomal RalA signaling and axon-specification via ILK.","evidence":"Plexin-B1 GAP assays with Akt/GSK-3β/PTEN readouts; Eph mutant dissection; direct GTP-dependent RLIP76 binding with Arf6 epistasis; PLCε co-IP/siRNA; FRET endosomal activity imaging; ILK siRNA and rescue in primary neurons","pmids":["16799460","16702230","16522685","16966426","16537651","17107957","17344481"],"confidence":"High","gaps":["How a single GTPase coordinates opposing migratory outputs across cell types unresolved","Quantitative effector partitioning (RLIP76 vs PLCε vs PI3K) undefined"]},{"year":2007,"claim":"Showed RalGDS-family effector RalA acts downstream on endosomes for exocytosis, and that Notch-1 intracellular domain activates R-Ras to drive β1 integrin adhesion independently of CSL transcription, expanding upstream activators.","evidence":"FRET activity probes and shRNA exocytosis assays; γ-secretase inhibitors, Notch mutants and R-Ras GTP-loading with integrin assays","pmids":["17344481","17664272"],"confidence":"Medium","gaps":["GEF coupling Notch to R-Ras not identified","Direct vs indirect Notch–R-Ras link unresolved"]},{"year":2010,"claim":"Defined an ER-based activation mechanism (Fam38A/Piezo1→R-Ras→Ca2+/calpain→talin cleavage→β1 integrin), the DHHC19 palmitoyltransferase as R-Ras-specific, plexin-D1/Rnd2 GAP activity, and endosomal trafficking of active integrins via Rab11.","evidence":"Four-step siRNA epistasis with Ca2+/calpain assays; substrate-specific palmitoylation assays; plexin-D1/Rnd2 GAP and co-IP; live-cell imaging and integrin endocytosis assays","pmids":["20016066","20074548","20385769","20167113","20610402","19136556"],"confidence":"High","gaps":["How ER-localized R-Ras integrates with plasma-membrane pool unclear","Plexin subfamily Rnd-requirement logic only partially explained"]},{"year":2012,"claim":"Defined the R-Ras→RIN2→Rab5→TIAM1→Rac1 module coupling active-integrin endocytosis to endothelial adhesion, and identified afadin as the effector for R-Ras-controlled axon branching, mechanistically integrating trafficking and cytoskeletal outputs.","evidence":"Co-IP, integrin endocytosis and Rab5 GEF assays, Rac1 activation, siRNA; endogenous R-Ras/afadin co-IP and domain mutants in cortical neurons","pmids":["22825554","22593211"],"confidence":"High","gaps":["How R-Ras switches RIN2 from GEF to adaptor structurally undefined","Generality of afadin pathway beyond cortical neurons untested"]},{"year":2011,"claim":"Identified the R-Ras/filamin A complex as a regulator of fibronectin matrix assembly and endothelial barrier integrity, mechanistically linking R-Ras to VE-cadherin junction stability and Src restraint.","evidence":"Yeast two-hybrid/co-IP/GST pulldowns with FLNa repeat-3 mutants; siRNA with permeability (TEER, FITC-dextran) and VE-cadherin/Src phospho-analysis","pmids":["20585650","21660952"],"confidence":"Medium","gaps":["Whether FLNa binding is GTP-dependent not established","Mechanism by which R-Ras restrains Src at junctions unclear"]},{"year":2015,"claim":"Defined R-Ras as a suppressor of VEGFR2 endocytosis and autophosphorylation in endothelium, providing a junction-stabilizing, anti-permeability mechanism validated in knockout mice.","evidence":"VEGFR2 internalization and five-site phospho-analysis, R-Ras siRNA, VE-cadherin epistasis, R-Ras knockout tumor vasculature","pmids":["25645912"],"confidence":"High","gaps":["Direct effector mediating VEGFR2 trafficking suppression unidentified","Relationship to RIN2/Rab5 endocytic module unresolved"]},{"year":2016,"claim":"Extended endothelial R-Ras control to the VEGF→p38MAPK–HSP27 axis, showing R-Ras dampens migration-promoting signaling, and showed RASA1/p120RasGAP tumor suppression operates specifically through R-Ras GAP activity.","evidence":"p38/HSP27 phospho-immunoblotting with SB203580 rescue; RASA1 GAP assays and melanoma-mutant colony formation with RalA readout","pmids":["27029009","26993606"],"confidence":"Medium","gaps":["Mechanistic link from R-Ras to p38 not defined","How RASA1 mutations select for R-Ras hyperactivity in tumors unclear"]},{"year":2017,"claim":"Showed R-Ras–Akt signaling stabilizes microtubules to drive endothelial lumenogenesis, a function distinct from VEGF-Akt, validated in vivo, sharpening the role of the PI3K–Akt branch in vascular morphogenesis.","evidence":"Constitutively active/dominant-negative R-Ras, microtubule stability and 3D lumen assays, Akt inhibition, knockout-mouse ischemia model","pmids":["29170374"],"confidence":"High","gaps":["Microtubule-binding effector downstream of Akt unidentified","Why VEGF-Akt fails to phenocopy R-Ras-Akt undefined"]},{"year":2014,"claim":"Provided structural definition of GTP-bound R-Ras sequestration by SHANK SPN domains, with autism-related mutations disrupting the interaction, linking R-Ras to integrin restraint and neurological disease.","evidence":"Crystal structure of SHANK3 N-terminus, affinity measurements, SHANK silencing and SPN point-mutant functional assays; ORP3-P/VAPA interaction mapping with R-Ras activation","pmids":["28263956","25447204"],"confidence":"High","gaps":["Whether SHANK sequestration operates physiologically in neurons in vivo not established","ORP3-VAPA to R-Ras activation mechanism not reconstituted"]},{"year":2019,"claim":"Connected the CalDAG-GEF RasGRP2 to endothelial R-Ras–PI3K–Akt anti-apoptotic signaling acting through hexokinase-2 mitochondrial translocation, extending R-Ras survival functions into the vasculature.","evidence":"Rap1/R-Ras pull-downs, siRNA epistasis, Akt/Bax/HK-2 localization and apoptosis assays","pmids":["31723205"],"confidence":"Medium","gaps":["Relative contributions of Rap1 vs R-Ras not fully separated","Mechanism linking Akt to HK-2 translocation undefined"]},{"year":2022,"claim":"Defined a focal-adhesion lipid–GAP circuit (PI3KC2α→PI(3,4)P2→RASA3→R-Ras-off) controlling adhesion turnover and metastasis, providing a spatially localized inactivation mechanism.","evidence":"PI3KC2α knockdown/overexpression, PI(3,4)P2 and RASA3 localization, R-Ras GTP-loading, focal-adhesion turnover and in vivo metastasis assays","pmids":["35098698"],"confidence":"Medium","gaps":["Generality across cancer types untested","How RASA3 selectivity for R-Ras is achieved unclear"]},{"year":2023,"claim":"Established FOXF1 as a direct transcriptional activator of RRAS in endothelium and showed cAMP/CREB3 represses RRAS, identifying transcriptional control as a determinant of endothelial R-Ras-dependent barrier function and fibrosis.","evidence":"scRNA-seq, promoter analysis, endothelial Foxf1 knockout and nanoparticle rescue; cAMP/CREB3 siRNA with permeability and Miles assays","pmids":["37137915","29775418"],"confidence":"High","gaps":["Direct FOXF1 promoter occupancy details limited","How transcriptional and post-translational regulation are integrated unknown"]},{"year":null,"claim":"The structural basis by which R-Ras partitions among its many effectors (PI3K, RLIP76, PLCε, RIN2, afadin, RalGDS/RalA) in a given subcellular compartment, and how palmitoylation/phosphorylation and localized GAPs choreograph context-specific output, remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of R-Ras effector selection","Quantitative effector partitioning across compartments undefined","In vivo essentiality of individual effector branches untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003924","term_label":"GTPase activity","supporting_discovery_ids":[1,8,18,30,47]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[10,12]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[59]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,28,56]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[28,56]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[44,51,55]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[48,58]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[10,12,30,35]},{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[10,15,53]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[30,41,47,57,63]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[9,65]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[51,55,60]}],"complexes":[],"partners":["RASA1","RAF1","RALGDS","RLIP76","RIN2","FLNA","PLCE1","MRAS-GAP"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P10301","full_name":"Ras-related protein R-Ras","aliases":["p23"],"length_aa":218,"mass_kda":23.5,"function":"GTP-binding protein with GTPase activity, likely involved in the regulation of MAPK signaling pathway and thereby controlling multiple cellular processes (PubMed:39809765). 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 \"discoveries\": [\n    {\n      \"year\": 1987,\n      \"finding\": \"R-Ras p23 protein is palmitoylated (3H-palmitate labeling) and associates with the P100 membrane fraction; it exhibits GTP-binding activity analogous to H-Ras p21, and a threonine 85 substitution mutant undergoes GTP-dependent phosphorylation (autokinase activity analogous to H-Ras T59 mutants).\",\n      \"method\": \"Immunoprecipitation, metabolic labeling with [3H]palmitate, membrane fractionation, GTP-dependent phosphorylation assay in E. coli-expressed protein\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct biochemical assays with purified/expressed protein and multiple orthogonal methods in the original characterization paper\",\n      \"pmids\": [\"3313005\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"R-Ras (p23) interacts with the same 125-kDa rasGAP protein as p21ras (not with the 29-kDa rhoGAP), demonstrating that R-Ras GTPase activity is stimulated by the canonical rasGAP in a manner dependent on the effector domain.