{"gene":"RASGRP3","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2000,"finding":"CalDAG-GEFIII (RasGRP3) is a guanine nucleotide exchange factor that promotes GDP-to-GTP exchange on Ha-Ras, R-Ras, and Rap1 both in intact cells and in vitro, exhibiting broader substrate specificity than related family members CalDAG-GEFI and CalDAG-GEFII. Expression of RasGRP3 activates ERK/MAPK, and co-activation of Rap1 by RasGRP3 attenuates Ras-MAPK-dependent neuronal differentiation and cellular transformation.","method":"In vitro GEF assay (GTP/GDP ratio measurement), transfection in 293T cells, PC12 neuronal differentiation assay, Rat1A anchorage-independent growth assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro GEF reconstitution with multiple GTPase substrates, complemented by cell-based functional assays","pmids":["10835426"],"is_preprint":false},{"year":2001,"finding":"RasGRP3 binds phorbol esters with high affinity via its C1 domain in an anionic phospholipid-dependent manner, and phorbol ester binding activates RasGRP3 exchange activity (increasing Ras-GTP and ERK phosphorylation) and causes redistribution of RasGRP3 to the plasma membrane and/or perinuclear area, identifying RasGRP3 as a PKC-independent phorbol ester receptor linking DAG/phorbol ester signaling to Ras activation.","method":"Phorbol ester binding assay, Ras-GTP pull-down, ERK phosphorylation (Western blot), GFP-RasGRP3 live-cell imaging/redistribution in HEK-293 cells","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct ligand-binding assay plus functional GEF activation and subcellular redistribution, replicated across multiple methods in one study and consistent with subsequent papers","pmids":["11221888"],"is_preprint":false},{"year":2003,"finding":"RasGRP3 is phosphorylated coincident with Ras activation after PMA stimulation of B cells; PKC inhibitors attenuate both Ras activation and RasGRP3 phosphorylation. PKC-theta and PKC-beta2 phosphorylate RasGRP3 in vitro, and a dominant-active PKC-theta mutant co-expressed with RasGRP3 in HEK-293 cells enhances Ras-ERK signaling. PMA also induces membrane association of RasGRP3, indicating dual regulation by DAG-mediated membrane recruitment and PKC-dependent phosphorylation.","method":"In vitro kinase assay with PKC-theta and PKC-beta2, co-immunoprecipitation, Ras-GTP pull-down, pharmacological PKC inhibition, subcellular fractionation","journal":"Blood","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro kinase assay plus cell-based pharmacological dissection, two independent orthogonal approaches, consistent with multiple subsequent studies","pmids":["12730099"],"is_preprint":false},{"year":2004,"finding":"PKC phosphorylates RasGRP3 specifically on threonine 133 (identified by mass spectrometry in vitro). A Thr133Ala substitution renders RasGRP3 a poor PKC substrate in vitro and a poor Ras activator in vivo. Anti-phospho-Thr133 antibodies detect phosphorylated RasGRP3 in B cells after BCR stimulation or DAG analog treatment; PKC inhibitors block both Thr133 phosphorylation and Ras-ERK signaling. This defines Thr133 phosphorylation as a mechanistic link between PKC and Ras activation downstream of BCR signaling.","method":"In vitro kinase assay with mass spectrometry (Thr133 identification), site-directed mutagenesis (Thr133Ala), anti-phosphopeptide antibody, pharmacological PKC inhibition, Ras-GTP pull-down in B cells","journal":"Blood","confidence":"High","confidence_rationale":"Tier 1 / Strong — MS-identified phosphosite, mutagenesis validation, antibody confirmation in cells; independently replicated by Aiba et al. 2004 (PMID 15545601)","pmids":["15657177","15545601"],"is_preprint":false},{"year":2004,"finding":"RasGRP3 Thr133 is phosphorylated upon BCR cross-linking; deletion of PLC-gamma2 or pharmacological inhibition of conventional PKCs markedly reduces both Thr133 phosphorylation and Ras activation. Thr133Ala mutation severely impairs RasGRP3-mediated Ras activation in BCR signaling, indicating that PKC (activated by DAG downstream of PLC-gamma2) phosphorylates RasGRP3 at Thr133 to achieve full activation.","method":"BCR cross-linking, pharmacological PKC inhibition, Thr133Ala mutagenesis, Ras activation assay in B cell lines","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — mutagenesis and genetic (PLC-gamma2 deletion) combined with pharmacological approach; independently corroborates PMID 15657177","pmids":["15545601"],"is_preprint":false},{"year":2004,"finding":"PKCdelta physically associates with RasGRP3 upon PMA stimulation, as shown by co-immunoprecipitation and co-localization in the perinuclear region. PKCdelta phosphorylates RasGRP3 in vitro (on serine residues). A PKCdelta kinase-dead mutant blocks the PMA-induced mobility shift of RasGRP3. Co-expression of PKCdelta and RasGRP3 modulates Erk1/2 activation compared with either alone.","method":"Co-immunoprecipitation, in vitro kinase assay, kinase-dead mutant expression, pharmacological inhibition (rottlerin), immunofluorescence colocalization","journal":"Molecular pharmacology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro kinase assay + co-IP + mutagenesis, single lab but multiple orthogonal methods","pmids":["15213298"],"is_preprint":false},{"year":2004,"finding":"EGF receptor activates Rap2B-dependent stimulation of PLC-epsilon through RasGRP3: EGF induces tyrosine phosphorylation of RasGRP3 (but not RasGRP1) by c-Src; inhibition of c-Src blocks EGF-induced Rap2B-GTP loading and PLC-epsilon stimulation. RasGRP3 overexpression enhances GTP loading of Rap2B and PLC/Ca2+ signaling by EGF receptor, establishing a pathway: EGF receptor → c-Src → RasGRP3 (Tyr phosphorylation) → Rap2B → PLC-epsilon.","method":"Co-immunoprecipitation (Rap2B-PLC-epsilon), dominant-negative Rap2B expression, c-Src pharmacological inhibition, RasGRP3 overexpression, Ca2+ signaling measurement, GTP-loading assay in HEK-293 cells","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus pharmacological epistasis and overexpression, single lab but multiple orthogonal methods","pmids":["15143162"],"is_preprint":false},{"year":2004,"finding":"RasGRP3 is expressed in embryonic blood vessels, downregulated in mature vessels, and re-expressed in angiogenic vessels during pregnancy and tumorigenesis. RasGRP3 is upregulated downstream of VEGF stimulation in HUVECs. In ES cell-derived vascular models, loss of RasGRP3 abolishes phorbol ester (PMA)-induced aberrant endothelial morphogenesis (formation of large sheets rather than branched vessels), establishing RasGRP3 as a required endothelial phorbol ester receptor mediating DAG-dependent angiogenic responses.","method":"Gene trap loss-of-function mouse model, ES cell vascular differentiation assay, PMA treatment, RT-PCR/in situ hybridization for expression pattern","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic loss-of-function with defined morphogenetic phenotype, single lab","pmids":["15572660"],"is_preprint":false},{"year":2005,"finding":"RasGRP1 and RasGRP3 both contribute to BCR-induced Ras-GTP generation in B cells, with RasGRP3 alone responsible for maintaining basal Ras-GTP levels in unstimulated B cells. Double-null mutant mice show no defect in B cell development, but loss of RasGRP3 leads to humoral deficiencies (hypogammaglobulinemia, isotype-specific Ab induction defects) and loss of BCR-induced B cell proliferation. RasGRP-independent pathways support LPS-induced proliferation.","method":"Single and double Rasgrp1/Rasgrp3 knock-out mice, Ras-GTP pull-down, B cell proliferation assay, in vivo immunization, serum Ig measurement","journal":"Journal of immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean genetic double KO with multiple functional readouts (Ras-GTP, proliferation, humoral immunity in vivo)","pmids":["16301621"],"is_preprint":false},{"year":2005,"finding":"Fluorescent phorbol esters and complementary GFP-RasGRP3 fusion