title: Characterization of Cop I coat proteins in plant cells.
abstract: Membrane traffic in eukaryotic cells is mediated by COP (coat protein)-coated vesicles. Their existence in plant cells has not yet been unequivocally demonstrated, although coated vesicles (probably with a COP coat) can be seen by electron microscopy. At the gene level, plant cells seem to contain all the components necessary to form COP-coated vesicles. In this paper, we have used antibodies raised against mammalian COPI coat proteins to detect putative homologues in rice (Oryza sativa) cells. Using these antibodies, we have found that rice cells contain alpha-, beta-, beta'-, and gamma-COP, as well as ADP-ribosylation factor (ARF) 1 protein. In addition, we show that antibodies against mammalian beta'-COP can immunoprecipitate not only beta'-COP but also alpha-, beta-, and gamma-COP, suggesting that COPI components in rice cells exist as a complex (or coatomer) in the cytosol, as in mammalian cells. Finally, we show that COP binding to membranes is GTP-dependent, and that ARF1 also binds to membranes in a GTP-dependent manner.
authors.affiliation: Departament de Bioquímica i Biología Molecular Facultat de Farmacia, Universitat de Valencia, Burjassot (Valencia), 46100, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Contreras
authors.forename: E
authors.initials: E
authors.lastname: Ortiz-Zapater
authors.forename: L M
authors.initials: LM
authors.lastname: Castilho
authors.forename: F
authors.initials: F
authors.lastname: Aniento
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D020756:Coatomer Protein / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism*; D003429:Cross Reactions / Q000276:immunology; D003600:Cytosol / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000494:pharmacology; D008099:Liver / Q000737:chemistry / Q000166:cytology; D008861:Microsomes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D008970:Molecular Weight; D009355:Neomycin / Q000494:pharmacology; D012275:Oryza / Q000737:chemistry* / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding / Q000187:drug effects; D051381:Rats
chemical_list: D000906:Antibodies; D020756:Coatomer Protein; D006160:Guanosine Triphosphate; D020823:ADP-Ribosylation Factor 1; D009355:Neomycin