\",\n      \"method\": \"GTPase-activating assay using mammalian cytoplasmic extracts, GTPase activity measurements\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro GTPase assay directly measuring GAP activity, replicated across multiple Ras family members as controls\",\n      \"pmids\": [\"2491843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"Certain phospholipids inhibit the interaction between R-Ras and its GTPase-activating protein (GAP), with inhibitory lipids differing from those blocking ras-GAP interaction, suggesting lipid-mediated regulation of R-Ras GAP interaction.\",\n      \"method\": \"In vitro GTPase-activating assay with defined lipids added\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro biochemical assay, single lab, single method\",\n      \"pmids\": [\"2513485\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Bcl-2 physically associates with R-Ras p23; the C-terminal 60 amino acids of R-Ras are sufficient for this interaction, which was detected by yeast two-hybrid and co-immunoprecipitation from human cell extracts.\",\n      \"method\": \"Yeast two-hybrid screen, co-immunoprecipitation from human cell extracts\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal yeast two-hybrid plus co-IP from endogenous cellular extracts, two orthogonal methods in one study\",\n      \"pmids\": [\"8232588\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"R-Ras directly interacts with Raf-1 in a GTP-dependent manner; this interaction requires the N-terminal regulatory domain (aa 1–256) of Raf-1 and the effector domain of R-Ras, as demonstrated by yeast two-hybrid and direct in vitro binding with purified proteins.\",\n      \"method\": \"Yeast two-hybrid, in vitro binding assay with purified R-Ras and Raf-1 Ras-binding domain (aa 51–131)\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro reconstitution with purified proteins plus yeast two-hybrid, two orthogonal methods\",\n      \"pmids\": [\"8002932\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"R-Ras interacts with RalGDS (Ral guanine nucleotide dissociation stimulator) in a GTP-dependent manner via the RalGDS Ras-binding domain (RBD), identified by yeast two-hybrid screening; direct GTP-dependent interaction confirmed with purified proteins in vitro; RalGDS-RBD and Raf-1 RBD compete for binding to R-Ras.\",\n      \"method\": \"Yeast two-hybrid library screen, in vitro binding assay with purified proteins\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — yeast two-hybrid plus reconstituted in vitro binding with purified proteins, two orthogonal methods\",\n      \"pmids\": [\"7809086\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"R-Ras interacts with the catalytic domain of rasGAP and with the GAP-related domain of neurofibromin in vitro, and stimulates c-fos expression when microinjected into Swiss 3T3 cells, but unlike Ras does not induce DNA synthesis, membrane ruffling, oocyte maturation, or PC12 differentiation.\",\n      \"method\": \"In vitro binding assays, microinjection into fibroblasts, gene expression assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro binding plus cell microinjection with defined readouts, two methods in one study\",\n      \"pmids\": [\"8108110\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Oncogenic activation of R-Ras by point mutations at codon 38 (analogous to Ras codon 12) or codon 87 (analogous to codon 61) confers transforming capacity; R-Ras cooperates with c-raf-1 in NIH3T3 transformation, suggesting interaction with the Raf signaling pathway.\",\n      \"method\": \"Site-directed mutagenesis, NIH3T3 focus formation assay, soft-agar colony assay, in vivo tumor assay, co-transfection with c-raf-1\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple functional assays (focus formation, soft agar, tumorigenicity) plus genetic epistasis with c-raf-1, well-replicated activation mechanism\",\n      \"pmids\": [\"8084601\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"A novel ~98-kDa R-Ras-specific GTPase-activating protein (R-Ras GAP) was purified from bovine brain; it binds GTP-bound R-Ras but not GDP-R-Ras, effector-domain-mutant R-Ras, Ha-Ras, or RalA; its GAP-related domain stimulates GTPase activity of R-Ras and weakly of Ha-Ras, but not Rap1 or Rho.\",\n      \"method\": \"GST-R-Ras affinity chromatography, GTPase activity assay with recombinant GAP domain, protein purification and cDNA cloning\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstituted in vitro GAP activity assay with purified proteins and domain mutagenesis, two orthogonal methods\",\n      \"pmids\": [\"8530488\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Activated R-Ras (38V) promotes apoptosis upon growth factor withdrawal via a Bcl-2-suppressible mechanism; Bcl-2 does not alter R-Ras GTP/GDP ratio or inhibit R-Ras-mediated Raf-1 activation, placing Bcl-2 downstream of R-Ras in the cell death pathway.\",\n      \"method\": \"Stable transfection of R-Ras(38V), IL-3 withdrawal apoptosis assay, co-transfection with Bcl-2, in vitro GTPase assay, Raf-1 kinase assay in Sf9 cells\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (cell death assays, GTPase assay, Raf kinase assay, baculovirus co-expression), clear epistatic placement of Bcl-2 downstream of R-Ras\",\n      \"pmids\": [\"7744959\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Expression of constitutively active R-Ras increases integrin ligand-binding affinity without changing integrin surface expression; dominant-negative R-Ras reduces adhesion of endogenous cells, establishing R-Ras as a regulator of integrin activation (inside-out signaling).\",\n      \"method\": \"Stable transfection of activated/dominant-negative R-Ras mutants, integrin ligand-binding affinity assays, cell adhesion assays, fibronectin matrix assembly assay\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — gain- and loss-of-function with multiple functional readouts; foundational paper, widely replicated\",\n      \"pmids\": [\"8620538\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"R-Ras binds to the Raf-1 RBD and RalGDS RBD with weak affinity and no specificity compared to H-Ras/Raf or Rap1A/RalGDS interactions; biochemical solution binding assays show Rap1A, not R-Ras, is the likely physiological effector of RalGDS.\",\n      \"method\": \"Solution binding assays (quantitative affinity measurements), guanine nucleotide dissociation inhibition assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — quantitative in vitro binding with purified proteins, kinetic measurements, multiple Ras family members compared\",\n      \"pmids\": [\"8636102\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"R-Ras activates PI 3-kinase in vitro and elevates PI 3-kinase lipid products in cells, and activates PKB/Akt through a PI 3-kinase-dependent mechanism; unlike Ras, R-Ras does not activate Raf or MAP kinase in cells.\",\n      \"method\": \"Co-transfection assays, PI 3-kinase lipid product measurements, PKB/Akt kinase assays, MAP kinase assays, PI 3-kinase inhibitor (wortmannin)\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple kinase assays, inhibitor validation, PI3K lipid measurements; independently replicated across multiple studies\",\n      \"pmids\": [\"8999998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"EphB2 receptor tyrosine kinase phosphorylates tyrosine 66 in the R-Ras effector domain upon activation, reducing integrin activity and cell adhesion; an R-Ras Y66F mutant resistant to phosphorylation renders cells unresponsive to EphB2-mediated anti-adhesion.\",\n      \"method\": \"EphB2 activation assays, phosphorylation mapping by site-directed mutagenesis (Y66F), cell adhesion assays, transfection rescue experiments\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — phosphorylation site identified by mutagenesis, functional rescue experiment confirms causal relationship\",\n      \"pmids\": [\"10570155\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"SHEP1 (SH2 domain-containing Eph receptor-binding protein 1) directly links activated EphB2 to R-Ras: SHEP1's SH2 domain binds the phosphorylated juxtamembrane region of EphB2, and SHEP1's Ras-GEF-like domain binds R-Ras and Rap1A (but not Ha-Ras or RalA).\",\n      \"method\": \"Yeast two-hybrid screen, co-immunoprecipitation, domain-mapping experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — yeast two-hybrid plus co-IP, two methods but no direct GEF exchange assay performed\",\n      \"pmids\": [\"10542222\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Activated R-Ras (38V) and TC21 promote integrin-mediated migration and invasion of breast epithelial cells through integrin alpha2 (but not alpha5) cytoplasmic domain-dependent signaling, via a combination of PI 3-kinase and PKC (but not MAPK) pathways.\",\n      \"method\": \"Stable transfection, integrin cytoplasmic domain chimeras, cell migration and invasion assays, pharmacological pathway inhibitors\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — integrin chimera specificity assay plus pharmacological dissection, multiple readouts in one study\",\n      \"pmids\": [\"10352023\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"GTP-bound R-Ras antagonizes the Ras/Raf-initiated integrin suppression pathway without competing for common downstream effectors or inhibiting Ras/Raf-induced MAP kinase activation, suggesting distinct downstream effectors.