constructs showed that RasGRP3 co-localizes with and translocates to intracellular membranes upon phorbol ester treatment, with translocation pattern following ligand localization. The rate of phorbol ester uptake influences the pattern of RasGRP3 translocation.","method":"Live-cell fluorescence imaging with fluorescently labeled phorbol esters and GFP/DsRed fusion constructs for RasGRP3 in CHO cells","journal":"Molecular cancer therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct live-cell imaging of localization dynamics with functional implication, single lab","pmids":["15657361"],"is_preprint":false},{"year":2005,"finding":"RasGRP3 is expressed in endocrine tissues and mediates phorbol ester-induced exocytosis in a PKC-independent manner; this effect was partially blocked by PKC inhibitors but not MEK inhibitor, despite MEK inhibitor blocking phorbol ester-induced ERK1/2 phosphorylation.","method":"Exocytosis assay in endocrine cells, pharmacological inhibition of PKC and MEK, ERK1/2 phosphorylation (Western blot)","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single functional assay without molecular identification of GEF-exocytosis mechanism","pmids":["15737652"],"is_preprint":false},{"year":2006,"finding":"Dynein light chain 1 (DLC1) is a novel RasGRP3-interacting protein identified by yeast two-hybrid screening of a human brain cDNA library and confirmed by in vitro pull-down and co-immunoprecipitation. The interaction requires the C-terminal 127 amino acids of RasGRP3. A truncated RasGRP3 lacking this C-terminal domain cannot interact with DLC1 and displays dramatically altered subcellular localization (strong reticular distribution with perinuclear and nuclear accumulation), suggesting DLC1 acts as an anchoring protein regulating RasGRP3 subcellular localization.","method":"Yeast two-hybrid screen, in vitro pull-down, co-immunoprecipitation, C-terminal truncation mutagenesis, subcellular localization by fluorescence microscopy","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid confirmed by in vitro and in vivo binding, mutagenesis defines interaction domain and functional consequence on localization; single lab","pmids":["17012239"],"is_preprint":false},{"year":2010,"finding":"In prostate cancer cell lines, RasGRP3 maintains Ras-GTP formation; siRNA knockdown reduces Ras-GTP, AKT phosphorylation, and ERK1/2 phosphorylation, inhibits proliferation, migration, and anchorage-independent growth, and induces apoptosis and sensitizes cells to carboplatin. Ectopic RasGRP3 expression in LNCaP cells elevates Ras-GTP and stimulates proliferation, defining RasGRP3 as an upstream activator of both AKT and ERK pathways in prostate cancer.","method":"siRNA knockdown, Ras-GTP pull-down, AKT/ERK phosphorylation (Western blot), proliferation assay, migration assay, soft-agar colony formation, xenograft mouse model","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss- and gain-of-function with multiple downstream pathway readouts, single lab","pmids":["20876802"],"is_preprint":false},{"year":2011,"finding":"RasGRP3 mediates diabetes-induced vascular developmental defects: embryos lacking Rasgrp3 function show dramatically attenuated diabetes-induced developmental defects. Endothelial cells expressing activated RasGRP3 have elevated Ras-ERK signaling and perturbed migration; cells lacking Rasgrp3 have attenuated Ras-ERK signaling and fail to migrate in response to endothelin-1. This establishes RasGRP3 in a pathway: endothelin-1 (upstream input) → RasGRP3 → Ras/MEK/ERK → endothelial migration.","method":"Rasgrp3 loss-of-function mouse embryos from diabetic mothers, activated RasGRP3 overexpression in primary endothelial cells, endothelin-1 stimulation, Ras-ERK signaling (Western blot), endothelial migration assay","journal":"Circulation research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function in vivo combined with gain/loss in primary cells with defined signaling readouts; single lab","pmids":["21474816"],"is_preprint":false},{"year":2014,"finding":"RasGRP3 activates Rap1 in macrophages downstream of TLR3/4/9 stimulation. In RasGRP3-deficient RAW264.7 cells (generated by CRISPR-Cas9), TLR-induced Rap1 activation is inhibited while ERK1/2 activation is enhanced. RasGRP3 thus limits IL-6 production in macrophages exposed to low levels of TLR agonists by activating Rap1, setting a threshold for inflammatory responses.","method":"CRISPR-Cas9 knockout of RasGRP3 in RAW264.7 cells, Rap1-GTP pull-down, ERK1/2 phosphorylation (Western blot), IL-6 cytokine measurement, in vivo colitis and arthritis models","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Strong — CRISPR KO with direct GTPase activation assay (Rap1-GTP), multiple TLR stimuli, and in vivo disease models in same study","pmids":["25118589"],"is_preprint":false},{"year":2015,"finding":"RasGRP3 interacts with Arp3 (actin-related protein 3) in glioma cells, identified by pull-down/mass spectrometry and validated by co-immunoprecipitation and immunofluorescence. PMA-induced translocation of RasGRP3 to the perinuclear region increases its association with Arp3. Silencing Arp3 partially abrogates RasGRP3-induced glioma cell migration and invasion, linking RasGRP3 to actin polymerization-dependent cell motility.","method":"Pull-down assay with mass spectrometry, co-immunoprecipitation, immunofluorescence, siRNA knockdown, cell migration/invasion assay","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — MS-identified interaction confirmed by co-IP and localization, functional epistasis by Arp3 knockdown; single lab","pmids":["25682201"],"is_preprint":false},{"year":2017,"finding":"In GNAQ/GNA11 mutant uveal melanoma, MAPK activation requires Ras and is caused by RasGRP3, which is selectively overexpressed in response to GNAQ/11 mutation. PKCδ and PKCε are required and sufficient for MAPK activation upstream of RasGRP3. RasGRP3 is activated by two mechanisms: PKCδ/ε-dependent phosphorylation and PKC-independent DAG-mediated membrane recruitment, explaining the limited durability of PKC inhibitor effects on MAPK suppression.","method":"siRNA/shRNA knockdown, pharmacological PKC inhibition, Ras-GTP pull-down, ERK phosphorylation (Western blot), reconstitution of signaling in cell lines, expression analysis in human UM samples","journal":"Cancer cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — mechanistic dissection with loss-of-function (siRNA) and pharmacological epistasis in multiple UM cell lines, two activation mechanisms defined; replicated independently (PMID 29490280)","pmids":["28486107"],"is_preprint":false},{"year":2018,"finding":"In a GNA11Q209L mouse model of uveal melanoma, RasGRP3 is specifically expressed in GNAQ/GNA11-driven melanomas (identified by integrative transcriptome analysis). In human UM cell lines and murine models, RasGRP3 is specifically required for GNAQ/GNA11-driven Ras activation and tumorigenesis, confirming RasGRP3 as an essential node in the Gαq/11 → Ras signaling axis.","method":"GNA11Q209L knock-in mouse model, transcriptome analysis (human and murine melanomas), siRNA/shRNA knockdown in human UM cell lines, Ras-GTP pull-down, xenograft tumorigenesis assay","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic mouse model plus human cell line loss-of-function with direct Ras-GTP measurement; independently corroborates PMID 28486107","pmids":["29490280"],"is_preprint":false},{"year":2018,"finding":"DAG-lactone compound 96 shows 73-fold selectivity for RasGRP3 versus PKCα and 45-fold versus PKCε in C1-domain binding assays in vitro, and in intact cells induces Ras activation (downstream of RasGRP) with 8–29-fold selectivity relative to PKCδ phosphorylation, establishing that selective RasGRP3 C1-domain targeting is achievable with this ligand scaffold.","method":"In vitro C1-domain competitive binding assay, cell-based Ras-GTP and PKCδ phosphorylation assay","journal":"Journal