{"gene":"RASGRP4","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":2002,"finding":"RasGRP4 is a calcium/cation-dependent guanine nucleotide exchange factor (GEF) that activates H-Ras in vitro, and contains a diacylglycerol/phorbol ester-binding C1 domain. Recombinant RasGRP4 activated H-Ras in a cation-dependent manner, and transfection experiments demonstrated it functions as a DAG/phorbol ester receptor.","method":"In vitro Ras activation assay with recombinant protein; transfection with phorbol ester treatment","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro biochemical reconstitution of GEF activity plus functional transfection assays, single lab but two orthogonal methods","pmids":["11956218"],"is_preprint":false},{"year":2002,"finding":"RasGRP4 expression in the HMC-1 mast cell leukemia line (which normally expresses only non-functional splice variants) induced mast cell differentiation and granule maturation, demonstrating a required role for RasGRP4 in the final stages of mast cell development.","method":"Stable transfection of functional RasGRP4 into HMC-1 cells; morphological and histochemical analysis of differentiation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean gain-of-function in a defined cellular context with specific differentiation phenotype, single lab","pmids":["11956218"],"is_preprint":false},{"year":2002,"finding":"RasGRP4 is a Ras-specific GEF that activates Ras in myeloid cells. Expression of RasGRP4 in 32D myeloid cells elevated activated Ras-GTP levels, and PMA treatment further enhanced Ras activation and induced membrane localization of RasGRP4. RasGRP4-expressing 32D cells proliferated in a cytokine-independent manner in the presence of PMA.","method":"Ras activation assays (GST-RBD pulldown) in 32D myeloid cells expressing RasGRP4; immunofluorescence for membrane localization; cytokine-independent proliferation assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — biochemical Ras activation assay, membrane localization by imaging, and functional proliferation assay in same study, single lab with multiple orthogonal methods","pmids":["11880369"],"is_preprint":false},{"year":2002,"finding":"RasGRP4 controls the expression of hematopoietic PGD2 synthase and prostaglandin D2 production in mast cells. GeneChip analysis revealed >100-fold higher PGD2 synthase mRNA in RasGRP4+ vs. RasGRP4- HMC-1 cells, and siRNA knockdown of RasGRP4 in RBL-2H3 cells reduced PGD2 synthase protein levels.","method":"GeneChip microarray; immunoblot; calcium ionophore stimulation with PGD2 measurement; siRNA knockdown in RBL-2H3 cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (microarray, immunoblot, siRNA loss-of-function, functional PGD2 measurement) in single lab","pmids":["12493770"],"is_preprint":false},{"year":2005,"finding":"RasGRP4 acts downstream of the tyrosine kinase receptor c-Kit/CD117 and upstream of the transcription factor MITF, placing it in a defined signaling pathway controlling mast cell protease and eicosanoid mediator expression.","method":"Genetic/molecular pathway analysis using RasGRP4 isoform expression in mast cell lines and strain-dependent (C3H/HeJ) defective isoform production","journal":"Novartis Foundation symposium","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pathway position inferred from expression analysis and isoform studies, no direct epistasis experiment described in abstract","pmids":["16605128"],"is_preprint":false},{"year":2008,"finding":"The N-terminal domain of Galectin-3 (Gal-3) physically interacts with RasGRP4 and inhibits RasGRP4-mediated GTP loading on N-Ras and H-Ras. This interaction provides a mechanism by which Gal-3 reduces N-Ras-GTP levels in cancer cells.","method":"Co-immunoprecipitation/interaction assay; Ras-GTP pulldown assays following Gal-3 shRNA knockdown or PMA activation of RasGRPs; ectopic expression of Gal-3 N-terminal domain","journal":"Biochimica et biophysica acta","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — protein interaction identified with functional consequence on Ras-GTP loading, multiple cell lines tested, single lab","pmids":["18413234"],"is_preprint":false},{"year":2009,"finding":"RasGRP4 functions as a class I (Ras-activating) mutation in leukemogenesis; transplantation of RasGRP4-transduced primary bone marrow cells into mice caused T cell leukemia and myeloid leukemia. RasGRP4 cooperated with AML1 mutation (S291fsX300) to accelerate T cell leukemia onset.","method":"Mouse bone marrow transplantation model; retroviral transduction of RasGRP4 ± AML1 mutant; disease monitoring and histopathology","journal":"International journal of hematology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo bone marrow transplantation with defined genetic perturbation and clear leukemic phenotype, single lab","pmids":["19350351"],"is_preprint":false},{"year":2012,"finding":"In neutrophils, GPCR stimulation activates Ras via a PLCβ2/β3 → diacylglycerol → RasGRP4 pathway. Genetic loss of RasGRP4 phenocopies knock-in of a Ras-insensitive PI3Kγ in impairing PIP3 accumulation, PKB activation, chemokinesis, and ROS formation, establishing RasGRP4 as the RasGEF linking GPCRs to PI3Kγ activation.","method":"RasGRP4 knockout mice; PI3Kγ Ras-insensitive knock-in mice; genetic epistasis; PIP3 measurement, PKB phosphorylation assay, chemokinesis assay, ROS assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with knockout mice, phenocopied by orthogonal knock-in mutation, multiple functional readouts, replicated across assays","pmids":["22728827"],"is_preprint":false},{"year":2012,"finding":"RasGRP4-null mast cells show reduced expression of pro-inflammatory cytokines IL-1β and TNF-α following PMA stimulation. RasGRP4-null mice are protected from dextran sodium sulfate-induced colitis and cannot be induced to develop experimental arthritis by K/BxN serum transfer.","method":"Homologous recombination RasGRP4-null mice; qRT-PCR for cytokine transcripts; DSS colitis model; K/BxN serum transfer arthritis model","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic knockout with specific molecular (cytokine) and in vivo inflammatory disease phenotypes, multiple disease models in single study","pmids":["22511759"],"is_preprint":false},{"year":2016,"finding":"RasGRP4 