\",\n      \"method\": \"CHO cell transfection, integrin affinity assays, MAP kinase activation assays, dominant-negative/constitutively active mutant expression\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — clean cell-based epistasis, single lab, single main method\",\n      \"pmids\": [\"10359597\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"R-Ras effector domain mutants (S61, G63, C66) dissociate transforming activity from cell adhesion/survival promotion; PI 3-kinase (but not MEK-dependent MAPK) is essential for R-Ras oncogenicity; Akt inhibition blocks R-Ras pro-survival effects; dominant-negative Rac and Ral suppress R-Ras-induced cell adhesion.\",\n      \"method\": \"Effector loop mutagenesis, transformation assays, dominant-negative kinase co-expression, PI3K inhibitor LY294002, cell adhesion/survival assays in 32D cells\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic effector loop mutagenesis plus pharmacological and genetic dissection across multiple biological readouts\",\n      \"pmids\": [\"10454580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"R-Ras guanine nucleotide exchange is promoted by RasGRF, C3G, CalDAG-GEFI, CalDAG-GEFII (RasGRP), and CalDAG-GEFIII both in 293T cells and in vitro; R-Ras GTPase activity is stimulated by Gap1(m), p120 GAP, NF-1, and R-Ras GAP (but not by exchange factors or GAPs for classical Ras exclusively).\",\n      \"method\": \"GTP/GDP ratio measurements in 293T cells, in vitro GEF assays, GAP activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro biochemical GEF and GAP assays plus cell-based measurements, systematic comparison of multiple regulators\",\n      \"pmids\": [\"10777492\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"CalDAG-GEFIII (also called CalDAG-GEFIII) promotes guanine nucleotide exchange on R-Ras (as well as Ha-Ras and Rap1) both in 293T cells and in vitro, demonstrating that R-Ras is a substrate of this calcium/DAG-regulated GEF.\",\n      \"method\": \"GTP/GDP ratio assay in 293T cells, in vitro GEF assay with purified proteins\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstituted exchange assay plus cell-based measurement, two methods\",\n      \"pmids\": [\"10835426\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"AND-34 (BCAR3 homolog) exhibits GEF activity on R-Ras (as well as RalA and Rap1A) in cells; its GEF activity is regulated by binding to p130Cas, with overexpression of p130Cas inhibiting AND-34's Ral GEF activity.\",\n      \"method\": \"GTP/GDP exchange assay in cells, co-immunoprecipitation, dominant-negative construct co-expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — cell-based GEF assay plus co-IP, single lab, limited in vitro validation\",\n      \"pmids\": [\"10896938\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Activated R-Ras, PI 3-kinase, PKCε, and Rac1 can each restore cell spreading inhibited by tac-β1 dominant-negative integrin; R-Ras-mediated rescue of cell spreading requires intact integrin β cytoplasmic domains and PI 3-kinase activity (blocked by LY294002), placing R-Ras upstream of PI 3-kinase in integrin-dependent spreading.\",\n      \"method\": \"Tac-β1 dominant-negative expression, PI 3-kinase inhibitor LY294002, cell spreading area measurements, co-expression of signaling mutants\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic rescue epistasis with pharmacological inhibitor validation, multiple constructs tested\",\n      \"pmids\": [\"11134082\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Ha-Ras activates α5β1 integrin via PI 3-kinase p110δ, while R-Ras activates α5β1 via a distinct PI 3-kinase-independent pathway; R-Ras effector loop mutations affecting cell adhesion do not correlate with PI3K activity.\",\n      \"method\": \"Integrin adhesion assays in mast cells, wortmannin inhibition, effector loop mutants, PI3K co-immunoprecipitation, Akt phosphorylation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — comparative mutant analysis plus pharmacological inhibition, single lab\",\n      \"pmids\": [\"10801791\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"R-Ras contains a proline-rich motif that binds the second SH3 domain of the adaptor protein Nck in a GTP-independent manner; mutations in this proline-rich site suppress R-Ras-mediated cell adhesion without affecting GTP binding.\",\n      \"method\": \"GST-SH3 pulldown, yeast two-hybrid, co-immunoprecipitation from transfected cells, site-directed mutagenesis, cell adhesion assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal binding methods plus functional mutagenesis with adhesion readout\",\n      \"pmids\": [\"10671570\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"R-Ras activates Rap1-dependent αMβ2 integrin-mediated phagocytosis in macrophages but does not activate ERK, JNK, or p38 MAPK pathways; microinjection of activated R-Ras into PC12 cells induces cell spreading rather than differentiation.\",\n      \"method\": \"Microinjection of constitutively active R-Ras into fibroblasts and PC12 cells, phagocytosis assay in macrophage cell line, MAP kinase assays\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — microinjection with defined functional readouts, multiple cell types tested, single lab\",\n      \"pmids\": [\"11257001\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Activated Src kinase (v-Src and Src527) phosphorylates R-Ras at tyrosine 66 in vitro and in cells, suppressing integrin activity; R-Ras and Src co-immunoprecipitate in temperature-sensitive v-Src cells at the permissive temperature; R-Ras Y66F mutant confers partial resistance to Src-mediated loss of adhesion.\",\n      \"method\": \"In vitro kinase assay, endogenous R-Ras phosphorylation in Src-transformed cells, co-immunoprecipitation, site-directed mutagenesis (Y66F), cell adhesion assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro kinase assay plus cell-based phosphorylation, co-IP, and functional mutagenesis rescue; multiple orthogonal methods\",\n      \"pmids\": [\"11682467\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Toxin B variants from toxin A-negative C. difficile strains glucosylate R-Ras (a post-translational modification), causing cell detachment from ECM and blocking EGF-mediated ERK phosphorylation; constitutively active R-Ras expression protects cells against cytopathic effect, confirming R-Ras as the functional target.\",\n      \"method\": \"Glucosylation assay, constitutively active R-Ras rescue transfection, cell adhesion/detachment assay, ERK phosphorylation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct biochemical glucosylation assay plus genetic rescue with constitutively active R-Ras, multiple functional readouts\",\n      \"pmids\": [\"12496290\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Activated R-Ras promotes focal adhesion formation and dramatically enhances FAK and p130Cas phosphorylation upon collagen stimulation or α2β1 integrin clustering; this signaling is partially PI 3-kinase dependent but Src-independent and distinct from canonical integrin signaling.\",\n      \"method\": \"Stable transfection of R-Ras(38V), phospho-FAK and p130Cas immunoblotting, Src and PI3K inhibitors, integrin clustering experiments\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological and genetic pathway dissection with multiple signaling readouts, single lab\",\n      \"pmids\": [\"12529399\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The C-terminal hypervariable region (aa 175–218) of R-Ras contains a focal adhesion targeting signal; palmitoylation at C213 is required for Golgi exit and plasma membrane targeting; activated R-Ras (but not dominant-negative R-Ras) localizes to focal adhesions in a GTP-dependent manner.\",\n      \"method\": \"H-Ras/R-Ras chimera analysis, palmitoylation site mutagenesis (C213A), subcellular fractionation, immunofluorescence localization\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic chimera analysis plus palmitoylation mutagenesis, defining the targeting sequence and lipid modification requirement with functional consequences\",\n      \"pmids\": [\"12890755\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"ORP3 (OSBP-related protein 3) interacts with R-Ras; siRNA knockdown of ORP3 phenocopies constitutively active R-Ras (enhanced β1 integrin activity, altered actin); ORP3 overexpression reduces β1 integrin activity; ORP3 is phosphorylated when cells lose adhesive contacts.\",\n      \"method\": \"Co-immunoprecipitation, siRNA knockdown, β1 integrin activity assay (FACS), phagocytosis assay, actin cytoskeleton analysis\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP binding plus siRNA phenocopy experiments, multiple readouts, single lab\",\n      \"pmids\": [\"18270267\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Plexin-B1 directly stimulates the intrinsic GTPase activity of R-Ras; this GAP activity requires the interaction of Plexin-B1 with Rnd1 (a Rho-family GTPase); R-Ras inactivation by the Plexin-B1–Rnd1 complex is essential for Sema4D-induced growth cone collapse in hippocampal neurons.\",\n      \"method\": \"R-Ras GTPase activity assay (GAP assay), co-immunoprecipitation of Plexin-B1 and Rnd1, Sema4D-induced growth cone collapse assay in primary hippocampal neurons, dominant-negative constructs\",\n      \"journal\": \"Science (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro GAP assay plus co-IP and primary neuron functional assay; foundational mechanistic study widely replicated\",\n      \"pmids\": [\"15297673\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"The Plexin-B1 cytoplasmic domain contains C1 and C2 R-Ras GAP-homologous domains; Rnd1 disrupts an intramolecular C1–C2 interaction to open the GAP domains; Sema4D-induced receptor clustering activates R-Ras GAP activity; deletion of the extracellular domain causes ligand-independent clustering and constitutive R-Ras GAP activity.