of medicinal chemistry","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro binding assay confirmed by cell-based functional selectivity, single lab","pmids":["29860841"],"is_preprint":false},{"year":2023,"finding":"In NPM1-mutated AML, mislocalized NPM1-mA in the cytoplasm binds E3 ubiquitin ligase MID1 to block ubiquitin-dependent degradation of RasGRP3, thereby stabilizing RasGRP3 protein. Elevated RasGRP3 then activates the EGFR-STAT3 axis to promote AML cell proliferation and autophagy.","method":"Co-immunoprecipitation, Western blot, cycloheximide chase assay (protein stability), CCK8/EdU proliferation assay, immunofluorescence","journal":"Journal of leukocyte biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP and protein stability assay define mechanism of RasGRP3 stabilization; single lab, single study","pmids":["36826998"],"is_preprint":false},{"year":2023,"finding":"In colorectal cancer, the lncRNA AC092894.1 acts as a scaffold to mediate USP3-dependent de-ubiquitination and stabilization of the androgen receptor (AR), which then transcriptionally activates RASGRP3 expression, sustaining MAPK signaling and sensitizing cells to oxaliplatin. RASGRP3 thus functions downstream of an AR transcriptional program whose activity is regulated by protein ubiquitination.","method":"RNA pull-down, RIP assay, co-immunoprecipitation, gain/loss-of-function experiments","journal":"BMC medicine","confidence":"Low","confidence_rationale":"Tier 3 / Weak — indirect: RasGRP3 is positioned downstream of AR transcription in this study; primary mechanism concerns the lncRNA/USP3/AR axis rather than RasGRP3 itself; single lab","pmids":["37013584"],"is_preprint":false},{"year":2026,"finding":"In endothelial cells, RasGRP3 overexpression activates RAP1B and inhibits NF-κB pathway activation and pro-inflammatory cytokine production; endothelial-specific RasGRP3 overexpression in ApoE-/- mice reduces atherosclerotic plaque formation. UHRF1, an E3 ubiquitin ligase family member, is identified as a RasGRP3-binding protein; UHRF1 knockdown inhibits ubiquitination and degradation of RasGRP3, promoting its protein expression.","method":"Overexpression in endothelial cells, Rap1 activity assay, NF-κB pathway assay, endothelial-specific transgenic ApoE-/- mouse model, co-immunoprecipitation (UHRF1-RasGRP3 interaction), ubiquitination assay","journal":"Inflammation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo mouse model plus in vitro mechanistic studies with co-IP and ubiquitination assay; single lab, recent publication","pmids":["41689678"],"is_preprint":false}],"current_model":"RasGRP3 (CalDAG-GEFIII) is a diacylglycerol/phorbol ester-regulated guanine nucleotide exchange factor that activates Ha-Ras, R-Ras, and Rap1 GTPases; it is recruited to membranes via its C1 domain upon DAG/phorbol ester binding and is additionally activated by PKC-dependent phosphorylation on Thr133 (downstream of PLC-gamma/DAG in B cells and PKCδ/ε in uveal melanoma), with c-Src providing a third activation input (Tyr phosphorylation) downstream of receptor tyrosine kinases; its subcellular localization is further regulated through interaction with dynein light chain 1 and Arp3; downstream consequences include ERK/MAPK and AKT pathway activation, Rap1-mediated suppression of inflammatory signaling in macrophages and endothelial cells, and PKC-independent exocytosis, with essential roles established in BCR-mediated B cell proliferation, GNAQ/GNA11-driven uveal melanoma Ras signaling, endothelial angiogenesis, and glioma cell migration."},"narrative":{"mechanistic_narrative":"RASGRP3 (CalDAG-GEFIII) is a diacylglycerol/phorbol-ester-regulated guanine nucleotide exchange factor that couples receptor-driven lipid second-messenger signaling to small-GTPase activation, exchanging GDP for GTP on Ha-Ras, R-Ras and Rap1 with broader substrate specificity than its CalDAG-GEF relatives [PMID:10835426]. Its C1 domain binds phorbol esters in an anionic-phospholipid-dependent manner, and ligand binding both stimulates exchange activity and redistributes RASGRP3 to plasma and intracellular membranes, defining it as a PKC-independent phorbol-ester receptor that links DAG to Ras-ERK activation [PMID:11221888, PMID:15657361]. RASGRP3 is subject to dual regulation: in addition to DAG-driven membrane recruitment, PKC phosphorylates it specifically on Thr133 to achieve full Ras-activating capacity, a step required downstream of PLC-gamma2/BCR signaling in B cells and mediated by PKC isoforms including PKC-theta, PKC-beta2 and PKC-delta [PMID:12730099, PMID:15657177, PMID:15545601, PMID:15213298]; a parallel input occurs via c-Src-dependent tyrosine phosphorylation downstream of the EGF receptor, routing signaling through Rap2B to PLC-epsilon [PMID:15143162]. Genetic loss-of-function establishes RASGRP3 as essential for BCR-induced B cell proliferation and humoral immunity [PMID:16301621], for DAG-dependent endothelial morphogenesis and endothelin-1-driven endothelial migration [PMID:15572660, PMID:21474816], and as the critical node activating Ras downstream of oncogenic GNAQ/GNA11 in uveal melanoma, where it is engaged both by PKC-delta/epsilon phosphorylation and by DAG-mediated recruitment [PMID:28486107, PMID:29490280]. Through activation of Rap1/RAP1B, RASGRP3 also restrains inflammatory signaling, limiting TLR-induced IL-6 production in macrophages and suppressing NF-kappaB activation in endothelial cells [PMID:25118589, PMID:41689678]. Its subcellular localization is shaped by interactions with dynein light chain 1 (DLC1), which anchors it via its C-terminal region, and with Arp3, which links it to actin-dependent glioma cell migration [PMID:17012239, PMID:25682201]; RASGRP3 protein levels are additionally controlled by ubiquitin-dependent degradation involving the E3 ligase family members MID1 and UHRF1 [PMID:36826998, PMID:41689678].","teleology":[{"year":2000,"claim":"Established the core biochemical identity of RASGRP3 as a GEF, answering which GTPases it acts on and distinguishing it from related family members.","evidence":"In vitro GEF assay with multiple GTPase substrates plus PC12 differentiation and Rat1A transformation assays","pmids":["10835426"],"confidence":"High","gaps":["Structural basis of substrate selectivity unresolved","Physiological receptor inputs not yet defined"]},{"year":2001,"claim":"Defined how RASGRP3 senses lipid second messengers, showing C1-domain phorbol ester binding activates exchange activity and drives membrane redistribution.","evidence":"Phorbol ester binding assay, Ras-GTP pull-down, GFP-RASGRP3 live-cell imaging in HEK-293 cells","pmids":["11221888"],"confidence":"High","gaps":["Identity of physiological DAG-generating receptors not addressed","Quantitative coupling of membrane recruitment to exchange rate unclear"]},{"year":2003,"claim":"Revealed a second layer of regulation beyond membrane recruitment, showing PKC phosphorylates RASGRP3 coincident with Ras activation.","evidence":"In vitro kinase assay with PKC-theta/PKC-beta2, co-IP, pharmacological PKC inhibition and fractionation in B cells","pmids":["12730099"],"confidence":"High","gaps":["Specific phosphosite not yet mapped","Relative contribution of phosphorylation vs recruitment not quantified"]},{"year":2004,"claim":"Pinpointed Thr133 as the PKC phosphosite functionally linking PKC to Ras activation downstream of the BCR, converting a correlative observation into a defined mechanistic step.","evidence":"MS phosphosite mapping, Thr133Ala mutagenesis, phospho-specific antibody, PLC-gamma2 deletion and PKC inhibition in B cells","pmids":["15657177","15545601"],"confidence":"High","gaps":["Whether other sites contribute to full activation unknown","Structural consequence of Thr133 phosphorylation undefined"]},{"year":2004,"claim":"Expanded the regulatory kinase repertoire by showing PKC-delta physically associates with and phosphorylates