is expressed in CD117+ splenic dendritic cells (not only mast cells). RasGRP4-null CD117+ DCs and mast cells fail to optimally induce NK cell IFN-γ production in response to LPS, demonstrating RasGRP4 is required for these innate immune cells to act as NK cell accessory cells.","method":"RasGRP4-null mice; splenic DC isolation; NK cell co-culture with LPS-stimulated DCs/MCs; IFN-γ measurement by ELISA/flow cytometry","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout with defined cellular phenotype and NK cell functional readout, single lab","pmids":["26982501"],"is_preprint":false},{"year":2019,"finding":"In DLBCL cells, RasGRP4 knockdown decreases ERK activation and increases JNK expression, inhibits cell proliferation (by reducing mitosis and promoting apoptosis), increases oxidative stress, and suppresses tumor formation in xenograft models.","method":"RasGRP4 siRNA knockdown in SUDHL-4 cells; immunoblot for ERK/JNK; proliferation, apoptosis, and oxidative stress assays; xenograft tumor model","journal":"Cell communication and signaling : CCS","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined molecular pathway changes (ERK/JNK) and both in vitro and in vivo tumor phenotypes, single lab","pmids":["31409422"],"is_preprint":false},{"year":2024,"finding":"RasGRP4 promotes inflammatory injury in diabetic kidneys during ischemia-reperfusion by regulating M1 macrophage polarization and Th17 cell differentiation, and activating the IL-17 signaling pathway. RasGRP4-KO mice show reduced renal M1 macrophage and Th17 infiltration, and less renal dysfunction and fibrosis.","method":"RasGRP4 knockout mice; high-fat diet/STZ diabetes model; renal ischemia-reperfusion injury; in vitro high glucose/hypoxia-reoxygenation; flow cytometry for macrophage/T cell phenotypes; IL-17 pathway immunoblot","journal":"JCI insight","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with defined cellular and molecular pathway phenotypes in vivo and in vitro, single lab","pmids":["39656542"],"is_preprint":false},{"year":2025,"finding":"CXCL8-CXCR2 signaling upregulates RASGRP4 expression in macrophages via PLCβ2, and RASGRP4 mediates M2 macrophage polarization through mTOR-STAT3 signaling. CXCR2 knockdown or PLCβ2 silencing reduced IL-8-induced RASGRP4 expression; RASGRP4 knockdown reduced M2 polarization markers and tumor growth in xenograft models.","method":"CXCR2 knockdown; PLCβ2 siRNA; RASGRP4 knockdown/overexpression in THP-1 cells; immunoblot for mTOR-STAT3 pathway; xenograft ovarian tumor model; flow cytometry for macrophage polarization","journal":"Apoptosis : an international journal on programmed cell death","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic perturbations with defined signaling pathway readouts, both in vitro and in vivo, single lab","pmids":["40515877"],"is_preprint":false},{"year":2025,"finding":"RasGRP4 promotes diabetic kidney fibrosis by upregulating the downstream gene Aloxe3 (arachidonate lipoxygenase 3) in macrophages. Aloxe3 enhances oxidative stress and promotes infiltration of Trem2+SPP1+ scar-associated macrophages and release of fibrotic mediators. Silencing either RasGRP4 or Aloxe3 in macrophages reduces oxidative stress and fibrosis markers.","method":"RasGRP4 knockout mice (DKD model); transcriptomic sequencing of PBMCs; colocalization of RasGRP4 and Aloxe3 in macrophages; siRNA knockdown of RasGRP4/Aloxe3 in macrophages; oxidative stress and fibrosis marker assays","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO plus downstream target identification by transcriptomics with functional validation in vitro, single lab","pmids":["40662951"],"is_preprint":false},{"year":2026,"finding":"RASGRP4 is a key co-activator of KRAS-GTP in Y1 mouse adrenocortical carcinoma cells. Mathematical modeling showed SOS alone is insufficient to explain observed KRAS-GTP levels; RASGRP4 was identified as highly expressed and accounts for the remainder of KRAS activation. CRISPR depletion of RASGRP4 reduced tumor growth and frequency in Balb/c-NUDE mice.","method":"ODE mathematical modeling; PCR panel of RasGEFs; RASGRP4 CRISPR depletion; in vivo tumor growth assay in nude mice","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPR loss-of-function with defined in vivo tumor phenotype, supported by ODE modeling, single lab","pmids":["41792200"],"is_preprint":false}],"current_model":"RASGRP4 is a calcium/cation-dependent, DAG/phorbol ester-regulated guanine nucleotide exchange factor (GEF) that activates H-Ras, N-Ras, and KRAS, acting downstream of GPCRs (via PLCβ2/β3-DAG) and c-Kit to regulate mast cell development, prostaglandin D2 synthesis, pro-inflammatory cytokine expression, neutrophil PI3Kγ-PIP3 signaling, myeloid/T cell leukemogenesis, macrophage polarization, and kidney fibrosis; its activity is negatively regulated by interaction of Galectin-3's N-terminal domain with RasGRP4."},"narrative":{"mechanistic_narrative":"RASGRP4 is a calcium/cation-dependent, diacylglycerol/phorbol-ester-regulated guanine nucleotide exchange factor (GEF) that catalyzes GTP loading on Ras GTPases to drive differentiation, inflammation, and proliferation in hematopoietic and myeloid lineages [PMID:11956218, PMID:11880369]. Biochemical reconstitution established it as a Ras-specific GEF bearing a DAG/phorbol-ester-binding C1 domain, and in myeloid cells phorbol-ester stimulation drives its membrane recruitment, elevates Ras-GTP, and supports cytokine-independent proliferation [PMID:11956218, PMID:11880369]. Upstream, RASGRP4 acts in receptor-coupled signaling cascades: in neutrophils, GPCR engagement signals through PLCβ2/β3-generated diacylglycerol to RASGRP4, which provides the Ras input that activates PI3Kγ to generate PIP3 and drive chemokinesis and ROS production [PMID:22728827], and it operates downstream of the c-Kit/CD117 receptor in mast cell mediator programs [PMID:16605128]. Through this GEF activity RASGRP4 controls late mast cell differentiation and granule maturation [PMID:11956218], hematopoietic prostaglandin D2 synthase expression and PGD2 output [PMID:12493770], and pro-inflammatory IL-1β and TNF-α expression, such that RasGRP4-null mice are protected from experimental colitis and arthritis [PMID:22511759]. Its Ras-activating