\",\n      \"method\": \"Domain deletion and mutagenesis of Plexin-B1, antibody-induced clustering of recombinant cytoplasmic domain, R-Ras GTPase activation assay, COS-7 cell contraction assay, hippocampal neurite outgrowth assay\",\n      \"journal\": \"The Journal of neuroscience : the official journal of the Society for Neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted GAP activity with molecular dissection of activation mechanism, multiple orthogonal functional assays\",\n      \"pmids\": [\"15601954\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Constitutively active R-Ras (38V) decreases Rac activity and increases Rho activity at the cell periphery; dominant-negative R-Ras shows the converse; endogenous R-Ras localizes and is preferentially activated at the leading edge; R-Ras effects on migration are mediated by PI 3-kinase (effector mutant uncoupling PI3K binding rescues migration).\",\n      \"method\": \"Rho/Rac activity assays (pull-down), localization by immunofluorescence with activity probe, siRNA knockdown, PI3K-uncoupling effector mutant, cell migration assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — GTPase activity pull-down assays plus localization imaging plus genetic epistasis with effector mutant; multiple orthogonal methods\",\n      \"pmids\": [\"15525681\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"The unique N-terminal 26-amino-acid extension of R-Ras is required for Rac activation and Rac-dependent cell spreading; truncated R-Ras lacking this N-terminus fails to activate Rac and stimulates more β3-integrin-dependent migration; the N-terminus does not affect subcellular localization or cell adhesion.\",\n      \"method\": \"N-terminal truncation mutants, Rac-GTP pull-down assay, cell spreading assay, migration assay in 32D cells\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — N-terminal deletion mutant plus Rac activation assay and functional readouts, single lab\",\n      \"pmids\": [\"15772154\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"EphB2 activates R-Ras, which becomes associated with the receptor and highly phosphorylated; siRNA depletion of R-Ras abrogates EphB2 effects on glioma cell adhesion, proliferation, and invasion, confirming R-Ras as a required downstream mediator of EphB2 in glioma.\",\n      \"method\": \"siRNA knockdown of R-Ras, EphB2 activation experiments, cell adhesion/invasion assays, R-Ras co-immunoprecipitation with EphB2, phosphorylation analysis\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown with multiple functional readouts plus co-IP, single lab\",\n      \"pmids\": [\"16049340\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Sema4D/Plexin-B1 suppresses R-Ras activity in hippocampal neurons, leading to dephosphorylation of Akt and activation of GSK-3β; constitutively active Akt or GSK-3 inhibitors block Sema4D-induced growth cone collapse; Plexin-B1 R-Ras GAP activity is required for downstream Akt dephosphorylation, GSK-3β activation, and CRMP-2 phosphorylation.\",\n      \"method\": \"R-Ras GTPase activity assay, Akt and GSK-3β phosphorylation immunoblotting, pharmacological inhibitors (GSK-3 inhibitors, PI3K activators), siRNA/dominant-negative constructs in hippocampal neurons\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple pharmacological and genetic interventions establishing a linear pathway: Plexin-B1 GAP→R-Ras inactivation→PI3K reduction→Akt dephosphorylation→GSK-3β activation→CRMP-2 phosphorylation\",\n      \"pmids\": [\"16799460\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Sema4D/Plexin-B1 R-Ras GAP activity suppresses β1 integrin activation and cell migration in response to ECM; knockdown or dominant-negative inhibition of R-Ras alone is sufficient to suppress β1 integrin activation and migration, establishing R-Ras as a required mediator between ECM and β1 integrin activation.\",\n      \"method\": \"R-Ras siRNA knockdown, R-Ras-specific GAP overexpression, β1 integrin activation assay, cell migration assay, PI3K activation assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA and overexpression of specific GAP plus β1 integrin activity and migration assays; clean loss-of-function approach\",\n      \"pmids\": [\"16702230\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"R-Ras drives membrane protrusion through PLCε: R-Ras co-precipitates with PLCε and increases PLCε activity; siRNA knockdown of PLCε reduces ruffling lamellipod formation; PLC inhibitors and intracellular Ca2+ chelation block R-Ras-mediated membrane protrusions and spreading.\",\n      \"method\": \"TIRF microscopy, co-immunoprecipitation, PLCε activity assay, siRNA knockdown of PLCε, pharmacological PLC inhibitors, Ca2+ chelation\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus siRNA plus pharmacological validation; multiple methods in single study\",\n      \"pmids\": [\"16537651\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Eph receptors inactivate R-Ras through two mechanisms: (1) phosphorylation at tyrosine 66 via EphB2, and (2) increased GTP hydrolysis through p120RasGAP; retraction of cell periphery depends only on p120RasGAP-mediated inactivation, while ephrin-inhibited migration and growth cone collapse require both mechanisms.\",\n      \"method\": \"R-Ras mutants resistant to p120RasGAP and/or Y66 phosphorylation, COS cell retraction assay, cell migration assay, growth cone collapse assay in primary neurons\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic mutagenesis dissecting two independent inhibitory mechanisms with distinct functional readouts; clean genetic dissection\",\n      \"pmids\": [\"16522685\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"RLIP76 (RalBP1) is a novel R-Ras-specific effector: it binds R-Ras directly in a GTP-dependent manner but not H-Ras or Rap1A; RLIP76 is required for adhesion-induced Rac activation, cell spreading, and migration; RLIP76 regulates Rac through an Arf6 GTPase cascade.\",\n      \"method\": \"R-Ras interactome database mining, direct binding assay, GTP-dependence test, siRNA knockdown of RLIP76, Rac and Arf6 activity assays, cell spreading/migration assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct GTP-dependent binding plus siRNA with multiple functional readouts; Arf6 pathway epistasis established\",\n      \"pmids\": [\"16966426\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"R-Ras activates JNK in 293T and NIH 3T3 cells through the C3G GEF pathway; constitutively active R-Ras (Val-38) activates JNK, whereas dominant-negative R-Ras (Asn-43) inhibits v-Crk-induced JNK activation; R-Ras-mediated JNK activation requires mixed lineage kinase 3 (MLK3).\",\n      \"method\": \"JNK activity assays, dominant-negative R-Ras expression, v-Crk oncogene transfection, MLK3 dominant-negative inhibition, flat-reversion of transformed NIH 3T3 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with multiple constructs and kinase assays, single lab\",\n      \"pmids\": [\"10777559\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"R-Ras controls axon specification in hippocampal neurons: it localizes to the prospective axon, activates PI 3-kinase to recruit ILK to the membrane, and ILK inactivates GSK-3β, leading to axon formation; R-Ras knockdown blocks GSK-3β inactivation and axon formation.\",\n      \"method\": \"Immunofluorescence localization, R-Ras siRNA knockdown, ILK siRNA knockdown, ILK membrane targeting construct, GSK-3β phosphorylation immunoblotting, axon formation assay in primary hippocampal neurons\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA knockdown at multiple pathway steps (R-Ras, ILK), membrane-targeted ILK rescue, clear epistatic pathway placement in primary neurons\",\n      \"pmids\": [\"17107957\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Cyclic AMP activates R-Ras through Epac (exchange protein directly activated by cAMP) via G protein-coupled receptors; Epac1 directly interacts with R-Ras and catalyzes GDP/GTP exchange in vitro; activated R-Ras specifically mediates GPCR-stimulated phospholipase D activation.\",\n      \"method\": \"Epac-specific cAMP analog, Epac1 siRNA knockdown, dominant-negative Rap GTPases, in vitro GEF assay (Epac1 + R-Ras), phospholipase D activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro GEF exchange assay plus multiple genetic/pharmacological validations in cells; two independent methods\",\n      \"pmids\": [\"16754664\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"R-Ras GAP is transcriptionally downregulated by NGF during PC12 neurite formation, allowing R-Ras activation to promote neurite growth; R-Ras GAP homozygous mutant mice die at E12.5–13.5 from hemorrhage due to underdeveloped adherens junctions in capillary endothelial cells.\",\n      \"method\": \"Stable R-Ras GAP overexpression in PC12 cells, NGF stimulation, neurite formation assay, R-Ras GAP knockin/knockout mouse generation, embryonic histology\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-based stable overexpression with functional readout plus genetic mouse model with vascular phenotype\",\n      \"pmids\": [\"17179160\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"R-Ras is enriched on early and recycling endosomes; endosomal R-Ras activity is higher than at the plasma membrane and correlates with accumulation of the Rgl2/Rlf GEF for RalA, leading to high endosomal RalA activity; R-Ras or RalA shRNA suppresses calcium-triggered exocytosis in PC12 cells.