RASGRP3, modulating localization and ERK output.","evidence":"Co-IP, in vitro kinase assay, PKC-delta kinase-dead mutant, rottlerin inhibition, colocalization","pmids":["15213298"],"confidence":"High","gaps":["Serine sites phosphorylated by PKC-delta not mapped","Functional interplay with Thr133 phosphorylation unresolved"]},{"year":2004,"claim":"Identified a tyrosine-phosphorylation activation input, placing RASGRP3 in an EGFR-c-Src-Rap2B-PLC-epsilon axis distinct from the DAG/PKC route.","evidence":"Reciprocal co-IP, dominant-negative Rap2B, c-Src inhibition, GTP-loading and Ca2+ measurement in HEK-293 cells","pmids":["15143162"],"confidence":"Medium","gaps":["c-Src tyrosine target site on RASGRP3 not mapped","Single-lab finding without genetic validation"]},{"year":2005,"claim":"Defined RASGRP3's physiological role in adaptive immunity, showing it sustains basal Ras-GTP and is required for BCR-induced proliferation and humoral responses.","evidence":"Rasgrp1/Rasgrp3 single and double knockout mice, Ras-GTP pull-down, proliferation and in vivo immunization assays","pmids":["16301621"],"confidence":"High","gaps":["Molecular basis of redundancy with RASGRP1 not dissected","Downstream effector pathway in B cells not fully mapped"]},{"year":2005,"claim":"Clarified that RASGRP3 translocation tracks ligand localization and supports a PKC-independent output (exocytosis), broadening its functional scope beyond Ras-ERK.","evidence":"Live-cell imaging with fluorescent phorbol esters/GFP fusions in CHO cells; exocytosis assay with PKC/MEK inhibition in endocrine cells","pmids":["15657361","15737652"],"confidence":"Medium","gaps":["Molecular mechanism coupling RASGRP3 GEF activity to exocytosis not identified","Exocytosis finding is low-confidence single functional assay"]},{"year":2006,"claim":"Identified DLC1 as an anchoring partner controlling RASGRP3 subcellular distribution via its C-terminus, explaining a determinant of localization independent of ligand binding.","evidence":"Yeast two-hybrid screen, in vitro pull-down, co-IP, C-terminal truncation mutagenesis, fluorescence localization","pmids":["17012239"],"confidence":"Medium","gaps":["Functional consequence of DLC1 anchoring for GEF activity not measured","Single-lab interaction"]},{"year":2011,"claim":"Established RASGRP3 in endothelial pathophysiology, placing it in an endothelin-1-Ras/MEK/ERK axis required for migration and for diabetes-induced vascular defects.","evidence":"Rasgrp3 loss-of-function embryos from diabetic mothers, activated RASGRP3 overexpression in primary endothelial cells, migration and signaling assays","pmids":["21474816","15572660"],"confidence":"Medium","gaps":["Receptor-proximal coupling of endothelin-1 to RASGRP3 not detailed","Single-lab models"]},{"year":2014,"claim":"Showed RASGRP3 sets an anti-inflammatory threshold via Rap1, distinguishing its Rap1 output from ERK and revealing a restraining role in innate immune signaling.","evidence":"CRISPR-Cas9 RASGRP3 knockout in RAW264.7 cells, Rap1-GTP pull-down, IL-6 measurement, in vivo colitis/arthritis models","pmids":["25118589"],"confidence":"High","gaps":["How Rap1 mechanistically dampens TLR-ERK/IL-6 not fully resolved","Receptor-proximal activation of RASGRP3 by TLRs unclear"]},{"year":2015,"claim":"Linked RASGRP3 to the actin machinery through Arp3, providing a mechanism for its role in glioma migration and invasion beyond GTPase exchange.","evidence":"Pull-down/MS, co-IP, immunofluorescence, Arp3 siRNA, migration/invasion assays in glioma cells","pmids":["25682201"],"confidence":"Medium","gaps":["Whether RASGRP3-Arp3 interaction is direct or scaffolded unclear","Single-lab finding"]},{"year":2018,"claim":"Identified RASGRP3 as the essential node coupling oncogenic GNAQ/GNA11 to Ras-MAPK in uveal melanoma, integrating both PKC-dependent and DAG-dependent activation modes.","evidence":"siRNA/shRNA knockdown, PKC inhibition, Ras-GTP pull-down in UM cell lines, GNA11Q209L mouse model, transcriptome and xenograft analyses","pmids":["28486107","29490280"],"confidence":"High","gaps":["Mechanism of GNAQ/11-driven RASGRP3 overexpression not fully defined","Therapeutic exploitability of dual activation modes not resolved"]},{"year":2018,"claim":"Demonstrated that the RASGRP3 C1 domain is pharmacologically targetable with selectivity over PKC, establishing a chemical-biology entry point.","evidence":"In vitro C1-domain competitive binding assay and cell-based Ras-GTP/PKC-delta phosphorylation selectivity with DAG-lactone compound 96","pmids":["29860841"],"confidence":"Medium","gaps":["In vivo efficacy and pharmacology of the ligand untested","Single-lab in vitro selectivity data"]},{"year":2023,"claim":"Revealed post-translational control of RASGRP3 abundance, showing ubiquitin-dependent degradation modulated by the E3 ligase MID1 governs RASGRP3 stability in NPM1-mutant AML.","evidence":"Co-IP, cycloheximide chase, proliferation assays in NPM1-mutated AML cells","pmids":["36826998"],"confidence":"Medium","gaps":["Direct ubiquitination of RASGRP3 by MID1 not demonstrated","Single-lab finding"]},{"year":2026,"claim":"Reinforced the anti-inflammatory Rap1B output in vascular disease and identified a second E3-ligase-family regulator (UHRF1) controlling RASGRP3 protein turnover.","evidence":"Endothelial overexpression, Rap1 activity and NF-kappaB assays, endothelial-specific ApoE-/- transgenic mice, co-IP and ubiquitination assay","pmids":["41689678"],"confidence":"Medium","gaps":["Whether UHRF1 directly ubiquitinates RASGRP3 not fully established","Single-lab recent finding"]},{"year":null,"claim":"How the multiple activation inputs (DAG recruitment, Thr133/Ser PKC phosphorylation, c-Src tyrosine phosphorylation) and degradation pathways are integrated to bias RASGRP3 toward Ras versus Rap1 outputs in a given cell type remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model integrating C1, GEF and regulatory phosphosites","No unified quantitative model of Ras-vs-Rap1 output selection","Mechanism directing substrate choice across cell types unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[1,9]},{"term_id":"GO:0060089","term_label":"molecular transducer activity","supporting_discovery_ids":[0,16]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,2,9]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[11]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,16]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[8,14]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[16,17]}],"complexes":[],"partners":["DLC1","ARP3","PRKCD","PRKCQ","SRC","MID1","UHRF1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8IV61","full_name":"Ras guanyl-releasing protein 3","aliases":["Calcium and DAG-regulated guanine nucleotide exchange factor III","Guanine nucleotide exchange factor for Rap1"],"length_aa":690,"mass_kda":78.3,"function":"Guanine nucleotide exchange factor (GEF) for Ras and Rap1","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/Q8IV61/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RASGRP3","classification":"Not Classified","n_dependent_lines":10,"n_total_lines":1208,"dependency_fraction":0.008278145695364239},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RASGRP3","total_profiled":1310},"omim":[{"mim_id":"609531","title":"RAS GUANYL NUCLEOTIDE-RELEASING PROTEIN 3; RASGRP3","url":"https://www.omim.org/entry/609531"},{"mim_id":"607320","title":"RAS GUANYL NUCLEOTIDE-RELEASING PROTEIN 4; RASGRP4","url":"https://www.omim.org/entry/607320"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Cytosol","reliability":"Approved"},{"location":"Golgi apparatus","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":47.4},{"tissue":"skeletal 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\"CalDAG-GEFIII (RasGRP3) is a guanine nucleotide exchange factor that promotes GDP-to-GTP exchange on Ha-Ras, R-Ras, and Rap1 both in intact cells and in vitro, exhibiting broader substrate specificity than related family members CalDAG-GEFI and CalDAG-GEFII. Expression of RasGRP3 activates ERK/MAPK, and co-activation of Rap1 by RasGRP3 attenuates Ras-MAPK-dependent neuronal differentiation and cellular transformation.