activity also makes it oncogenic: RASGRP4 behaves as a class I leukemogenic lesion cooperating with AML1 mutation [PMID:19350351], sustains ERK signaling and tumor growth in DLBCL [PMID:31409422], and serves as a key co-activator of KRAS-GTP in adrenocortical carcinoma [PMID:41792200]. In macrophage biology, RASGRP4 regulates M1/M2 polarization and downstream inflammatory and fibrotic programs—via mTOR-STAT3 signaling driving M2 polarization downstream of CXCL8-CXCR2/PLCβ2 [PMID:40515877] and via an Aloxe3-dependent oxidative-stress axis promoting diabetic kidney injury and fibrosis [PMID:39656542, PMID:40662951]. RASGRP4 GEF output is negatively regulated by the N-terminal domain of Galectin-3, which binds RASGRP4 and suppresses its GTP loading of N-Ras and H-Ras [PMID:18413234].","teleology":[{"year":2002,"claim":"Established the core biochemical identity of RASGRP4 as a cation-dependent, DAG/phorbol-ester-responsive Ras GEF, defining the activity all later functions depend on.","evidence":"In vitro Ras activation with recombinant protein plus phorbol-ester transfection assays; Ras-GTP pulldowns and membrane-localization imaging in 32D myeloid cells","pmids":["11956218","11880369"],"confidence":"High","gaps":["Did not resolve which endogenous Ras isoform predominates in physiological cells","C1-domain DAG binding inferred functionally without structural characterization"]},{"year":2002,"claim":"Linked RASGRP4 GEF activity to a cellular program by showing it drives terminal mast cell differentiation and controls hematopoietic PGD2 synthase/PGD2 output.","evidence":"Gain-of-function expression in HMC-1 cells with differentiation scoring; GeneChip, immunoblot, and siRNA knockdown in RBL-2H3 cells with PGD2 measurement","pmids":["11956218","12493770"],"confidence":"High","gaps":["Transcriptional intermediaries between Ras activation and PGD2 synthase induction not mapped","Performed largely in cell lines rather than primary mast cells"]},{"year":2005,"claim":"Positioned RASGRP4 within a receptor-to-transcription axis, placing it downstream of c-Kit and upstream of MITF in mast cell mediator control.","evidence":"Pathway inference from isoform expression analysis and strain-dependent defective isoform production","pmids":["16605128"],"confidence":"Low","gaps":["No direct epistasis experiment described to order c-Kit, RASGRP4, and MITF","Conclusions drawn from expression correlation rather than perturbation"]},{"year":2008,"claim":"Identified a negative regulator of RASGRP4, showing Galectin-3's N-terminal domain physically binds RASGRP4 and dampens its Ras-GTP loading.","evidence":"Co-immunoprecipitation, Ras-GTP pulldowns after Gal-3 shRNA or PMA activation, and ectopic Gal-3 N-terminal domain expression across cancer lines","pmids":["18413234"],"confidence":"Medium","gaps":["Interaction interface on RASGRP4 not mapped","Single-lab interaction data without reciprocal structural validation"]},{"year":2009,"claim":"Demonstrated RASGRP4 is oncogenic in vivo, functioning as a class I Ras-activating lesion that causes and cooperatively accelerates leukemia.","evidence":"Mouse bone marrow transplantation with retroviral RASGRP4 ± AML1 mutant, with disease monitoring and histopathology","pmids":["19350351"],"confidence":"Medium","gaps":["Did not define the Ras isoform or downstream effectors driving transformation","Overexpression-based model may not reflect endogenous regulation"]},{"year":2012,"claim":"Defined the physiological GPCR-to-PI3Kγ signaling role of RASGRP4 in neutrophils through genetic epistasis, establishing it as the GEF linking DAG to Ras-dependent PI3Kγ activation.","evidence":"RasGRP4-knockout and Ras-insensitive PI3Kγ knock-in mice with PIP3, PKB phosphorylation, chemokinesis, and ROS readouts","pmids":["22728827"],"confidence":"High","gaps":["Direct biochemical demonstration of RASGRP4-PI3Kγ Ras handoff not isolated from cellular context","Which Ras isoform couples to PI3Kγ in neutrophils unresolved"]},{"year":2012,"claim":"Showed RASGRP4 drives pro-inflammatory cytokine expression and is required for inflammatory disease in vivo, linking its signaling to colitis and arthritis pathology.","evidence":"RasGRP4-null mice with qRT-PCR for IL-1β/TNF-α and DSS colitis and K/BxN serum-transfer arthritis models","pmids":["22511759"],"confidence":"High","gaps":["Cell-type-specific contribution to disease not dissected","Transcriptional mechanism connecting RASGRP4 to cytokine induction unmapped"]},{"year":2016,"claim":"Extended RASGRP4 function beyond mast cells, showing it is needed in CD117+ dendritic cells and mast cells for them to act as NK cell accessory cells.","evidence":"RasGRP4-null mice, splenic DC isolation, and DC/MC-NK co-culture with LPS and IFN-γ readout","pmids":["26982501"],"confidence":"Medium","gaps":["Molecular signal from RASGRP4 to NK-activating output not defined","Single-lab functional study"]},{"year":2019,"claim":"Implicated RASGRP4 in solid-tumor/lymphoma signaling balance, showing it sustains ERK activation and proliferation while restraining JNK and oxidative stress in DLBCL.","evidence":"siRNA knockdown in SUDHL-4 cells with ERK/JNK immunoblot, proliferation/apoptosis/oxidative-stress assays, and xenografts","pmids":["31409422"],"confidence":"Medium","gaps":["Mechanism by which RASGRP4 suppresses JNK not established","Knockdown-only loss-of-function in a single line"]},{"year":2024,"claim":"Defined a role for RASGRP4 in macrophage and T-cell-driven kidney inflammation, linking it to M1 polarization, Th17 differentiation, and IL-17 signaling.","evidence":"RasGRP4-knockout mice in diabetes/ischemia-reperfusion injury models with flow cytometry and IL-17 pathway immunoblot","pmids":["39656542"],"confidence":"Medium","gaps":["Direct GEF substrate connecting RASGRP4 to IL-17 signaling not shown","Macrophage versus T-cell contributions not separated genetically"]},{"year":2025,"claim":"Resolved upstream and downstream macrophage circuitry, placing RASGRP4 in a CXCL8-CXCR2/PLCβ2 input driving M2 polarization via mTOR-STAT3 and a downstream Aloxe3 oxidative-stress/fibrosis axis.","evidence":"CXCR2 and PLCβ2 silencing, RASGRP4 knockdown/overexpression in THP-1 cells, mTOR-STAT3 immunoblot, xenografts; RasGRP4-KO DKD mice with transcriptomics and