ArfGap with Rho-Gap domain, ANK repeat and PH domain-containing protein 1
The ARAP subfamily includes three members, ARAP1-3, and belongs to the ADP-ribosylation factor GTPase-activating proteins (Arf GAPs) family of proteins that promotes the hydrolysis of GTP bound to Arf, thereby inactivating Arf signaling. The function of Arfs is dependent on GAPs and guanine nucleotide exchange factors (GEFs), which allow Arfs to cycle between the GDP-bound and GTP-bound forms. In addition to the Arf GAP domain, ARAPs contain the SAM (sterile-alpha motif) domain, 5 pleckstrin homology (PH) domains, the Rho-GAP domain, the Ras-association domain, and ANK repeats. ARAPs show phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3)-dependent GAP activity toward Arf6. ARAPs play important roles in endocytic trafficking, cytoskeleton reorganization in response to growth factors stimulation, and focal adhesion dynamics. ARAP1 localizes to the plasma membrane, the Golgi complex, and endosomal compartments. It displays PI(3,4,5)P3-dependent ArfGAP activity that regulates Arf-, RhoA-, and Cdc42-dependent cellular events. For example, ARAP1 inhibits the trafficking of epidermal growth factor receptor (EGFR) to the early endosome.