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Results for “RAPGEF2”

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PubMed2026

Multi-omics and experimental validation identify RAPGEF2 as a protective prognostic biomarker in clear cell renal cell carcinoma.

Kidney Renal Clear Cell Carcinoma (KIRC) is characterized by marked molecular heterogeneity and metabolic reprogramming, underscoring the need for reliable biomarkers for prognostic assessment and individualized treatment. RAPGEF2, a guanine nucleotide exchange factor has been implicated in cell adhesion and differentiation, but its role in KIRC remains unclear. In this study, we systematically evaluated the expression pattern, prognostic significance, genomic associations, biological function, and therapeutic relevance of RAPGEF2 in KIRC through integrated multi-omics analyses and experimental validation. Pan-cancer single-cell and Spatial transcriptomic analysis revealed heterogeneous RAPGEF2 expression across tumor types, with a relatively prominent signal in KIRC, where RAPGEF2 was mainly enriched in endothelial cells. Survival analyses in the TCGA-KIRC showed that high RAPGEF2 expression was significantly associated with favorable overall survival, disease-specific survival, and progression-free interval, and these findings were validated in independent ICGC_RECA-EU and E-MTAB-1980 cohorts. Multivariate Cox regression further confirmed RAPGEF2 as an independent protective prognostic factor. Immunohistochemistry in a tissue microarray cohort demonstrated that higher RAPGEF2 protein expression was associated with improved overall survival. Genomic analyses showed that low RAPGEF2 expression was related to higher mutational burden. Functional assays demonstrated that RAPGEF2 knockdown promoted KIRC progression. Enrichment analyses indicated that RAPGEF2 may be associated with metabolic pathway remodeling, while immunotherapy cohort analyses suggested its potential association with therapeutic benefit. Collectively, RAPGEF2 is identified as a protective prognostic biomarker and potential functional regulator in KIRC.

Biomarker↗

PubMed2026

A novel G13-RAPGEF2-RAP1 signaling pathway critical for platelet adhesion and aggregation.

Hemostasis and thrombosis are strongly dependent on the unique ability of platelets to rapidly activate integrin receptors and to firmly adhere to sites of injury under shear stress conditions. Central to integrin activation is the small GTPase RAP1, which itself is activated by guanine nucleotide exchange factors (GEFs). CalDAG-GEFI (RASGRP2) is the highest expressed and functionally dominant platelet RAP-GEF. However, a genome-wide association study also suggested a significant role for RAPGEF2 (PDZ-GEFI), a low-expressed RAP-GEF, in human platelet aggregation. Here, we used mice deficient in RAPGEF2 (megakaryocyte-specific, Rapgef2mKO), CalDAG-GEFI (Caldaggef1-/-), or both RAPGEF2 and CalDAG-GEFI (DKO) to characterize the contribution of RAPGEF2 signaling to platelet function, hemostasis, and thrombosis. RAPGEF2 protein was detected in murine and human platelets. Compared with control or Caldaggef1-/- platelets, both RAP1 activation and integrin αIIbβ3-mediated aggregation were significantly diminished in DKO platelets. When compared with controls, Rapgef2mKO platelets exhibited reduced integrin activation, a more reversible aggregation response, and impaired adhesion under conditions of shear stress ex vivo and in vivo. Mechanistic studies strongly suggest that RAPGEF2 operates downstream of receptors coupled to the heterotrimeric G protein G13 (GNA13), such as αIIbβ3 and the thromboxane receptor. Together, our studies provide genetic evidence that RAPGEF2 in platelets operates downstream of G13 as an important regulator of RAP1 signaling and integrin activation, especially under conditions of elevated shear stress. These findings markedly improve our understanding of G protein signaling and integrin function in platelets, with potential implications for the development of improved platelet-targeted therapies for cardiovascular disease.

Animals↗