Aloxe3 colocalization/knockdown","pmids":["40515877","40662951"],"confidence":"Medium","gaps":["How RASGRP4 GEF output engages mTOR-STAT3 versus Aloxe3 transcriptionally is not mechanistically bridged","Both axes characterized in single labs without reciprocal validation"]},{"year":2026,"claim":"Quantitatively established RASGRP4 as a major co-activator of KRAS-GTP in carcinoma, accounting for activation that SOS alone cannot explain.","evidence":"ODE mathematical modeling, RasGEF expression panel, CRISPR depletion of RASGRP4, and tumor growth assays in nude mice","pmids":["41792200"],"confidence":"Medium","gaps":["Direct biochemical KRAS exchange by RASGRP4 not reconstituted in this system","Modeling-derived conclusion in a single cell line"]},{"year":null,"claim":"It remains unresolved how RASGRP4 selectively engages different Ras isoforms and effector branches (PI3Kγ, ERK, mTOR-STAT3, IL-17) across cell types, and how its DAG/cation regulation and Galectin-3 inhibition are integrated structurally.","evidence":"No structural or reconstituted mechanistic study addressing isoform/effector selectivity in the timeline","pmids":[],"confidence":"Low","gaps":["No structure of RASGRP4 or its Ras/DAG/Galectin-3 complexes","No unified model linking GEF activity to the divergent downstream effectors observed in different tissues"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,2,5]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,2,7]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,7]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[8,9,11]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[6,10,14]}],"complexes":[],"partners":["LGALS3","HRAS","NRAS","KRAS","PIK3CG"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q8TDF6","full_name":"RAS guanyl-releasing protein 4","aliases":[],"length_aa":673,"mass_kda":74.9,"function":"Functions as a cation- and diacylglycerol (DAG)-regulated nucleotide exchange factor activating Ras through the exchange of bound GDP for GTP (PubMed:11880369, PubMed:11956218, PubMed:12493770, PubMed:18024961). In neutrophils, participates in a phospholipase C-activating N-formyl peptide-activated GPCR (G protein-coupled receptor) signaling pathway by promoting Ras-mediated activation of PIK3CG/PI3Kgamma to promote neutrophil functional responses (By similarity). In CD117(+) dendritic cells and mast cells, participates in an lipopolysaccharide (LPS)-activated signaling pathway that stimulates the production of interferon-gamma and other pro-inflammatory cytokines by natural killer (NK) cells (By similarity). May function in mast cell differentiation (PubMed:11880369, PubMed:11956218, PubMed:12493770, PubMed:18024961). Does not appear to be required for the development of B-cells, DC-cells, T-cells, or NK-cells (By similarity)","subcellular_location":"Cytoplasm; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q8TDF6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/RASGRP4","classification":"Not Classified","n_dependent_lines":4,"n_total_lines":1208,"dependency_fraction":0.0033112582781456954},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/RASGRP4","total_profiled":1310},"omim":[{"mim_id":"607320","title":"RAS GUANYL NUCLEOTIDE-RELEASING PROTEIN 4; RASGRP4","url":"https://www.omim.org/entry/607320"},{"mim_id":"603962","title":"RAS GUANYL NUCLEOTIDE-RELEASING PROTEIN 1; RASGRP1","url":"https://www.omim.org/entry/603962"},{"mim_id":"602598","title":"PROSTAGLANDIN D SYNTHASE, HEMATOPOIETIC; HPGDS","url":"https://www.omim.org/entry/602598"},{"mim_id":"600289","title":"MITOGEN-ACTIVATED PROTEIN KINASE 14; MAPK14","url":"https://www.omim.org/entry/600289"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"},{"location":"Plasma membrane","reliability":"Additional"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"bone marrow","ntpm":19.6},{"tissue":"lymphoid tissue","ntpm":9.4}],"url":"https://www.proteinatlas.org/search/RASGRP4"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q8TDF6","domains":[{"cath_id":"1.20.870.10","chopping":"38-166","consensus_level":"high","plddt":84.6383,"start":38,"end":166},{"cath_id":"1.10.840.10","chopping":"198-348_396-430","consensus_level":"high","plddt":93.0209,"start":198,"end":430},{"cath_id":"1.10.238.10","chopping":"461-536","consensus_level":"high","plddt":84.7899,"start":461,"end":536},{"cath_id":"3.30.60.20","chopping":"540-594","consensus_level":"medium","plddt":86.7782,"start":540,"end":594}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TDF6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TDF6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8TDF6-F1-predicted_aligned_error_v6.png","plddt_mean":75.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RASGRP4","jax_strain_url":"https://www.jax.org/strain/search?query=RASGRP4"},"sequence":{"accession":"Q8TDF6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8TDF6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8TDF6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8TDF6"}},"corpus_meta":[{"pmid":"11956218","id":"PMC_11956218","title":"RasGRP4, a new mast cell-restricted Ras guanine nucleotide-releasing protein with calcium- and diacylglycerol-binding motifs. Identification of defective variants of this signaling protein in asthma, mastocytosis, and mast cell leukemia patients and demonstration of the importance of RasGRP4 in mast cell development and function.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11956218","citation_count":84,"is_preprint":false},{"pmid":"11880369","id":"PMC_11880369","title":"RasGRP4 is a novel Ras activator isolated from acute myeloid leukemia.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11880369","citation_count":74,"is_preprint":false},{"pmid":"22728827","id":"PMC_22728827","title":"GPCR activation of Ras and PI3Kc in neutrophils depends on PLCb2/b3 and the RasGEF RasGRP4.","date":"2012","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/22728827","citation_count":63,"is_preprint":false},{"pmid":"12493770","id":"PMC_12493770","title":"RasGRP4 regulates the expression of prostaglandin D2 in human and rat mast cell lines.