A 102 kDa subunit of a Golgi-associated particle has homology to beta subunits of trimeric G proteins.
We have identified a 102 kDa protein, p102, which is found on the cytoplasmic face of Golgi membranes, exocytic transport vesicles and in the cytosol. A monoclonal antibody that cross-reacts with p102 is able to immunoprecipitate a 500-600 kDa protein complex containing p102 and additional subunits. The composition of this p102-containing protein complex resembles that of the Golgi coatomer complex, which constitutes the coat of non-clathrin coated vesicles. One of the subunits of the p102 complex reacts with a monoclonal antibody that detects beta-COP, a subunit of the Golgi coatomer complex. Like beta-COP, p102 exists in a brefeldin A-sensitive association with Golgi membranes. The sequence of p102 contains an N-terminal domain composed of six repeats which are similar to those found in the beta subunit of trimeric G proteins and other regulatory proteins. We suggest that p102 may be involved in regulating membrane traffic in the constitutive exocytic pathway.
Harrison-Lavoie
K J
KJ
Institute of Cancer Research, Chester Beatty Laboratories, London, UK.
Lewis
V A
VA
Hynes
G M
GM
Collison
K S
KS
Nutland
E
E
Willison
K R
KR
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D020126:Brefeldin A; D003001:Cloning, Molecular; D020756:Coatomer Protein; D003429:Cross Reactions; D003517:Cyclopentanes / Q000494:pharmacology; D004247:DNA; D019204:GTP-Binding Proteins / Q000737:chemistry*; D006056:Golgi Apparatus / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry* / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D015293:Transducin / Q000737:chemistry
D000911:Antibodies, Monoclonal; D020756:Coatomer Protein; D003517:Cyclopentanes; D008565:Membrane Proteins; D020126:Brefeldin A; D004247:DNA; D019204:GTP-Binding Proteins; D015293:Transducin