Ras GTPase activating-like 4 protein (RASAL4), also known as Ca2+ -promoted Ras inactivator (CAPRI), is a member of the GAP1 family. Members of the GAP1 family are characterized by a conserved domain structure comprising N-terminal tandem C2 domains, a highly conserved central RasGAP domain, and a C-terminal pleckstrin-homology domain that is associated with a Bruton's tyrosine kinase motif. RASAL4, like RASAL, is a cytosolic protein that undergoes a rapid translocation to the plasma membrane in response to a receptor-mediated elevation in the concentration of intracellular free Ca2+ ([Ca2+]i). However, unlike RASAL, RASAL4 does not sense oscillations in [Ca2+]i.