\",\n      \"method\": \"FRET-based R-Ras activity probe (subcellular), anti-R-Ras antibody localization, shRNA knockdown of R-Ras and RalA, calcium-triggered exocytosis assay in PC12 cells\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live-cell FRET activity imaging plus shRNA functional assay, single lab\",\n      \"pmids\": [\"17344481\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Mammalian Notch-1 intracellular domain (released by γ-secretase cleavage) activates R-Ras and thereby activates β1 integrins, independently of CSL-mediated transcription; Notch-1 reverses H-Ras/Raf-mediated integrin suppression without affecting ERK; Delta-like ligand-4 stimulates R-Ras-dependent α5β1 integrin adhesion.\",\n      \"method\": \"γ-secretase inhibitor, Notch mutants (inefficient cleavage, ankyrin repeat deletion, PEST domain truncation), R-Ras GTP-loading assay, integrin activation assay, Delta-like ligand-4 stimulation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple Notch mutants plus pharmacological inhibitor plus physiological ligand stimulation; single lab\",\n      \"pmids\": [\"17664272\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Transcription factor 8 (TCF8) activates R-Ras by binding CalDAG-GEFIII (an R-Ras GEF) in the cytosol, not through transcriptional regulation; TCF8-activated R-Ras suppresses endothelial tube formation.\",\n      \"method\": \"Co-immunoprecipitation of TCF8 and CalDAG-GEFIII, R-Ras GTP-loading assay, siRNA knockdown, tube formation assay in HUVECs\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single co-IP plus limited functional data, single lab, small study\",\n      \"pmids\": [\"19116136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Plexin-D1 exhibits R-Ras GAP activity requiring Rnd2 (not Rnd1); Sema3E/Plexin-D1 inhibits axon outgrowth of cortical neurons requiring Rnd2 and R-Ras downregulation; Plexin-C1 exhibits R-Ras GAP activity independently of any Rnd protein.\",\n      \"method\": \"R-Ras GTPase activity assay, co-immunoprecipitation of Rnd2 with Plexin-D1, Rnd2 siRNA, cell migration inhibition assay, cortical neuron axon outgrowth assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro GAP assay plus co-IP plus siRNA functional assays; defines Rnd requirement specificity across plexin subfamily\",\n      \"pmids\": [\"19136556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Fam38A (Piezo1 precursor) localizes at the ER and recruits R-Ras to the ER, where R-Ras activates calpain by increasing Ca2+ release from ER stores; calpain then cleaves talin to activate β1 integrins; siRNA knockdown of Fam38A, R-Ras, calpain, or talin each block integrin activation.\",\n      \"method\": \"siRNA knockdown of Fam38A/R-Ras/calpain/talin, Ca2+ release measurement, calpain activity assay, β1 integrin activation assay, subcellular co-localization (confocal)\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA knockdown at four pathway steps plus Ca2+ and calpain assays; defines an ER-based R-Ras signaling mechanism with multiple orthogonal validations\",\n      \"pmids\": [\"20016066\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Sema3E activates Plexin-D1 to inactivate R-Ras and stimulate Arf6, causing disassembly of integrin adhesive structures and inhibition of endothelial cell adhesion; R-Ras inactivation controls integrin activation status while Arf6 stimulation controls integrin intracellular trafficking.\",\n      \"method\": \"R-Ras GTP-loading assay, Arf6 activation assay, integrin adhesion and fibrillar adhesion assays, dominant-negative R-Ras/Arf6 constructs, endothelial cell retraction assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — parallel measurement of R-Ras and Arf6 activities with functional integrin assays, single lab\",\n      \"pmids\": [\"20385769\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Sema4D/Plexin-B1 R-Ras GAP activity promotes dephosphorylation and activation of PTEN (at Ser-380) through inhibition of casein kinase 2α; PTEN activation contributes to growth cone collapse downstream of R-Ras inactivation.\",\n      \"method\": \"PTEN phosphorylation immunoblotting, PTEN phosphatase activity assay, phospho-mimic/phospho-resistant PTEN mutants, casein kinase 2α activity assay, growth cone collapse assay in hippocampal neurons\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct PTEN phosphatase activity assay plus phospho-mutant epistasis plus CK2 inhibition; clear pathway from R-Ras GAP to PTEN activation\",\n      \"pmids\": [\"20610402\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"R-Ras colocalizes with and is endocytosed from membrane ruffles, trafficking via Rab11-positive vesicles; active R-Ras promotes ruffle formation and β1 integrin endocytosis; dominant-negative R-Ras and R-Ras siRNA prevent β1 integrin accumulation in ruffles and impair β1-integrin-mediated adhesion.\",\n      \"method\": \"GFP-R-Ras live-cell imaging, Rab11 co-localization, siRNA knockdown, β1 integrin endocytosis assay, TIRF microscopy\",\n      \"journal\": \"BMC cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live-cell imaging plus siRNA functional assays; single lab\",\n      \"pmids\": [\"20167113\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"DHHC19 is a palmitoyl transferase that specifically palmitoylates R-Ras (not H-Ras, N-Ras, K-Ras4A, RhoB, or Rap2); DHHC19 co-expression increases R-Ras palmitoylation approximately 2-fold, enhances R-Ras membrane and raft/caveolae association, and increases cell viability.\",\n      \"method\": \"Palmitoylation assay (metabolic labeling), membrane fractionation, raft/caveolae isolation, co-transfection in COS7 cells, cell viability assay\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct palmitoylation assay with substrate specificity testing across multiple GTPases; single lab\",\n      \"pmids\": [\"20074548\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"R-Ras interacts with filamin A (FLNa) via FLNa repeat 3; active R-Ras colocalizes with FLNa and coordinately increases cell migration and fibronectin matrix assembly; siRNA knockdown of endogenous R-Ras impairs FLNa-dependent fibronectin matrix assembly.\",\n      \"method\": \"Yeast two-hybrid screen, co-immunoprecipitation, GST-FLNa pulldown, FLNaΔ3 deletion mutant, co-localization immunofluorescence, siRNA knockdown, cell migration and fibronectin assembly assays\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus co-IP plus siRNA functional assay; multiple binding methods but single lab\",\n      \"pmids\": [\"20585650\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"R-Ras interacts with FLNa (repeat 3) in endothelial cells; co-knockdown of R-Ras and FLNa promotes vascular permeability, disorganizes VE-cadherin at adherens junctions, and increases Src (Y416) and VE-cadherin (Y731) phosphorylation; dominant-negative R-Ras-induced permeability is blocked by Src inhibitor PP2.\",\n      \"method\": \"Co-immunoprecipitation, FLNaΔ3 rescue experiments, siRNA knockdown, transendothelial electrical resistance, FITC-dextran permeability assay, VE-cadherin immunostaining\",\n      \"journal\": \"Journal of cellular physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus siRNA knockdown plus FLNaΔ3 rescue defining the R-Ras/FLNa complex in barrier function; single lab\",\n      \"pmids\": [\"21660952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"R-Ras-GTP binds RIN2 (Ras and Rab5 interacting protein) and converts it from a Rab5 GEF to an adaptor that binds Rab5-GTP; this promotes selective endocytosis of ligand-bound/active β1 integrins; the R-Ras/RIN2/Rab5 module then activates Rac1 via TIAM1 on early endosomes to drive endothelial cell adhesion.\",\n      \"method\": \"Co-immunoprecipitation of R-Ras with RIN2, active integrin endocytosis assay, Rac1 activation assay, TIAM1 localization, RIN2 siRNA, Rab5 GEF activity assay, dominant-negative constructs\",\n      \"journal\": \"Cell research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods defining the R-Ras→RIN2→Rab5→TIAM1→Rac1 pathway; endocytosis assay plus GTPase assays plus siRNA; single lab but comprehensive\",\n      \"pmids\": [\"22825554\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Palmitoylation of R-Ras is required for exit from the Golgi in post-Golgi vesicle membranes and trafficking to the plasma membrane; geranylgeranylation is required for membrane anchorage; palmitoylation-deficient R-Ras blocks membrane ruffling, PI3K interaction, PtdIns(3,4,5)P3 enrichment at plasma membrane, and R-Ras-dependent cell spreading.\",\n      \"method\": \"Palmitoylation-deficient mutant analysis, GFP-tagged R-Ras vesicle trafficking by live-cell imaging, Rab11 co-localization, PI3K co-immunoprecipitation, PtdIns(3,4,5)P3 reporter, cell spreading assay\",\n      \"journal\": \"Small GTPases\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — palmitoylation mutant functional analysis plus live-cell imaging plus PI3K interaction assay; single lab\",\n      \"pmids\": [\"22751447\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"R-Ras controls axon branching in cortical neurons through afadin: active R-Ras induces translocation of afadin to membranes via afadin's RA (Ras-association) domains; afadin RA domain and F-actin binding domain are required for axon branching; R-Ras and afadin interact endogenously during axon development.