ARHGEF1, also known as p115-RhoGEF, is a member of the Rho guanine nucleotide exchange factor (GEF) family, specifically activating the small GTPase RhoA by catalyzing the exchange of GDP for GTP. Structurally, it contains a Dbl homology (DH) domain responsible for GEF activity, a Pleckstrin homology (PH) domain that may regulate membrane association, and an RGS-like domain that interacts with the G-protein subunits Gα12/13. This protein is expressed ubiquitously, with particularly high expression in hematopoietic and lymphoid tissues, and plays a critical role in transducing signals from G protein-coupled receptors coupled to Gα12/13 to activate RhoA and its downstream effector ROCK, thereby regulating cytoskeletal dynamics, cell contraction, and migration. Notably, ARHGEF1 acts as a dual-specificity regulator, functioning as a GAP for Gα12/13 while serving as a GEF for RhoA. Its involvement in essential physiological processes, such as angiotensin II-induced vascular smooth muscle contraction, underscores its importance, while mutations in the ARHGEF1 gene are associated with immunodeficiency 62 and other potential pathologies.