title: Specific regulation of the adaptor protein complex AP-3 by the Arf GAP AGAP1.
abstract: Arf1 regulates membrane trafficking at several membrane sites by interacting with at least seven different vesicle coat proteins. Here, we test the hypothesis that Arf1-dependent coats are independently regulated by specific interaction with Arf GAPs. We find that the Arf GAP AGAP1 directly associates with and colocalizes with AP-3, a coat protein complex involved in trafficking in the endosomal-lysosomal system. Binding is mediated by the PH domain of AGAP1 and the delta and sigma3 subunits of AP-3. Overexpression of AGAP1 changes the cellular distribution of AP-3, and reduced expression of AGAP1 renders AP-3 resistant to brefeldin A. AGAP1 overexpression does not affect the distribution of other coat proteins, and AP-3 distribution is not affected by overexpression of other Arf GAPs. Cells overexpressing AGAP1 also exhibit increased LAMP1 trafficking via the plasma membrane. Taken together, these results support the hypothesis that AGAP1 directly and specifically regulates AP-3-dependent trafficking.
authors.affiliation: Laboratory of Cellular Oncology, Center for Cancer Research, National Cancer Institute, Building 37, Room 4118, Bethesda, MD 20892, USA.
authors.forename: Zhongzhen
authors.initials: Z
authors.lastname: Nie
authors.forename: Markus
authors.initials: M
authors.lastname: Boehm
authors.forename: Emily S
authors.initials: ES
authors.lastname: Boja
authors.forename: William C
authors.initials: WC
authors.lastname: Vass
authors.forename: Juan S
authors.initials: JS
authors.lastname: Bonifacino
authors.forename: Henry M
authors.initials: HM
authors.lastname: Fales
authors.forename: Paul A
authors.initials: PA
authors.lastname: Randazzo
mesh_terms: D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D020823:ADP-Ribosylation Factor 1 / Q000502:physiology*; D033963:Adaptor Protein Complex 3 / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D020126:Brefeldin A / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D020756:Coatomer Protein / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D020690:GTPase-Activating Proteins / Q000502:physiology*; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D011233:Precipitin Tests; D055503:Protein Multimerization; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D021381:Protein Transport / Q000502:physiology*; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D015003:Yeasts
chemical_list: D033963:Adaptor Protein Complex 3; D002352:Carrier Proteins; D020756:Coatomer Protein; D020690:GTPase-Activating Proteins; D011500:Protein Synthesis Inhibitors; D034741:RNA, Small Interfering; D020126:Brefeldin A; D020823:ADP-Ribosylation Factor 1