The protein encoded by this gene is a GTPase-activating protein (GAP) which associates with the Golgi apparatus and which interacts with ADP-ribosylation factor 1 (ARF1). The encoded protein promotes hydrolysis of ARF1-bound GTP and is required for the dissociation of coat proteins from Golgi-derived membranes and vesicles. Dissociation of the coat proteins is required for the fusion of these vesicles with target compartments. The activity of this protein is stimulated by phosphoinosides and inhibited by phosphatidylcholine. Two transcript variants encoding different isoforms have been found for this gene.