\",\n      \"method\": \"In vitro GEF assay (GTP/GDP ratio measurement), transfection in 293T cells, PC12 neuronal differentiation assay, Rat1A anchorage-independent growth assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro GEF reconstitution with multiple GTPase substrates, complemented by cell-based functional assays\",\n      \"pmids\": [\"10835426\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"RasGRP3 binds phorbol esters with high affinity via its C1 domain in an anionic phospholipid-dependent manner, and phorbol ester binding activates RasGRP3 exchange activity (increasing Ras-GTP and ERK phosphorylation) and causes redistribution of RasGRP3 to the plasma membrane and/or perinuclear area, identifying RasGRP3 as a PKC-independent phorbol ester receptor linking DAG/phorbol ester signaling to Ras activation.\",\n      \"method\": \"Phorbol ester binding assay, Ras-GTP pull-down, ERK phosphorylation (Western blot), GFP-RasGRP3 live-cell imaging/redistribution in HEK-293 cells\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct ligand-binding assay plus functional GEF activation and subcellular redistribution, replicated across multiple methods in one study and consistent with subsequent papers\",\n      \"pmids\": [\"11221888\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"RasGRP3 is phosphorylated coincident with Ras activation after PMA stimulation of B cells; PKC inhibitors attenuate both Ras activation and RasGRP3 phosphorylation. PKC-theta and PKC-beta2 phosphorylate RasGRP3 in vitro, and a dominant-active PKC-theta mutant co-expressed with RasGRP3 in HEK-293 cells enhances Ras-ERK signaling. PMA also induces membrane association of RasGRP3, indicating dual regulation by DAG-mediated membrane recruitment and PKC-dependent phosphorylation.\",\n      \"method\": \"In vitro kinase assay with PKC-theta and PKC-beta2, co-immunoprecipitation, Ras-GTP pull-down, pharmacological PKC inhibition, subcellular fractionation\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro kinase assay plus cell-based pharmacological dissection, two independent orthogonal approaches, consistent with multiple subsequent studies\",\n      \"pmids\": [\"12730099\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"PKC phosphorylates RasGRP3 specifically on threonine 133 (identified by mass spectrometry in vitro). A Thr133Ala substitution renders RasGRP3 a poor PKC substrate in vitro and a poor Ras activator in vivo. Anti-phospho-Thr133 antibodies detect phosphorylated RasGRP3 in B cells after BCR stimulation or DAG analog treatment; PKC inhibitors block both Thr133 phosphorylation and Ras-ERK signaling. This defines Thr133 phosphorylation as a mechanistic link between PKC and Ras activation downstream of BCR signaling.\",\n      \"method\": \"In vitro kinase assay with mass spectrometry (Thr133 identification), site-directed mutagenesis (Thr133Ala), anti-phosphopeptide antibody, pharmacological PKC inhibition, Ras-GTP pull-down in B cells\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — MS-identified phosphosite, mutagenesis validation, antibody confirmation in cells; independently replicated by Aiba et al. 2004 (PMID 15545601)\",\n      \"pmids\": [\"15657177\", \"15545601\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"RasGRP3 Thr133 is phosphorylated upon BCR cross-linking; deletion of PLC-gamma2 or pharmacological inhibition of conventional PKCs markedly reduces both Thr133 phosphorylation and Ras activation. Thr133Ala mutation severely impairs RasGRP3-mediated Ras activation in BCR signaling, indicating that PKC (activated by DAG downstream of PLC-gamma2) phosphorylates RasGRP3 at Thr133 to achieve full activation.\",\n      \"method\": \"BCR cross-linking, pharmacological PKC inhibition, Thr133Ala mutagenesis, Ras activation assay in B cell lines\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — mutagenesis and genetic (PLC-gamma2 deletion) combined with pharmacological approach; independently corroborates PMID 15657177\",\n      \"pmids\": [\"15545601\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"PKCdelta physically associates with RasGRP3 upon PMA stimulation, as shown by co-immunoprecipitation and co-localization in the perinuclear region. PKCdelta phosphorylates RasGRP3 in vitro (on serine residues). A PKCdelta kinase-dead mutant blocks the PMA-induced mobility shift of RasGRP3. Co-expression of PKCdelta and RasGRP3 modulates Erk1/2 activation compared with either alone.\",\n      \"method\": \"Co-immunoprecipitation, in vitro kinase assay, kinase-dead mutant expression, pharmacological inhibition (rottlerin), immunofluorescence colocalization\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro kinase assay + co-IP + mutagenesis, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"15213298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"EGF receptor activates Rap2B-dependent stimulation of PLC-epsilon through RasGRP3: EGF induces tyrosine phosphorylation of RasGRP3 (but not RasGRP1) by c-Src; inhibition of c-Src blocks EGF-induced Rap2B-GTP loading and PLC-epsilon stimulation. RasGRP3 overexpression enhances GTP loading of Rap2B and PLC/Ca2+ signaling by EGF receptor, establishing a pathway: EGF receptor → c-Src → RasGRP3 (Tyr phosphorylation) → Rap2B → PLC-epsilon.\",\n      \"method\": \"Co-immunoprecipitation (Rap2B-PLC-epsilon), dominant-negative Rap2B expression, c-Src pharmacological inhibition, RasGRP3 overexpression, Ca2+ signaling measurement, GTP-loading assay in HEK-293 cells\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus pharmacological epistasis and overexpression, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"15143162\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"RasGRP3 is expressed in embryonic blood vessels, downregulated in mature vessels, and re-expressed in angiogenic vessels during pregnancy and tumorigenesis. RasGRP3 is upregulated downstream of VEGF stimulation in HUVECs. In ES cell-derived vascular models, loss of RasGRP3 abolishes phorbol ester (PMA)-induced aberrant endothelial morphogenesis (formation of large sheets rather than branched vessels), establishing RasGRP3 as a required endothelial phorbol ester receptor mediating DAG-dependent angiogenic responses.\",\n      \"method\": \"Gene trap loss-of-function mouse model, ES cell vascular differentiation assay, PMA treatment, RT-PCR/in situ hybridization for expression pattern\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic loss-of-function with defined morphogenetic phenotype, single lab\",\n      \"pmids\": [\"15572660\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"RasGRP1 and RasGRP3 both contribute to BCR-induced Ras-GTP generation in B cells, with RasGRP3 alone responsible for maintaining basal Ras-GTP levels in unstimulated B cells. Double-null mutant mice show no defect in B cell development, but loss of RasGRP3 leads to humoral deficiencies (hypogammaglobulinemia, isotype-specific Ab induction defects) and loss of BCR-induced B cell proliferation. RasGRP-independent pathways support LPS-induced proliferation.\",\n      \"method\": \"Single and double Rasgrp1/Rasgrp3 knock-out mice, Ras-GTP pull-down, B cell proliferation assay, in vivo immunization, serum Ig measurement\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean genetic double KO with multiple functional readouts (Ras-GTP, proliferation, humoral immunity in vivo)\",\n      \"pmids\": [\"16301621\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Fluorescent phorbol esters and complementary GFP-RasGRP3 fusion constructs showed that RasGRP3 co-localizes with and translocates to intracellular membranes upon phorbol ester treatment, with translocation pattern following ligand localization. The rate of phorbol ester uptake influences the pattern of RasGRP3 translocation.