THE ARF1 GTPASE-ACTIVATING PROTEIN - ZINC-FINGER MOTIF AND GOLGI-COMPLEX LOCALIZATION

Hydrolysis of guanosine triphosphate (GTP) by the small guanosine trip hosphatase (GTPase) adenosine diphosphate ribosylation factor-1 (ARF1) depends on a GTPase-activating protein (GAP). A complementary DNA enc oding the ARF1 GAP was cloned from rat liver and predicts a protein wi th a zinc finger motif near the amino terminus. The GAP function requi red an intact zinc finger and additional amino-terminal residues. The ARF1 GAP was localized to the Golgi complex and was redistributed into a cytosolic pattern when cells were treated with brefeldin A, a drug that prevents ARF1-dependent association of coat proteins with the Gol gi. Thus, the GAP is likely to be recruited to the Golgi by an ARF1-de pendent mechanism.