\",\n      \"method\": \"Co-immunoprecipitation of endogenous R-Ras and afadin, afadin domain deletion mutants, siRNA knockdown of afadin, R-Ras constitutively active expression, subcellular localization analysis in cortical neurons\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — endogenous co-IP plus domain mutant analysis plus siRNA in primary neurons; single lab\",\n      \"pmids\": [\"22593211\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"ORP3-hyperphosphorylated form (ORP3-P) selectively interacts with the ER membrane protein VAPA via FFAT-like and canonical FFAT motifs; ORP3-VAPA complexes are targeted to PM sites via the ORP3 PH domain; ORP3-VAPA co-expression induces R-Ras activation and downstream AktS473 phosphorylation and β1 integrin activity.\",\n      \"method\": \"ORP3 mutagenesis (FFAT motif), co-immunoprecipitation of ORP3-P with VAPA, β1 integrin activity assay, Akt phosphorylation, VAPA co-expression\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — mutant interaction mapping plus R-Ras activation readout; mechanism linking ORP3-VAPA to R-Ras is not fully reconstituted\",\n      \"pmids\": [\"25447204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"SHANK1 and SHANK3 limit integrin activation by sequestering GTP-bound R-Ras (and Rap1) via the SHANK SPN domain (revealed as a Ras-association domain by crystal structure); autism-related SHANK3 SPN mutations (R12C and L68P) disrupt G-protein interaction and fail to inhibit integrin activation along the Rap1-RIAM-talin axis.\",\n      \"method\": \"Crystal structure of SHANK3 N-terminal region, affinity measurements of SPN-R-Ras interaction, SHANK3 silencing (increased Rap1 activity, cell spreading/migration/invasion), SPN point mutant functional rescue assays in cancer cells and neurons\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus quantitative binding measurements plus functional mutagenesis and siRNA in multiple cell types; multiple orthogonal methods\",\n      \"pmids\": [\"28263956\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"R-Ras suppresses internalization/endocytosis of VEGFR2 in endothelial cells, thereby strongly inhibiting VEGF-induced autophosphorylation at all five major tyrosine sites; this suppression is partially dependent on VE-cadherin; silencing R-Ras increases VEGFR2 phosphorylation and R-Ras knockout mice show elevated VEGFR2 phosphorylation in tumor vasculature.\",\n      \"method\": \"VEGFR2 internalization assay, VEGFR2 phosphorylation immunoblotting (5 sites), R-Ras siRNA, R-Ras knockout mouse tumor model, VE-cadherin knockdown epistasis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — receptor internalization mechanism plus site-specific phosphorylation analysis plus in vivo validation in knockout mice; multiple orthogonal methods\",\n      \"pmids\": [\"25645912\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"R-Ras strongly suppresses VEGF-dependent activation of p38MAPK and downstream HSP27 phosphorylation in endothelial cells; silencing R-Ras by siRNA increases VEGF-induced membrane protrusion and migration, effects reversed by p38MAPK inhibitor SB203580, establishing R-Ras as a regulator of the p38MAPK-HSP27 axis.\",\n      \"method\": \"p38MAPK and HSP27 phosphorylation immunoblotting, R-Ras siRNA, p38MAPK inhibitor SB203580, cell migration assay, membrane protrusion assay\",\n      \"journal\": \"Journal of vascular research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA plus pharmacological inhibitor rescue in two orthogonal functional assays; single lab\",\n      \"pmids\": [\"27029009\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RASA1 (p120RasGAP) exerts its tumor-suppressive function specifically through its GAP activity toward R-Ras; RASA1 mutants (Y472H, L481F) found in melanoma lack GAP activity toward R-Ras; wild-type RASA1 suppresses soft agar colony formation via R-Ras; R-Ras promotes RalA activation among downstream effectors.\",\n      \"method\": \"Soft-agar colony formation assay, RASA1 GAP activity assay toward R-Ras, RASA1 point mutant expression, RalA activation assay\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct GAP activity measurement plus functional colony assay with mutants; single lab\",\n      \"pmids\": [\"26993606\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"R-Ras-Akt signaling stabilizes the microtubule cytoskeleton in endothelial cells, promoting endothelial lumenogenesis; VEGF-A-activated Akt does not similarly stabilize microtubules or drive lumen formation; R-Ras-Akt pathway is required in vivo for lumenization of new capillaries in ischemic muscle.\",\n      \"method\": \"R-Ras constitutively active and dominant-negative expression, microtubule stability assay, 3D lumen formation assay, R-Ras knockout mouse ischemia model, Akt inhibitor\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vitro mechanism (microtubule stabilization) validated in vivo with knockout mouse ischemia model; two orthogonal functional readouts\",\n      \"pmids\": [\"29170374\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Prolonged cAMP elevation transcriptionally represses RRAS gene expression in endothelial cells via a CREB3-dependent mechanism, disrupting VE-cadherin at adherens junctions and increasing vascular permeability; cAMP-induced plasma leakage from microvessels in mouse skin is mediated by RRAS repression.\",\n      \"method\": \"RT-PCR and immunoblotting of R-Ras upon cAMP elevation, CREB3 siRNA, R-Ras rescue transduction, VE-cadherin localization, TEER and FITC-dextran permeability assay, in vivo Miles assay in mice\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — transcriptional mechanism defined via CREB3 siRNA, rescued by R-Ras re-expression; validated in vivo with mouse permeability model\",\n      \"pmids\": [\"29775418\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"RasGRP2 (CalDAG-GEF) activates R-Ras (in addition to Rap1) in endothelial cells; the R-Ras-PI3K-Akt signaling pathway activated by RasGRP2 suppresses Bax-activation-induced apoptosis by promoting translocation of hexokinase-2 from cytoplasm to mitochondria.\",\n      \"method\": \"Rap1 and R-Ras GTP pull-down assays, Rap1 siRNA knockdown, R-Ras siRNA knockdown, Akt phosphorylation, Bax translocation assay, HK-2 localization, apoptosis assay\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — GTPase activation assay plus siRNA epistasis plus HK-2 translocation assay; single lab\",\n      \"pmids\": [\"31723205\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PI3KC2α synthesizes PI(3,4)P2 at focal adhesions, which recruits RASA3 (RasGAP); RASA3 at focal adhesions inactivates R-RAS, increasing focal adhesion turnover, cell migration, and invasion; inhibiting PI3KC2α or lowering RASA3 activity reduces metastasis in PI3KC2α-overexpressing breast cancer models.\",\n      \"method\": \"PI3KC2α knockdown/overexpression, PI(3,4)P2 localization at focal adhesions, RASA3 co-localization and recruitment assay, R-RAS GTP-loading assay, focal adhesion turnover assay, in vivo metastasis model\",\n      \"journal\": \"Advanced science (Weinheim, Baden-Wurttemberg, Germany)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal assays establishing PI3KC2α→PI(3,4)P2→RASA3→R-Ras inactivation axis; single lab but comprehensive in vitro and in vivo data\",\n      \"pmids\": [\"35098698\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"FOXF1 directly activates the RRAS gene promoter through transcriptional activation in endothelial cells; endothelial-specific Foxf1 inhibition impairs R-Ras signaling and increases collagen deposition; nanoparticle delivery of Foxf1 cDNA decreases pulmonary fibrosis, with the mechanism involving FOXF1-dependent R-Ras transcription.\",\n      \"method\": \"Single-cell RNA-sequencing, FOXF1 promoter luciferase/ChIP (implied by 'direct transcriptional activation'), endothelial-specific Foxf1 knockout mouse, R-Ras signaling analysis, nanoparticle Foxf1 delivery in bleomycin mouse model\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic mouse model plus in vivo rescue experiment; RRAS as a direct FOXF1 target supported by promoter analysis, single lab\",\n      \"pmids\": [\"37137915\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"R-Ras is a Ras-family small GTPase that cycles between GDP-bound (inactive) and GTP-bound (active) states regulated by multiple GEFs (RasGRF, C3G, CalDAG-GEFs, Epac1) and GAPs (p120RasGAP, NF1, R-Ras GAP, and plexin receptors acting directly as GAPs); its best-characterized function is the positive regulation of integrin ligand-binding affinity (inside-out signaling) through a PI3K-dependent pathway, with additional distinct effectors including RLIP76, afadin, RIN2, PLCε, and ILK; its activity and localization are modulated by palmitoylation (by DHHC19) and by tyrosine phosphorylation at Y66 by EphB2 and Src (suppressing integrin activation); plexin-B1 and -D1 receptors serve as direct R-Ras GAPs requiring Rnd1/Rnd2 to mediate semaphorin-induced growth cone collapse and repulsive axon guidance via sequential inactivation of PI3K, dephosphorylation of Akt, activation of GSK-3β and PTEN; in the vasculature R-Ras stabilizes endothelial barriers by maintaining VE-cadherin junctions and suppressing VEGFR2 internalization/autophosphorylation, and promotes endothelial lumenogenesis via Akt-dependent microtubule stabilization.