\",\n      \"method\": \"Live-cell fluorescence imaging with fluorescently labeled phorbol esters and GFP/DsRed fusion constructs for RasGRP3 in CHO cells\",\n      \"journal\": \"Molecular cancer therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct live-cell imaging of localization dynamics with functional implication, single lab\",\n      \"pmids\": [\"15657361\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"RasGRP3 is expressed in endocrine tissues and mediates phorbol ester-induced exocytosis in a PKC-independent manner; this effect was partially blocked by PKC inhibitors but not MEK inhibitor, despite MEK inhibitor blocking phorbol ester-induced ERK1/2 phosphorylation.\",\n      \"method\": \"Exocytosis assay in endocrine cells, pharmacological inhibition of PKC and MEK, ERK1/2 phosphorylation (Western blot)\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single functional assay without molecular identification of GEF-exocytosis mechanism\",\n      \"pmids\": [\"15737652\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Dynein light chain 1 (DLC1) is a novel RasGRP3-interacting protein identified by yeast two-hybrid screening of a human brain cDNA library and confirmed by in vitro pull-down and co-immunoprecipitation. The interaction requires the C-terminal 127 amino acids of RasGRP3. A truncated RasGRP3 lacking this C-terminal domain cannot interact with DLC1 and displays dramatically altered subcellular localization (strong reticular distribution with perinuclear and nuclear accumulation), suggesting DLC1 acts as an anchoring protein regulating RasGRP3 subcellular localization.\",\n      \"method\": \"Yeast two-hybrid screen, in vitro pull-down, co-immunoprecipitation, C-terminal truncation mutagenesis, subcellular localization by fluorescence microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid confirmed by in vitro and in vivo binding, mutagenesis defines interaction domain and functional consequence on localization; single lab\",\n      \"pmids\": [\"17012239\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"In prostate cancer cell lines, RasGRP3 maintains Ras-GTP formation; siRNA knockdown reduces Ras-GTP, AKT phosphorylation, and ERK1/2 phosphorylation, inhibits proliferation, migration, and anchorage-independent growth, and induces apoptosis and sensitizes cells to carboplatin. Ectopic RasGRP3 expression in LNCaP cells elevates Ras-GTP and stimulates proliferation, defining RasGRP3 as an upstream activator of both AKT and ERK pathways in prostate cancer.\",\n      \"method\": \"siRNA knockdown, Ras-GTP pull-down, AKT/ERK phosphorylation (Western blot), proliferation assay, migration assay, soft-agar colony formation, xenograft mouse model\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss- and gain-of-function with multiple downstream pathway readouts, single lab\",\n      \"pmids\": [\"20876802\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"RasGRP3 mediates diabetes-induced vascular developmental defects: embryos lacking Rasgrp3 function show dramatically attenuated diabetes-induced developmental defects. Endothelial cells expressing activated RasGRP3 have elevated Ras-ERK signaling and perturbed migration; cells lacking Rasgrp3 have attenuated Ras-ERK signaling and fail to migrate in response to endothelin-1. This establishes RasGRP3 in a pathway: endothelin-1 (upstream input) → RasGRP3 → Ras/MEK/ERK → endothelial migration.\",\n      \"method\": \"Rasgrp3 loss-of-function mouse embryos from diabetic mothers, activated RasGRP3 overexpression in primary endothelial cells, endothelin-1 stimulation, Ras-ERK signaling (Western blot), endothelial migration assay\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function in vivo combined with gain/loss in primary cells with defined signaling readouts; single lab\",\n      \"pmids\": [\"21474816\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"RasGRP3 activates Rap1 in macrophages downstream of TLR3/4/9 stimulation. In RasGRP3-deficient RAW264.7 cells (generated by CRISPR-Cas9), TLR-induced Rap1 activation is inhibited while ERK1/2 activation is enhanced. RasGRP3 thus limits IL-6 production in macrophages exposed to low levels of TLR agonists by activating Rap1, setting a threshold for inflammatory responses.\",\n      \"method\": \"CRISPR-Cas9 knockout of RasGRP3 in RAW264.7 cells, Rap1-GTP pull-down, ERK1/2 phosphorylation (Western blot), IL-6 cytokine measurement, in vivo colitis and arthritis models\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — CRISPR KO with direct GTPase activation assay (Rap1-GTP), multiple TLR stimuli, and in vivo disease models in same study\",\n      \"pmids\": [\"25118589\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"RasGRP3 interacts with Arp3 (actin-related protein 3) in glioma cells, identified by pull-down/mass spectrometry and validated by co-immunoprecipitation and immunofluorescence. PMA-induced translocation of RasGRP3 to the perinuclear region increases its association with Arp3. Silencing Arp3 partially abrogates RasGRP3-induced glioma cell migration and invasion, linking RasGRP3 to actin polymerization-dependent cell motility.\",\n      \"method\": \"Pull-down assay with mass spectrometry, co-immunoprecipitation, immunofluorescence, siRNA knockdown, cell migration/invasion assay\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — MS-identified interaction confirmed by co-IP and localization, functional epistasis by Arp3 knockdown; single lab\",\n      \"pmids\": [\"25682201\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"In GNAQ/GNA11 mutant uveal melanoma, MAPK activation requires Ras and is caused by RasGRP3, which is selectively overexpressed in response to GNAQ/11 mutation. PKCδ and PKCε are required and sufficient for MAPK activation upstream of RasGRP3. RasGRP3 is activated by two mechanisms: PKCδ/ε-dependent phosphorylation and PKC-independent DAG-mediated membrane recruitment, explaining the limited durability of PKC inhibitor effects on MAPK suppression.\",\n      \"method\": \"siRNA/shRNA knockdown, pharmacological PKC inhibition, Ras-GTP pull-down, ERK phosphorylation (Western blot), reconstitution of signaling in cell lines, expression analysis in human UM samples\",\n      \"journal\": \"Cancer cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — mechanistic dissection with loss-of-function (siRNA) and pharmacological epistasis in multiple UM cell lines, two activation mechanisms defined; replicated independently (PMID 29490280)\",\n      \"pmids\": [\"28486107\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In a GNA11Q209L mouse model of uveal melanoma, RasGRP3 is specifically expressed in GNAQ/GNA11-driven melanomas (identified by integrative transcriptome analysis). In human UM cell lines and murine models, RasGRP3 is specifically required for GNAQ/GNA11-driven Ras activation and tumorigenesis, confirming RasGRP3 as an essential node in the Gαq/11 → Ras signaling axis.\",\n      \"method\": \"GNA11Q209L knock-in mouse model, transcriptome analysis (human and murine melanomas), siRNA/shRNA knockdown in human UM cell lines, Ras-GTP pull-down, xenograft tumorigenesis assay\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic mouse model plus human cell line loss-of-function with direct Ras-GTP measurement; independently corroborates PMID 28486107\",\n      \"pmids\": [\"29490280\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"DAG-lactone compound 96 shows 73-fold selectivity for RasGRP3 versus PKCα and 45-fold versus PKCε in C1-domain binding assays in vitro, and in intact cells induces Ras activation (downstream of RasGRP) with 8–29-fold selectivity relative to PKCδ phosphorylation, establishing that selective RasGRP3 C1-domain targeting is achievable with this ligand scaffold.