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12493770","citation_count":39,"is_preprint":false},{"pmid":"32365959","id":"PMC_32365959","title":"Whole Genome DNA Methylation Analysis of Active Pulmonary Tuberculosis Disease Identifies Novel Epigenotypes: PARP9/miR-505/RASGRP4/GNG12 Gene Methylation and Clinical Phenotypes.","date":"2020","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/32365959","citation_count":24,"is_preprint":false},{"pmid":"22511759","id":"PMC_22511759","title":"Ras guanine nucleotide-releasing protein-4 (RasGRP4) involvement in experimental arthritis and colitis.","date":"2012","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/22511759","citation_count":21,"is_preprint":false},{"pmid":"18413234","id":"PMC_18413234","title":"Galectin-3 regulates RasGRP4-mediated activation of N-Ras and H-Ras.","date":"2008","source":"Biochimica et biophysica acta","url":"https://pubmed.ncbi.nlm.nih.gov/18413234","citation_count":21,"is_preprint":false},{"pmid":"19350351","id":"PMC_19350351","title":"Possible involvement of RasGRP4 in leukemogenesis.","date":"2009","source":"International journal of hematology","url":"https://pubmed.ncbi.nlm.nih.gov/19350351","citation_count":18,"is_preprint":false},{"pmid":"31409422","id":"PMC_31409422","title":"The critical role of RasGRP4 in the growth of diffuse large B cell lymphoma.","date":"2019","source":"Cell communication and signaling : CCS","url":"https://pubmed.ncbi.nlm.nih.gov/31409422","citation_count":12,"is_preprint":false},{"pmid":"26982501","id":"PMC_26982501","title":"CD117+ Dendritic and Mast Cells Are Dependent on RasGRP4 to Function as Accessory Cells for Optimal Natural Killer Cell-Mediated Responses to Lipopolysaccharide.","date":"2016","source":"PloS 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symposium","url":"https://pubmed.ncbi.nlm.nih.gov/16605128","citation_count":4,"is_preprint":false},{"pmid":"40662951","id":"PMC_40662951","title":"RasGRP4 Exacerbates Diabetic Kidney Fibrosis via Aloxe3-Mediated Oxidative Stress and Scar-Associated Macrophage Activation.","date":"2025","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/40662951","citation_count":3,"is_preprint":false},{"pmid":"40862743","id":"PMC_40862743","title":"CircIDH2 Modulates Porcine Adipogenesis via the miR-193a-5p/RASGRP4 Axis: Implications for ceRNA-Mediated Regulation of Fat Deposition.","date":"2025","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/40862743","citation_count":0,"is_preprint":false},{"pmid":"41792200","id":"PMC_41792200","title":"RASGRP4 is a key factor in the KRAS activation mediated by SOS in tumor Y1 adrenocortical cell lines.","date":"2026","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/41792200","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.07.23.663512","title":"RASGRP4 is a key factor in KRAS activation mediated by SOS in Y1 mouse tumor cell line","date":"2025-07-26","source":"bioRxiv","url":"https://doi.org/10.1101/2025.07.23.663512","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.07.18.664368","title":"Epigenome-wide Association Study of Psilocybin-Induced Methylome Changes in Alcohol Use Disorder","date":"2025-07-18","source":"bioRxiv","url":"https://doi.org/10.1101/2025.07.18.664368","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11638,"output_tokens":4048,"usd":0.047817,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11820,"output_tokens":4420,"usd":0.0848,"stage2_stop_reason":"end_turn"},"total_usd":0.132617,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"RasGRP4 is a calcium/cation-dependent guanine nucleotide exchange factor (GEF) that activates H-Ras in vitro, and contains a diacylglycerol/phorbol ester-binding C1 domain. Recombinant RasGRP4 activated H-Ras in a cation-dependent manner, and transfection experiments demonstrated it functions as a DAG/phorbol ester receptor.\",\n      \"method\": \"In vitro Ras activation assay with recombinant protein; transfection with phorbol ester treatment\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro biochemical reconstitution of GEF activity plus functional transfection assays, single lab but two orthogonal methods\",\n      \"pmids\": [\"11956218\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"RasGRP4 expression in the HMC-1 mast cell leukemia line (which normally expresses only non-functional splice variants) induced mast cell differentiation and granule maturation, demonstrating a required role for RasGRP4 in the final stages of mast cell development.\",\n      \"method\": \"Stable transfection of functional RasGRP4 into HMC-1 cells; morphological and histochemical analysis of differentiation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean gain-of-function in a defined cellular context with specific differentiation phenotype, single lab\",\n      \"pmids\": [\"11956218\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"RasGRP4 is a Ras-specific GEF that activates Ras in myeloid cells. Expression of RasGRP4 in 32D myeloid cells elevated activated Ras-GTP levels, and PMA treatment further enhanced Ras activation and induced membrane localization of RasGRP4. RasGRP4-expressing 32D cells proliferated in a cytokine-independent manner in the presence of PMA.\",\n      \"method\": \"Ras activation assays (GST-RBD pulldown) in 32D myeloid cells expressing RasGRP4; immunofluorescence for membrane localization; cytokine-independent proliferation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — biochemical Ras activation assay, membrane localization by imaging, and functional proliferation assay in same study, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"11880369\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"RasGRP4 controls the expression of hematopoietic PGD2 synthase and prostaglandin D2 production in mast cells. GeneChip analysis revealed >100-fold higher PGD2 synthase mRNA in RasGRP4+ vs. RasGRP4- HMC-1 cells, and siRNA knockdown of RasGRP4 in RBL-2H3 cells reduced PGD2 synthase protein levels.\",\n      \"method\": \"GeneChip microarray; immunoblot; calcium ionophore stimulation with PGD2 measurement; siRNA knockdown in RBL-2H3 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (microarray, immunoblot, siRNA loss-of-function, functional PGD2 measurement) in single lab\",\n      \"pmids\": [\"12493770\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"RasGRP4 acts downstream of the tyrosine kinase receptor c-Kit/CD117 and upstream of the transcription factor MITF, placing it in a defined signaling pathway controlling mast cell protease and eicosanoid mediator expression.