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"R-Ras (RRAS) is a membrane-anchored Ras-family small GTPase whose principal cellular role is the positive control of integrin ligand-binding affinity and the resulting programs of cell adhesion, spreading, and migration (\\\"inside-out\\\" signaling) [#10]. It cycles between GDP- and GTP-bound states under the control of a broad set of GEFs — including RasGRF, C3G, the CalDAG-GEF/RasGRP family, Epac1, and AND-34/BCAR3 — and GAPs including p120RasGAP, NF-1, and a dedicated ~98-kDa R-Ras GAP [#8, #18, #42]. Unlike classical Ras, active R-Ras does not drive the Raf–MEK–ERK axis but instead signals through PI 3-kinase to activate Akt, and this PI3K branch is essential for both its transforming activity and its pro-adhesive, pro-survival functions [#12, #17]. Membrane targeting and effector engagement depend on C-terminal palmitoylation (C213) and geranylgeranylation, which direct Golgi exit, focal-adhesion localization, and productive PI3K coupling [#28, #56]. Beyond PI3K, GTP-bound R-Ras engages distinct effectors to remodel the cytoskeleton and traffic integrins: RLIP76/RalBP1 and an Arf6 cascade, the proline-rich/Nck adaptor link, PLCε-driven membrane protrusion, and a RIN2→Rab5→TIAM1→Rac1 module that drives endocytosis of active β1 integrins [#23, #37, #39, #55]. R-Ras activity is suppressed by tyrosine phosphorylation at Y66 by EphB2 and Src, and by plexin receptors that act as direct R-Ras GAPs: plexin-B1 (with Rnd1), plexin-D1 (with Rnd2), and plexin-C1 (Rnd-independent) inactivate R-Ras in response to semaphorins to mediate growth cone collapse and repulsive guidance through sequential loss of PI3K signaling, Akt dephosphorylation, GSK-3β and PTEN activation [#13, #25, #30, #47, #35, #50]. In the vasculature R-Ras stabilizes endothelial barriers by maintaining VE-cadherin junctions, suppressing VEGFR2 internalization and autophosphorylation, and dampening p38MAPK–HSP27 signaling, and it promotes endothelial lumenogenesis via Akt-dependent microtubule stabilization [#60, #61, #63]; its endothelial expression is set transcriptionally by FOXF1 and repressed by cAMP/CREB3 [#64, #67].\",\n  \"teleology\": [\n    {\n      \"year\": 1987,\n      \"claim\": \"Established R-Ras as a bona fide membrane-associated, lipid-modified GTP-binding protein analogous to H-Ras, defining its biochemical identity.\",\n      \"evidence\": \"Metabolic [3H]palmitate labeling, membrane fractionation, and GTP-binding/autokinase assays on expressed protein\",\n      \"pmids\": [\"3313005\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No cellular function assigned\", \"Effectors and regulators unidentified\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"Showed R-Ras GTPase activity is controlled by the canonical 125-kDa rasGAP via its effector domain, placing R-Ras within Ras-family regulatory logic while hinting at lipid-modulated regulation.\",\n      \"evidence\": \"In vitro GTPase-activating assays with mammalian extracts and defined phospholipids\",\n      \"pmids\": [\"2491843\", \"2513485\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological GAP not yet identified\", \"Functional consequence of GAP regulation unknown\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"Linked R-Ras to apoptosis regulation by identifying a physical Bcl-2 interaction through its C-terminus, the first effector-type partner.\",\n      \"evidence\": \"Yeast two-hybrid and co-immunoprecipitation from human cell extracts\",\n      \"pmids\": [\"8232588\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional direction of Bcl-2 interaction not resolved here\", \"GTP-dependence not established\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Defined R-Ras as a transforming GTPase that engages Raf-1 and RalGDS in a GTP-dependent manner and cooperates with c-raf-1, raising the question of which effectors are physiological.\",\n      \"evidence\": \"Yeast two-hybrid, in vitro binding with purified proteins, site-directed mutagenesis and NIH3T3 transformation assays\",\n      \"pmids\": [\"8002932\", \"7809086\", \"8108110\", \"8084601\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Raf/RalGDS binding is physiologically relevant unresolved\", \"No distinct R-Ras-specific effector identified\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Resolved the apoptosis question by placing Bcl-2 downstream of R-Ras and identified a dedicated R-Ras-specific GAP, distinguishing R-Ras regulation from classical Ras.\",\n      \"evidence\": \"IL-3-withdrawal apoptosis assays with Bcl-2 epistasis; GST-R-Ras affinity purification and reconstituted GAP assays\",\n      \"pmids\": [\"7744959\", \"8530488\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity/cloning of the R-Ras-specific GAP only partially defined\", \"Apoptosis pathway intermediates between R-Ras and Bcl-2 unclear\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Identified the defining cellular function of R-Ras — control of integrin ligand-binding affinity (inside-out signaling) — and showed its weak/nonspecific binding to Raf/RalGDS argues against those as primary effectors.\",\n      \"evidence\": \"Activated/dominant-negative R-Ras with integrin affinity and adhesion assays; quantitative solution binding measurements\",\n      \"pmids\": [\"8620538\", \"8636102\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effector for integrin control not yet identified\", \"Mechanism connecting R-Ras to integrin cytoplasmic tail unknown\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Established PI 3-kinase/Akt as the central R-Ras effector branch, distinguishing it from the Ras-Raf-MAPK axis.\",\n      \"evidence\": \"Co-transfection PI3K lipid product and PKB/Akt kinase assays with wortmannin\",\n      \"pmids\": [\"8999998\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs indirect PI3K activation not fully resolved\", \"Link from PI3K to integrin affinity not yet mapped\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Showed R-Ras activity is suppressed by EphB2-mediated phosphorylation at Y66 and recruited to EphB2 via SHEP1, defining an anti-adhesive regulatory input, while effector-loop mutagenesis dissociated transformation from adhesion/survival and pinned both PI3K-dependent functions.\",\n      \"evidence\": \"Y66F mutagenesis with EphB2 activation and adhesion rescue; yeast two-hybrid/co-IP for SHEP1; systematic effector-loop mutants with PI3K/Akt inhibitors\",\n      \"pmids\": [\"10570155\", \"10542222\", \"10454580\", \"10352023\", \"10359597\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"SHEP1 GEF exchange activity on R-Ras not directly demonstrated\", \"How PI3K vs PKC branches diverge for invasion incompletely defined\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Mapped the regulator landscape of R-Ras (multiple GEFs and GAPs) and identified non-PI3K outputs — a GTP-independent Nck/proline-rich link, cAMP/Epac activation, and JNK/MLK3 and PLD activation — broadening its effector repertoire.\",\n      \"evidence\": \"In vitro and cell-based GEF/GAP assays; GST-SH3 pulldowns and adhesion mutants; Epac in vitro GEF assay; JNK kinase assays with MLK3 dominant-negatives\",\n      \"pmids\": [\"10777492\", \"10835426\", \"10896938\", \"10671570\", \"16754664\", \"10777559\", \"11134082\", \"10801791\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which GEF/GAP pairs operate in which cell context unresolved\", \"Some PI3K-dependence findings conflict across cell types\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Confirmed R-Ras suppression by Src at Y66 and extended its function to Rap1-dependent phagocytic integrin activation, reinforcing adhesion control over mitogenic output.\",\n      \"evidence\": \"In vitro and cellular Src kinase assays, Y66F rescue, co-IP; microinjection and macrophage phagocytosis assays\",\n      \"pmids\": [\"11682467\", \"11257001\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Interplay between Src and EphB2 phosphorylation at Y66 not resolved here\", \"Role of Rap1 vs R-Ras in phagocytosis not separated\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Defined the membrane-targeting determinants (C-terminal HVR, palmitoylation at C213) required for focal-adhesion localization and showed active R-Ras enhances FAK/p130Cas adhesion signaling; introduced ORP3 as an interacting adhesion regulator.\",\n      \"evidence\": \"H-Ras/R-Ras chimeras, C213A mutagenesis, fractionation, immunofluorescence; phospho-FAK/p130Cas immunoblotting; co-IP and siRNA of ORP3\",\n      \"pmids\": [\"12890755\", \"12529399\", \"18270267\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which ORP3 modulates R-Ras unresolved\", \"How palmitoylation gates effector access not yet defined\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Established plexin receptors as direct R-Ras GAPs requiring Rnd1, revealing the mechanism (intramolecular C1–C2 release, ligand-induced clustering) and a neuronal function in semaphorin-induced growth cone collapse; in parallel, defined R-Ras leading-edge control of Rac/Rho balance via PI3K.\",\n      \"evidence\": \"Reconstituted R-Ras GAP assays, domain dissection, antibody-induced clustering, growth cone collapse in hippocampal neurons; Rho/Rac pull-downs with activity imaging and effector mutants\",\n      \"pmids\": [\"15297673\", \"15601954\", \"15525681\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct R-Ras effectors mediating Rac/Rho balance not all identified\", \"Whether plexin GAP activity operates outside neurons not addressed\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identified the unique N-terminal extension as required for Rac activation and showed R-Ras as a required downstream mediator of EphB2 in glioma, connecting receptor signaling to invasive behavior.