\",\n      \"method\": \"In vitro C1-domain competitive binding assay, cell-based Ras-GTP and PKCδ phosphorylation assay\",\n      \"journal\": \"Journal of medicinal chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro binding assay confirmed by cell-based functional selectivity, single lab\",\n      \"pmids\": [\"29860841\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In NPM1-mutated AML, mislocalized NPM1-mA in the cytoplasm binds E3 ubiquitin ligase MID1 to block ubiquitin-dependent degradation of RasGRP3, thereby stabilizing RasGRP3 protein. Elevated RasGRP3 then activates the EGFR-STAT3 axis to promote AML cell proliferation and autophagy.\",\n      \"method\": \"Co-immunoprecipitation, Western blot, cycloheximide chase assay (protein stability), CCK8/EdU proliferation assay, immunofluorescence\",\n      \"journal\": \"Journal of leukocyte biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP and protein stability assay define mechanism of RasGRP3 stabilization; single lab, single study\",\n      \"pmids\": [\"36826998\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"In colorectal cancer, the lncRNA AC092894.1 acts as a scaffold to mediate USP3-dependent de-ubiquitination and stabilization of the androgen receptor (AR), which then transcriptionally activates RASGRP3 expression, sustaining MAPK signaling and sensitizing cells to oxaliplatin. RASGRP3 thus functions downstream of an AR transcriptional program whose activity is regulated by protein ubiquitination.\",\n      \"method\": \"RNA pull-down, RIP assay, co-immunoprecipitation, gain/loss-of-function experiments\",\n      \"journal\": \"BMC medicine\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — indirect: RasGRP3 is positioned downstream of AR transcription in this study; primary mechanism concerns the lncRNA/USP3/AR axis rather than RasGRP3 itself; single lab\",\n      \"pmids\": [\"37013584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In endothelial cells, RasGRP3 overexpression activates RAP1B and inhibits NF-κB pathway activation and pro-inflammatory cytokine production; endothelial-specific RasGRP3 overexpression in ApoE-/- mice reduces atherosclerotic plaque formation. UHRF1, an E3 ubiquitin ligase family member, is identified as a RasGRP3-binding protein; UHRF1 knockdown inhibits ubiquitination and degradation of RasGRP3, promoting its protein expression.\",\n      \"method\": \"Overexpression in endothelial cells, Rap1 activity assay, NF-κB pathway assay, endothelial-specific transgenic ApoE-/- mouse model, co-immunoprecipitation (UHRF1-RasGRP3 interaction), ubiquitination assay\",\n      \"journal\": \"Inflammation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo mouse model plus in vitro mechanistic studies with co-IP and ubiquitination assay; single lab, recent publication\",\n      \"pmids\": [\"41689678\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RasGRP3 (CalDAG-GEFIII) is a diacylglycerol/phorbol ester-regulated guanine nucleotide exchange factor that activates Ha-Ras, R-Ras, and Rap1 GTPases; it is recruited to membranes via its C1 domain upon DAG/phorbol ester binding and is additionally activated by PKC-dependent phosphorylation on Thr133 (downstream of PLC-gamma/DAG in B cells and PKCδ/ε in uveal melanoma), with c-Src providing a third activation input (Tyr phosphorylation) downstream of receptor tyrosine kinases; its subcellular localization is further regulated through interaction with dynein light chain 1 and Arp3; downstream consequences include ERK/MAPK and AKT pathway activation, Rap1-mediated suppression of inflammatory signaling in macrophages and endothelial cells, and PKC-independent exocytosis, with essential roles established in BCR-mediated B cell proliferation, GNAQ/GNA11-driven uveal melanoma Ras signaling, endothelial angiogenesis, and glioma cell migration.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RASGRP3 (CalDAG-GEFIII) is a diacylglycerol/phorbol-ester-regulated guanine nucleotide exchange factor that couples receptor-driven lipid second-messenger signaling to small-GTPase activation, exchanging GDP for GTP on Ha-Ras, R-Ras and Rap1 with broader substrate specificity than its CalDAG-GEF relatives [#0]. Its C1 domain binds phorbol esters in an anionic-phospholipid-dependent manner, and ligand binding both stimulates exchange activity and redistributes RASGRP3 to plasma and intracellular membranes, defining it as a PKC-independent phorbol-ester receptor that links DAG to Ras-ERK activation [#1, #9]. RASGRP3 is subject to dual regulation: in addition to DAG-driven membrane recruitment, PKC phosphorylates it specifically on Thr133 to achieve full Ras-activating capacity, a step required downstream of PLC-gamma2/BCR signaling in B cells and mediated by PKC isoforms including PKC-theta, PKC-beta2 and PKC-delta [#2, #3, #4, #5]; a parallel input occurs via c-Src-dependent tyrosine phosphorylation downstream of the EGF receptor, routing signaling through Rap2B to PLC-epsilon [#6]. Genetic loss-of-function establishes RASGRP3 as essential for BCR-induced B cell proliferation and humoral immunity [#8], for DAG-dependent endothelial morphogenesis and endothelin-1-driven endothelial migration [#7, #13], and as the critical node activating Ras downstream of oncogenic GNAQ/GNA11 in uveal melanoma, where it is engaged both by PKC-delta/epsilon phosphorylation and by DAG-mediated recruitment [#16, #17]. Through activation of Rap1/RAP1B, RASGRP3 also restrains inflammatory signaling, limiting TLR-induced IL-6 production in macrophages and suppressing NF-kappaB activation in endothelial cells [#14, #21]. Its subcellular localization is shaped by interactions with dynein light chain 1 (DLC1), which anchors it via its C-terminal region, and with Arp3, which links it to actin-dependent glioma cell migration [#11, #15]; RASGRP3 protein levels are additionally controlled by ubiquitin-dependent degradation involving the E3 ligase family members MID1 and UHRF1 [#19, #21].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established the core biochemical identity of RASGRP3 as a GEF, answering which GTPases it acts on and distinguishing it from related family members.\",\n      \"evidence\": \"In vitro GEF assay with multiple GTPase substrates plus PC12 differentiation and Rat1A transformation assays\",\n      \"pmids\": [\"10835426\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of substrate selectivity unresolved\", \"Physiological receptor inputs not yet defined\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Defined how RASGRP3 senses lipid second messengers, showing C1-domain phorbol ester binding activates exchange activity and drives membrane redistribution.\",\n      \"evidence\": \"Phorbol ester binding assay, Ras-GTP pull-down, GFP-RASGRP3 live-cell imaging in HEK-293 cells\",\n      \"pmids\": [\"11221888\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of physiological DAG-generating receptors not addressed\", \"Quantitative coupling of membrane recruitment to exchange rate unclear\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Revealed a second layer of regulation beyond membrane recruitment, showing PKC phosphorylates RASGRP3 coincident with Ras activation.\",\n      \"evidence\": \"In vitro kinase assay with PKC-theta/PKC-beta2, co-IP, pharmacological PKC inhibition and fractionation in B cells\",\n      \"pmids\": [\"12730099\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific phosphosite not yet mapped\", \"Relative contribution of phosphorylation vs recruitment not quantified\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Pinpointed Thr133 as the PKC phosphosite functionally linking PKC to Ras activation downstream of the BCR, converting a correlative observation into a defined mechanistic step.