\",\n      \"method\": \"Genetic/molecular pathway analysis using RasGRP4 isoform expression in mast cell lines and strain-dependent (C3H/HeJ) defective isoform production\",\n      \"journal\": \"Novartis Foundation symposium\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pathway position inferred from expression analysis and isoform studies, no direct epistasis experiment described in abstract\",\n      \"pmids\": [\"16605128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"The N-terminal domain of Galectin-3 (Gal-3) physically interacts with RasGRP4 and inhibits RasGRP4-mediated GTP loading on N-Ras and H-Ras. This interaction provides a mechanism by which Gal-3 reduces N-Ras-GTP levels in cancer cells.\",\n      \"method\": \"Co-immunoprecipitation/interaction assay; Ras-GTP pulldown assays following Gal-3 shRNA knockdown or PMA activation of RasGRPs; ectopic expression of Gal-3 N-terminal domain\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — protein interaction identified with functional consequence on Ras-GTP loading, multiple cell lines tested, single lab\",\n      \"pmids\": [\"18413234\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"RasGRP4 functions as a class I (Ras-activating) mutation in leukemogenesis; transplantation of RasGRP4-transduced primary bone marrow cells into mice caused T cell leukemia and myeloid leukemia. RasGRP4 cooperated with AML1 mutation (S291fsX300) to accelerate T cell leukemia onset.\",\n      \"method\": \"Mouse bone marrow transplantation model; retroviral transduction of RasGRP4 ± AML1 mutant; disease monitoring and histopathology\",\n      \"journal\": \"International journal of hematology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo bone marrow transplantation with defined genetic perturbation and clear leukemic phenotype, single lab\",\n      \"pmids\": [\"19350351\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"In neutrophils, GPCR stimulation activates Ras via a PLCβ2/β3 → diacylglycerol → RasGRP4 pathway. Genetic loss of RasGRP4 phenocopies knock-in of a Ras-insensitive PI3Kγ in impairing PIP3 accumulation, PKB activation, chemokinesis, and ROS formation, establishing RasGRP4 as the RasGEF linking GPCRs to PI3Kγ activation.\",\n      \"method\": \"RasGRP4 knockout mice; PI3Kγ Ras-insensitive knock-in mice; genetic epistasis; PIP3 measurement, PKB phosphorylation assay, chemokinesis assay, ROS assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with knockout mice, phenocopied by orthogonal knock-in mutation, multiple functional readouts, replicated across assays\",\n      \"pmids\": [\"22728827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"RasGRP4-null mast cells show reduced expression of pro-inflammatory cytokines IL-1β and TNF-α following PMA stimulation. RasGRP4-null mice are protected from dextran sodium sulfate-induced colitis and cannot be induced to develop experimental arthritis by K/BxN serum transfer.\",\n      \"method\": \"Homologous recombination RasGRP4-null mice; qRT-PCR for cytokine transcripts; DSS colitis model; K/BxN serum transfer arthritis model\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic knockout with specific molecular (cytokine) and in vivo inflammatory disease phenotypes, multiple disease models in single study\",\n      \"pmids\": [\"22511759\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RasGRP4 is expressed in CD117+ splenic dendritic cells (not only mast cells). RasGRP4-null CD117+ DCs and mast cells fail to optimally induce NK cell IFN-γ production in response to LPS, demonstrating RasGRP4 is required for these innate immune cells to act as NK cell accessory cells.\",\n      \"method\": \"RasGRP4-null mice; splenic DC isolation; NK cell co-culture with LPS-stimulated DCs/MCs; IFN-γ measurement by ELISA/flow cytometry\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout with defined cellular phenotype and NK cell functional readout, single lab\",\n      \"pmids\": [\"26982501\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In DLBCL cells, RasGRP4 knockdown decreases ERK activation and increases JNK expression, inhibits cell proliferation (by reducing mitosis and promoting apoptosis), increases oxidative stress, and suppresses tumor formation in xenograft models.\",\n      \"method\": \"RasGRP4 siRNA knockdown in SUDHL-4 cells; immunoblot for ERK/JNK; proliferation, apoptosis, and oxidative stress assays; xenograft tumor model\",\n      \"journal\": \"Cell communication and signaling : CCS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined molecular pathway changes (ERK/JNK) and both in vitro and in vivo tumor phenotypes, single lab\",\n      \"pmids\": [\"31409422\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"RasGRP4 promotes inflammatory injury in diabetic kidneys during ischemia-reperfusion by regulating M1 macrophage polarization and Th17 cell differentiation, and activating the IL-17 signaling pathway. RasGRP4-KO mice show reduced renal M1 macrophage and Th17 infiltration, and less renal dysfunction and fibrosis.\",\n      \"method\": \"RasGRP4 knockout mice; high-fat diet/STZ diabetes model; renal ischemia-reperfusion injury; in vitro high glucose/hypoxia-reoxygenation; flow cytometry for macrophage/T cell phenotypes; IL-17 pathway immunoblot\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with defined cellular and molecular pathway phenotypes in vivo and in vitro, single lab\",\n      \"pmids\": [\"39656542\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CXCL8-CXCR2 signaling upregulates RASGRP4 expression in macrophages via PLCβ2, and RASGRP4 mediates M2 macrophage polarization through mTOR-STAT3 signaling. CXCR2 knockdown or PLCβ2 silencing reduced IL-8-induced RASGRP4 expression; RASGRP4 knockdown reduced M2 polarization markers and tumor growth in xenograft models.