title: AGAP1, an endosome-associated, phosphoinositide-dependent ADP-ribosylation factor GTPase-activating protein that affects actin cytoskeleton.
abstract: We have identified three members of the AGAP subfamily of ASAP family ADP-ribosylation factor GTPase-activating proteins (Arf GAPs). In addition to the Arf GAP domain, these proteins contain GTP-binding protein-like, ankyrin repeat and pleckstrin homology domains. Here, we have characterized the ubiquitously expressed AGAP1/KIAA1099. AGAP1 had Arf GAP activity toward Arf1>Arf5>Arf6. Phosphatidylinositol 4,5-bisphosphate and phosphatidic acid synergistically stimulated GAP activity. As found for other ASAP family Arf GAPs, the pleckstrin homology domain was necessary for activity. Deletion of the GTP-binding protein-like domain affected lipid dependence of Arf GAP activity. In vivo effects of AGAP1 were distinct from other ASAP family Arf GAPs. Overexpressed AGAP1 induced the formation of and was associated with punctate structures containing the endocytic markers transferrin and Rab4. AP1 was redistributed from the trans-Golgi to the punctate structures. Like other ASAP family members, AGAP1 overexpression inhibited the formation of PDGF-induced ruffles. However, distinct from other ASAP family members, AGAP1 also induced the loss of actin stress fibers. Thus, AGAP1 is a phosphoinositide-dependent Arf GAP that impacts both the endocytic compartment and actin.
authors.affiliation: Laboratories of Cellular Oncology and Biochemistry, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Zhongzhen
authors.initials: Z
authors.lastname: Nie
authors.forename: Katherine T
authors.initials: KT
authors.lastname: Stanley
authors.forename: Stacey
authors.initials: S
authors.lastname: Stauffer
authors.forename: Kerry M
authors.initials: KM
authors.lastname: Jacques
authors.forename: Dianne S
authors.initials: DS
authors.lastname: Hirsch
authors.forename: Jiro
authors.initials: J
authors.lastname: Takei
authors.forename: Paul A
authors.initials: PA
authors.lastname: Randazzo
mesh_terms: D020727:ADP-Ribosylation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism*; D017931:DNA Primers; D018076:DNA, Complementary; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010716:Phosphatidylinositols / Q000378:metabolism*; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: C470574:AGAP1 protein, human; D000199:Actins; D017931:DNA Primers; D018076:DNA, Complementary; D020690:GTPase-Activating Proteins; D010716:Phosphatidylinositols; D012333:RNA, Messenger; D020727:ADP-Ribosylation Factors