title: Sorting of Golgi resident proteins into different subpopulations of COPI vesicles: a role for ArfGAP1.
abstract: We present evidence for two subpopulations of coatomer protein I vesicles, both containing high amounts of Golgi resident proteins but only minor amounts of anterograde cargo. Early Golgi proteins p24alpha2, beta1, delta1, and gamma3 are shown to be sorted together into vesicles that are distinct from those containing mannosidase II, a glycosidase of the medial Golgi stack, and GS28, a SNARE protein of the Golgi stack. Sorting into each vesicle population is Arf-1 and GTP hydrolysis dependent and is inhibited by aluminum and beryllium fluoride. Using synthetic peptides, we find that the cytoplasmic domain of p24beta1 can bind Arf GTPase-activating protein (GAP)1 and cause direct inhibition of ArfGAP1-mediated GTP hydrolysis on Arf-1 bound to liposomes and Golgi membranes. We propose a two-stage reaction to explain how GTP hydrolysis constitutes a prerequisite for sorting of resident proteins, yet becomes inhibited in their presence.
authors.affiliation: Cell Biology and Biophysics Programme, European Molecular Biology Laboratory, D-69017 Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Lanoix
authors.forename: J
authors.initials: J
authors.lastname: Ouwendijk
authors.forename: A
authors.initials: A
authors.lastname: Stark
authors.forename: E
authors.initials: E
authors.lastname: Szafer
authors.forename: D
authors.initials: D
authors.lastname: Cassel
authors.forename: K
authors.initials: K
authors.lastname: Dejgaard
authors.forename: M
authors.initials: M
authors.lastname: Weiss
authors.forename: T
authors.initials: T
authors.lastname: Nilsson
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000378:metabolism; D020727:ADP-Ribosylation Factors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D022181:COP-Coated Vesicles / Q000145:classification / Q000378:metabolism*; D002352:Carrier Proteins; D005110:Extracellular Space / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D006868:Hydrolysis; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D050766:Qb-SNARE Proteins; D051381:Rats; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D013729:Terpenes / Q000378:metabolism; D033921:Vesicular Transport Proteins
chemical_list: C503239:Arfgap1 protein, rat; D002352:Carrier Proteins; D020690:GTPase-Activating Proteins; C099509:Gosr1 protein, rat; D008565:Membrane Proteins; D010455:Peptides; D050766:Qb-SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D013729:Terpenes; D033921:Vesicular Transport Proteins; C089206:ent-13-epi-12-acetoxymanoyl oxide; D000255:Adenosine Triphosphate; D020823:ADP-Ribosylation Factor 1; D020727:ADP-Ribosylation Factors