\",\n      \"evidence\": \"N-terminal truncation mutants with Rac pull-downs; R-Ras siRNA with glioma adhesion/invasion assays and EphB2 co-IP\",\n      \"pmids\": [\"15772154\", \"16049340\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Effector coupling N-terminus to Rac unidentified\", \"How R-Ras both promotes and is inhibited downstream of Eph reconciled\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Established a coherent semaphorin/plexin→R-Ras-off pathway (PI3K loss→Akt dephosphorylation→GSK-3β→CRMP-2; β1 integrin suppression), defined dual Eph inactivation (Y66 + p120RasGAP), and identified R-Ras-specific effectors RLIP76 and PLCε plus endosomal RalA signaling and axon-specification via ILK.\",\n      \"evidence\": \"Plexin-B1 GAP assays with Akt/GSK-3β/PTEN readouts; Eph mutant dissection; direct GTP-dependent RLIP76 binding with Arf6 epistasis; PLCε co-IP/siRNA; FRET endosomal activity imaging; ILK siRNA and rescue in primary neurons\",\n      \"pmids\": [\"16799460\", \"16702230\", \"16522685\", \"16966426\", \"16537651\", \"17107957\", \"17344481\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How a single GTPase coordinates opposing migratory outputs across cell types unresolved\", \"Quantitative effector partitioning (RLIP76 vs PLCε vs PI3K) undefined\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Showed RalGDS-family effector RalA acts downstream on endosomes for exocytosis, and that Notch-1 intracellular domain activates R-Ras to drive β1 integrin adhesion independently of CSL transcription, expanding upstream activators.\",\n      \"evidence\": \"FRET activity probes and shRNA exocytosis assays; γ-secretase inhibitors, Notch mutants and R-Ras GTP-loading with integrin assays\",\n      \"pmids\": [\"17344481\", \"17664272\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GEF coupling Notch to R-Ras not identified\", \"Direct vs indirect Notch–R-Ras link unresolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Defined an ER-based activation mechanism (Fam38A/Piezo1→R-Ras→Ca2+/calpain→talin cleavage→β1 integrin), the DHHC19 palmitoyltransferase as R-Ras-specific, plexin-D1/Rnd2 GAP activity, and endosomal trafficking of active integrins via Rab11.\",\n      \"evidence\": \"Four-step siRNA epistasis with Ca2+/calpain assays; substrate-specific palmitoylation assays; plexin-D1/Rnd2 GAP and co-IP; live-cell imaging and integrin endocytosis assays\",\n      \"pmids\": [\"20016066\", \"20074548\", \"20385769\", \"20167113\", \"20610402\", \"19136556\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ER-localized R-Ras integrates with plasma-membrane pool unclear\", \"Plexin subfamily Rnd-requirement logic only partially explained\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Defined the R-Ras→RIN2→Rab5→TIAM1→Rac1 module coupling active-integrin endocytosis to endothelial adhesion, and identified afadin as the effector for R-Ras-controlled axon branching, mechanistically integrating trafficking and cytoskeletal outputs.\",\n      \"evidence\": \"Co-IP, integrin endocytosis and Rab5 GEF assays, Rac1 activation, siRNA; endogenous R-Ras/afadin co-IP and domain mutants in cortical neurons\",\n      \"pmids\": [\"22825554\", \"22593211\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How R-Ras switches RIN2 from GEF to adaptor structurally undefined\", \"Generality of afadin pathway beyond cortical neurons untested\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Identified the R-Ras/filamin A complex as a regulator of fibronectin matrix assembly and endothelial barrier integrity, mechanistically linking R-Ras to VE-cadherin junction stability and Src restraint.\",\n      \"evidence\": \"Yeast two-hybrid/co-IP/GST pulldowns with FLNa repeat-3 mutants; siRNA with permeability (TEER, FITC-dextran) and VE-cadherin/Src phospho-analysis\",\n      \"pmids\": [\"20585650\", \"21660952\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether FLNa binding is GTP-dependent not established\", \"Mechanism by which R-Ras restrains Src at junctions unclear\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined R-Ras as a suppressor of VEGFR2 endocytosis and autophosphorylation in endothelium, providing a junction-stabilizing, anti-permeability mechanism validated in knockout mice.\",\n      \"evidence\": \"VEGFR2 internalization and five-site phospho-analysis, R-Ras siRNA, VE-cadherin epistasis, R-Ras knockout tumor vasculature\",\n      \"pmids\": [\"25645912\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct effector mediating VEGFR2 trafficking suppression unidentified\", \"Relationship to RIN2/Rab5 endocytic module unresolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Extended endothelial R-Ras control to the VEGF→p38MAPK–HSP27 axis, showing R-Ras dampens migration-promoting signaling, and showed RASA1/p120RasGAP tumor suppression operates specifically through R-Ras GAP activity.\",\n      \"evidence\": \"p38/HSP27 phospho-immunoblotting with SB203580 rescue; RASA1 GAP assays and melanoma-mutant colony formation with RalA readout\",\n      \"pmids\": [\"27029009\", \"26993606\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic link from R-Ras to p38 not defined\", \"How RASA1 mutations select for R-Ras hyperactivity in tumors unclear\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showed R-Ras–Akt signaling stabilizes microtubules to drive endothelial lumenogenesis, a function distinct from VEGF-Akt, validated in vivo, sharpening the role of the PI3K–Akt branch in vascular morphogenesis.\",\n      \"evidence\": \"Constitutively active/dominant-negative R-Ras, microtubule stability and 3D lumen assays, Akt inhibition, knockout-mouse ischemia model\",\n      \"pmids\": [\"29170374\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Microtubule-binding effector downstream of Akt unidentified\", \"Why VEGF-Akt fails to phenocopy R-Ras-Akt undefined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Provided structural definition of GTP-bound R-Ras sequestration by SHANK SPN domains, with autism-related mutations disrupting the interaction, linking R-Ras to integrin restraint and neurological disease.\",\n      \"evidence\": \"Crystal structure of SHANK3 N-terminus, affinity measurements, SHANK silencing and SPN point-mutant functional assays; ORP3-P/VAPA interaction mapping with R-Ras activation\",\n      \"pmids\": [\"28263956\", \"25447204\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether SHANK sequestration operates physiologically in neurons in vivo not established\", \"ORP3-VAPA to R-Ras activation mechanism not reconstituted\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Connected the CalDAG-GEF RasGRP2 to endothelial R-Ras–PI3K–Akt anti-apoptotic signaling acting through hexokinase-2 mitochondrial translocation, extending R-Ras survival functions into the vasculature.\",\n      \"evidence\": \"Rap1/R-Ras pull-downs, siRNA epistasis, Akt/Bax/HK-2 localization and apoptosis assays\",\n      \"pmids\": [\"31723205\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contributions of Rap1 vs R-Ras not fully separated\", \"Mechanism linking Akt to HK-2 translocation undefined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined a focal-adhesion lipid–GAP circuit (PI3KC2α→PI(3,4)P2→RASA3→R-Ras-off) controlling adhesion turnover and metastasis, providing a spatially localized inactivation mechanism.\",\n      \"evidence\": \"PI3KC2α knockdown/overexpression, PI(3,4)P2 and RASA3 localization, R-Ras GTP-loading, focal-adhesion turnover and in vivo metastasis assays\",\n      \"pmids\": [\"35098698\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Generality across cancer types untested\", \"How RASA3 selectivity for R-Ras is achieved unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Established FOXF1 as a direct transcriptional activator of RRAS in endothelium and showed cAMP/CREB3 represses RRAS, identifying transcriptional control as a determinant of endothelial R-Ras-dependent barrier function and fibrosis.\",\n      \"evidence\": \"scRNA-seq, promoter analysis, endothelial Foxf1 knockout and nanoparticle rescue; cAMP/CREB3 siRNA with permeability and Miles assays\",\n      \"pmids\": [\"37137915\", \"29775418\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct FOXF1 promoter occupancy details limited\", \"How transcriptional and post-translational regulation are integrated unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis by which R-Ras partitions among its many effectors (PI3K, RLIP76, PLCε, RIN2, afadin, RalGDS/RalA) in a given subcellular compartment, and how palmitoylation/phosphorylation and localized GAPs choreograph context-specific output, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model of R-Ras effector selection\", \"Quantitative effector partitioning across compartments undefined\", \"In vivo essentiality of individual effector branches untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003924\", \"supporting_discovery_ids\": [1, 8, 18, 30, 47]},\n      {\"term_id\": \"GO:0005525\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [10, 12]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [59]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 28, 56]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [28, 56]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [44, 51, 55]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [48, 58]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10, 12, 30, 35]},\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [10, 15, 53]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [30, 41, 47, 57, 63]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [9, 65]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [51, 55, 60]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"RASA1\", \"RAF1\", \"RALGDS\", \"RLIP76\", \"RIN2\", \"FLNA\", \"PLCE1\", \"MRAS-GAP\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win"}}