\",\n      \"method\": \"CXCR2 knockdown; PLCβ2 siRNA; RASGRP4 knockdown/overexpression in THP-1 cells; immunoblot for mTOR-STAT3 pathway; xenograft ovarian tumor model; flow cytometry for macrophage polarization\",\n      \"journal\": \"Apoptosis : an international journal on programmed cell death\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic perturbations with defined signaling pathway readouts, both in vitro and in vivo, single lab\",\n      \"pmids\": [\"40515877\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RasGRP4 promotes diabetic kidney fibrosis by upregulating the downstream gene Aloxe3 (arachidonate lipoxygenase 3) in macrophages. Aloxe3 enhances oxidative stress and promotes infiltration of Trem2+SPP1+ scar-associated macrophages and release of fibrotic mediators. Silencing either RasGRP4 or Aloxe3 in macrophages reduces oxidative stress and fibrosis markers.\",\n      \"method\": \"RasGRP4 knockout mice (DKD model); transcriptomic sequencing of PBMCs; colocalization of RasGRP4 and Aloxe3 in macrophages; siRNA knockdown of RasGRP4/Aloxe3 in macrophages; oxidative stress and fibrosis marker assays\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO plus downstream target identification by transcriptomics with functional validation in vitro, single lab\",\n      \"pmids\": [\"40662951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"RASGRP4 is a key co-activator of KRAS-GTP in Y1 mouse adrenocortical carcinoma cells. Mathematical modeling showed SOS alone is insufficient to explain observed KRAS-GTP levels; RASGRP4 was identified as highly expressed and accounts for the remainder of KRAS activation. CRISPR depletion of RASGRP4 reduced tumor growth and frequency in Balb/c-NUDE mice.\",\n      \"method\": \"ODE mathematical modeling; PCR panel of RasGEFs; RASGRP4 CRISPR depletion; in vivo tumor growth assay in nude mice\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPR loss-of-function with defined in vivo tumor phenotype, supported by ODE modeling, single lab\",\n      \"pmids\": [\"41792200\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"RASGRP4 is a calcium/cation-dependent, DAG/phorbol ester-regulated guanine nucleotide exchange factor (GEF) that activates H-Ras, N-Ras, and KRAS, acting downstream of GPCRs (via PLCβ2/β3-DAG) and c-Kit to regulate mast cell development, prostaglandin D2 synthesis, pro-inflammatory cytokine expression, neutrophil PI3Kγ-PIP3 signaling, myeloid/T cell leukemogenesis, macrophage polarization, and kidney fibrosis; its activity is negatively regulated by interaction of Galectin-3's N-terminal domain with RasGRP4.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RASGRP4 is a calcium/cation-dependent, diacylglycerol/phorbol-ester-regulated guanine nucleotide exchange factor (GEF) that catalyzes GTP loading on Ras GTPases to drive differentiation, inflammation, and proliferation in hematopoietic and myeloid lineages [#0, #2]. Biochemical reconstitution established it as a Ras-specific GEF bearing a DAG/phorbol-ester-binding C1 domain, and in myeloid cells phorbol-ester stimulation drives its membrane recruitment, elevates Ras-GTP, and supports cytokine-independent proliferation [#0, #2]. Upstream, RASGRP4 acts in receptor-coupled signaling cascades: in neutrophils, GPCR engagement signals through PLCβ2/β3-generated diacylglycerol to RASGRP4, which provides the Ras input that activates PI3Kγ to generate PIP3 and drive chemokinesis and ROS production [#7], and it operates downstream of the c-Kit/CD117 receptor in mast cell mediator programs [#4]. Through this GEF activity RASGRP4 controls late mast cell differentiation and granule maturation [#1], hematopoietic prostaglandin D2 synthase expression and PGD2 output [#3], and pro-inflammatory IL-1β and TNF-α expression, such that RasGRP4-null mice are protected from experimental colitis and arthritis [#8]. Its Ras-activating activity also makes it oncogenic: RASGRP4 behaves as a class I leukemogenic lesion cooperating with AML1 mutation [#6], sustains ERK signaling and tumor growth in DLBCL [#10], and serves as a key co-activator of KRAS-GTP in adrenocortical carcinoma [#14]. In macrophage biology, RASGRP4 regulates M1/M2 polarization and downstream inflammatory and fibrotic programs—via mTOR-STAT3 signaling driving M2 polarization downstream of CXCL8-CXCR2/PLCβ2 [#12] and via an Aloxe3-dependent oxidative-stress axis promoting diabetic kidney injury and fibrosis [#11, #13]. RASGRP4 GEF output is negatively regulated by the N-terminal domain of Galectin-3, which binds RASGRP4 and suppresses its GTP loading of N-Ras and H-Ras [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established the core biochemical identity of RASGRP4 as a cation-dependent, DAG/phorbol-ester-responsive Ras GEF, defining the activity all later functions depend on.\",\n      \"evidence\": \"In vitro Ras activation with recombinant protein plus phorbol-ester transfection assays; Ras-GTP pulldowns and membrane-localization imaging in 32D myeloid cells\",\n      \"pmids\": [\"11956218\", \"11880369\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve which endogenous Ras isoform predominates in physiological cells\", \"C1-domain DAG binding inferred functionally without structural characterization\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Linked RASGRP4 GEF activity to a cellular program by showing it drives terminal mast cell differentiation and controls hematopoietic PGD2 synthase/PGD2 output.\",\n      \"evidence\": \"Gain-of-function expression in HMC-1 cells with differentiation scoring; GeneChip, immunoblot, and siRNA knockdown in RBL-2H3 cells with PGD2 measurement\",\n      \"pmids\": [\"11956218\", \"12493770\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Transcriptional intermediaries between Ras activation and PGD2 synthase induction not mapped\", \"Performed largely in cell lines rather than primary mast cells\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Positioned RASGRP4 within a receptor-to-transcription axis, placing it downstream of c-Kit and upstream of MITF in mast cell mediator control.\",\n      \"evidence\": \"Pathway inference from isoform expression analysis and strain-dependent defective isoform production\",\n      \"pmids\": [\"16605128\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct epistasis experiment described to order c-Kit, RASGRP4, and MITF\", \"Conclusions drawn from expression correlation rather than perturbation\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Identified a negative regulator of RASGRP4, showing Galectin-3's N-terminal domain physically binds RASGRP4 and dampens its Ras-GTP loading.