title: Copurification of rho protein and the rho-GDP dissociation inhibitor from bovine neutrophil cytosol. Effect of phosphoinositides on rho ADP-ribosylation by the C3 exoenzyme of Clostridium botulinum.
abstract: The substrate of the C3 exoenzyme from botulinum toxin is a protein which is particularly abundant in the cytosol of neutrophils [Stasia, M. J., Jouan, A., Bourmeyster, N., Boquet, P., & Vignais, P. V. (1991) Biochem. Biophys. Res. Commun. 180, 615-622]. Optimal conditions for the ADP-ribosylation of the C3 substrate have been established in order to follow the course of its purification from bovine neutrophil cytosol. In particular, phosphoinositides at micromolar concentrations were found to enhance the ADP-ribosylation capacity of the C3 substrate in crude neutrophil cytosol and partially purified fractions. A [32P]ADP-ribosylatable protein, migrating on SDS-PAGE with a mass of 24 kDa, was copurified with a 29-kDa protein by a series of chromatographic steps on DEAE-Sephacel, Biogel P60, and Mono Q. In the case of the C3 substrate, isoelectric focusing revealed two major labeled bands with pI values of 6.2 and 5.6; the pI of the 29-kDa protein was 4.8-5.0. On the basis of the amino acid sequence of peptides resolved after proteolytic digestion, the 24-kDa protein and the 29-kDa protein were identified respectively as rho and the GDP dissociation inhibitor (GDI), suggesting that rho and GDI copurify from bovine neutrophil cytosol in the form of a complex. The presence of a number of amino acid residues specific of rho A in the enzymatic digest originating from rho indicates that, among the rho proteins, at least rho A belongs to the GDI-rho complex.
authors.affiliation: Laboratoire de Biochimie, Centre d'Etudes Nucléaires, Grenoble, France.
authors.forename: N
authors.initials: N
authors.lastname: Bourmeyster
authors.forename: M J
authors.initials: MJ
authors.lastname: Stasia
authors.forename: J
authors.initials: J
authors.lastname: Garin
authors.forename: J
authors.initials: J
authors.lastname: Gagnon
authors.forename: P
authors.initials: P
authors.lastname: Boquet
authors.forename: P V
authors.initials: PV
authors.lastname: Vignais
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001905:Botulinum Toxins; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D020730:Guanine Nucleotide Dissociation Inhibitors; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009504:Neutrophils / Q000737:chemistry*; D010716:Phosphatidylinositols / Q000494:pharmacology*; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020743:rhoB GTP-Binding Protein
chemical_list: D020730:Guanine Nucleotide Dissociation Inhibitors; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D000246:Adenosine Diphosphate Ribose; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins; D020743:rhoB GTP-Binding Protein