ARHGEF25 encodes p63RhoGEF, a Rho guanine nucleotide exchange factor that serves as a critical mediator between Gαq/11-coupled GPCR signaling and RhoA activation 1. The gene produces multiple isoforms with distinct subcellular localizations: p63RhoGEF580 localizes to the plasma membrane while p63RhoGEF619 resides in the cytoplasm but translocates to the membrane upon Gαq activation 1. ARHGEF25 functions through a dual activation mechanism requiring both membrane recruitment and allosteric activation by Gαq for full RhoGEF activity 1. In disease contexts, ARHGEF25 shows opposing roles: it acts as a tumor suppressor in NK/T-cell lymphoma by promoting RHOA-mediated apoptosis through the GNAQ-ARHGEF25 complex 2, while elevated expression correlates with hypertension through enhanced RhoA/Rho kinase signaling 3. The protein is also targeted by miR-3189-3p in glioblastoma, where its downregulation contributes to tumor progression 4. Clinical significance includes its role as a biomarker in hypertensive patients, where p63RhoGEF levels correlate with blood pressure parameters 3, and its regulation by RGS2 proteins that modulate the dynamics of Gαq-p63RhoGEF interactions 5.