\",\n      \"evidence\": \"Co-immunoprecipitation, Ras-GTP pulldowns after Gal-3 shRNA or PMA activation, and ectopic Gal-3 N-terminal domain expression across cancer lines\",\n      \"pmids\": [\"18413234\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interaction interface on RASGRP4 not mapped\", \"Single-lab interaction data without reciprocal structural validation\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Demonstrated RASGRP4 is oncogenic in vivo, functioning as a class I Ras-activating lesion that causes and cooperatively accelerates leukemia.\",\n      \"evidence\": \"Mouse bone marrow transplantation with retroviral RASGRP4 ± AML1 mutant, with disease monitoring and histopathology\",\n      \"pmids\": [\"19350351\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not define the Ras isoform or downstream effectors driving transformation\", \"Overexpression-based model may not reflect endogenous regulation\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Defined the physiological GPCR-to-PI3Kγ signaling role of RASGRP4 in neutrophils through genetic epistasis, establishing it as the GEF linking DAG to Ras-dependent PI3Kγ activation.\",\n      \"evidence\": \"RasGRP4-knockout and Ras-insensitive PI3Kγ knock-in mice with PIP3, PKB phosphorylation, chemokinesis, and ROS readouts\",\n      \"pmids\": [\"22728827\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct biochemical demonstration of RASGRP4-PI3Kγ Ras handoff not isolated from cellular context\", \"Which Ras isoform couples to PI3Kγ in neutrophils unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Showed RASGRP4 drives pro-inflammatory cytokine expression and is required for inflammatory disease in vivo, linking its signaling to colitis and arthritis pathology.\",\n      \"evidence\": \"RasGRP4-null mice with qRT-PCR for IL-1β/TNF-α and DSS colitis and K/BxN serum-transfer arthritis models\",\n      \"pmids\": [\"22511759\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cell-type-specific contribution to disease not dissected\", \"Transcriptional mechanism connecting RASGRP4 to cytokine induction unmapped\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Extended RASGRP4 function beyond mast cells, showing it is needed in CD117+ dendritic cells and mast cells for them to act as NK cell accessory cells.\",\n      \"evidence\": \"RasGRP4-null mice, splenic DC isolation, and DC/MC-NK co-culture with LPS and IFN-γ readout\",\n      \"pmids\": [\"26982501\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular signal from RASGRP4 to NK-activating output not defined\", \"Single-lab functional study\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Implicated RASGRP4 in solid-tumor/lymphoma signaling balance, showing it sustains ERK activation and proliferation while restraining JNK and oxidative stress in DLBCL.\",\n      \"evidence\": \"siRNA knockdown in SUDHL-4 cells with ERK/JNK immunoblot, proliferation/apoptosis/oxidative-stress assays, and xenografts\",\n      \"pmids\": [\"31409422\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which RASGRP4 suppresses JNK not established\", \"Knockdown-only loss-of-function in a single line\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined a role for RASGRP4 in macrophage and T-cell-driven kidney inflammation, linking it to M1 polarization, Th17 differentiation, and IL-17 signaling.\",\n      \"evidence\": \"RasGRP4-knockout mice in diabetes/ischemia-reperfusion injury models with flow cytometry and IL-17 pathway immunoblot\",\n      \"pmids\": [\"39656542\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct GEF substrate connecting RASGRP4 to IL-17 signaling not shown\", \"Macrophage versus T-cell contributions not separated genetically\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Resolved upstream and downstream macrophage circuitry, placing RASGRP4 in a CXCL8-CXCR2/PLCβ2 input driving M2 polarization via mTOR-STAT3 and a downstream Aloxe3 oxidative-stress/fibrosis axis.\",\n      \"evidence\": \"CXCR2 and PLCβ2 silencing, RASGRP4 knockdown/overexpression in THP-1 cells, mTOR-STAT3 immunoblot, xenografts; RasGRP4-KO DKD mice with transcriptomics and Aloxe3 colocalization/knockdown\",\n      \"pmids\": [\"40515877\", \"40662951\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How RASGRP4 GEF output engages mTOR-STAT3 versus Aloxe3 transcriptionally is not mechanistically bridged\", \"Both axes characterized in single labs without reciprocal validation\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Quantitatively established RASGRP4 as a major co-activator of KRAS-GTP in carcinoma, accounting for activation that SOS alone cannot explain.\",\n      \"evidence\": \"ODE mathematical modeling, RasGEF expression panel, CRISPR depletion of RASGRP4, and tumor growth assays in nude mice\",\n      \"pmids\": [\"41792200\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical KRAS exchange by RASGRP4 not reconstituted in this system\", \"Modeling-derived conclusion in a single cell line\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unresolved how RASGRP4 selectively engages different Ras isoforms and effector branches (PI3Kγ, ERK, mTOR-STAT3, IL-17) across cell types, and how its DAG/cation regulation and Galectin-3 inhibition are integrated structurally.\",\n      \"evidence\": \"No structural or reconstituted mechanistic study addressing isoform/effector selectivity in the timeline\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structure of RASGRP4 or its Ras/DAG/Galectin-3 complexes\", \"No unified model linking GEF activity to the divergent downstream effectors observed in different tissues\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 2, 5]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 2, 7]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 7]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [8, 9, 11]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [6, 10, 14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"LGALS3\", \"HRAS\", \"NRAS\", \"KRAS\", \"PIK3CG\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}