\",\n      \"evidence\": \"MS phosphosite mapping, Thr133Ala mutagenesis, phospho-specific antibody, PLC-gamma2 deletion and PKC inhibition in B cells\",\n      \"pmids\": [\"15657177\", \"15545601\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether other sites contribute to full activation unknown\", \"Structural consequence of Thr133 phosphorylation undefined\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Expanded the regulatory kinase repertoire by showing PKC-delta physically associates with and phosphorylates RASGRP3, modulating localization and ERK output.\",\n      \"evidence\": \"Co-IP, in vitro kinase assay, PKC-delta kinase-dead mutant, rottlerin inhibition, colocalization\",\n      \"pmids\": [\"15213298\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Serine sites phosphorylated by PKC-delta not mapped\", \"Functional interplay with Thr133 phosphorylation unresolved\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identified a tyrosine-phosphorylation activation input, placing RASGRP3 in an EGFR-c-Src-Rap2B-PLC-epsilon axis distinct from the DAG/PKC route.\",\n      \"evidence\": \"Reciprocal co-IP, dominant-negative Rap2B, c-Src inhibition, GTP-loading and Ca2+ measurement in HEK-293 cells\",\n      \"pmids\": [\"15143162\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"c-Src tyrosine target site on RASGRP3 not mapped\", \"Single-lab finding without genetic validation\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined RASGRP3's physiological role in adaptive immunity, showing it sustains basal Ras-GTP and is required for BCR-induced proliferation and humoral responses.\",\n      \"evidence\": \"Rasgrp1/Rasgrp3 single and double knockout mice, Ras-GTP pull-down, proliferation and in vivo immunization assays\",\n      \"pmids\": [\"16301621\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of redundancy with RASGRP1 not dissected\", \"Downstream effector pathway in B cells not fully mapped\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Clarified that RASGRP3 translocation tracks ligand localization and supports a PKC-independent output (exocytosis), broadening its functional scope beyond Ras-ERK.\",\n      \"evidence\": \"Live-cell imaging with fluorescent phorbol esters/GFP fusions in CHO cells; exocytosis assay with PKC/MEK inhibition in endocrine cells\",\n      \"pmids\": [\"15657361\", \"15737652\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular mechanism coupling RASGRP3 GEF activity to exocytosis not identified\", \"Exocytosis finding is low-confidence single functional assay\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Identified DLC1 as an anchoring partner controlling RASGRP3 subcellular distribution via its C-terminus, explaining a determinant of localization independent of ligand binding.\",\n      \"evidence\": \"Yeast two-hybrid screen, in vitro pull-down, co-IP, C-terminal truncation mutagenesis, fluorescence localization\",\n      \"pmids\": [\"17012239\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of DLC1 anchoring for GEF activity not measured\", \"Single-lab interaction\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Established RASGRP3 in endothelial pathophysiology, placing it in an endothelin-1-Ras/MEK/ERK axis required for migration and for diabetes-induced vascular defects.\",\n      \"evidence\": \"Rasgrp3 loss-of-function embryos from diabetic mothers, activated RASGRP3 overexpression in primary endothelial cells, migration and signaling assays\",\n      \"pmids\": [\"21474816\", \"15572660\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Receptor-proximal coupling of endothelin-1 to RASGRP3 not detailed\", \"Single-lab models\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Showed RASGRP3 sets an anti-inflammatory threshold via Rap1, distinguishing its Rap1 output from ERK and revealing a restraining role in innate immune signaling.\",\n      \"evidence\": \"CRISPR-Cas9 RASGRP3 knockout in RAW264.7 cells, Rap1-GTP pull-down, IL-6 measurement, in vivo colitis/arthritis models\",\n      \"pmids\": [\"25118589\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How Rap1 mechanistically dampens TLR-ERK/IL-6 not fully resolved\", \"Receptor-proximal activation of RASGRP3 by TLRs unclear\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Linked RASGRP3 to the actin machinery through Arp3, providing a mechanism for its role in glioma migration and invasion beyond GTPase exchange.\",\n      \"evidence\": \"Pull-down/MS, co-IP, immunofluorescence, Arp3 siRNA, migration/invasion assays in glioma cells\",\n      \"pmids\": [\"25682201\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether RASGRP3-Arp3 interaction is direct or scaffolded unclear\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Identified RASGRP3 as the essential node coupling oncogenic GNAQ/GNA11 to Ras-MAPK in uveal melanoma, integrating both PKC-dependent and DAG-dependent activation modes.\",\n      \"evidence\": \"siRNA/shRNA knockdown, PKC inhibition, Ras-GTP pull-down in UM cell lines, GNA11Q209L mouse model, transcriptome and xenograft analyses\",\n      \"pmids\": [\"28486107\", \"29490280\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of GNAQ/11-driven RASGRP3 overexpression not fully defined\", \"Therapeutic exploitability of dual activation modes not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Demonstrated that the RASGRP3 C1 domain is pharmacologically targetable with selectivity over PKC, establishing a chemical-biology entry point.\",\n      \"evidence\": \"In vitro C1-domain competitive binding assay and cell-based Ras-GTP/PKC-delta phosphorylation selectivity with DAG-lactone compound 96\",\n      \"pmids\": [\"29860841\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vivo efficacy and pharmacology of the ligand untested\", \"Single-lab in vitro selectivity data\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Revealed post-translational control of RASGRP3 abundance, showing ubiquitin-dependent degradation modulated by the E3 ligase MID1 governs RASGRP3 stability in NPM1-mutant AML.\",\n      \"evidence\": \"Co-IP, cycloheximide chase, proliferation assays in NPM1-mutated AML cells\",\n      \"pmids\": [\"36826998\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct ubiquitination of RASGRP3 by MID1 not demonstrated\", \"Single-lab finding\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Reinforced the anti-inflammatory Rap1B output in vascular disease and identified a second E3-ligase-family regulator (UHRF1) controlling RASGRP3 protein turnover.\",\n      \"evidence\": \"Endothelial overexpression, Rap1 activity and NF-kappaB assays, endothelial-specific ApoE-/- transgenic mice, co-IP and ubiquitination assay\",\n      \"pmids\": [\"41689678\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether UHRF1 directly ubiquitinates RASGRP3 not fully established\", \"Single-lab recent finding\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the multiple activation inputs (DAG recruitment, Thr133/Ser PKC phosphorylation, c-Src tyrosine phosphorylation) and degradation pathways are integrated to bias RASGRP3 toward Ras versus Rap1 outputs in a given cell type remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model integrating C1, GEF and regulatory phosphosites\", \"No unified quantitative model of Ras-vs-Rap1 output selection\", \"Mechanism directing substrate choice across cell types unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [1, 9]},\n      {\"term_id\": \"GO:0060089\", \"supporting_discovery_ids\": [0, 16]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 2, 9]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 16]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [8, 14]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [16, 17]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"DLC1\", \"Arp3\", \"PRKCD\", \"PRKCQ\", \"SRC\", \"MID1\", \"UHRF1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":6,"faith_total":6,"faith_pct":100.0}}