title: Phosphorylation of Rho GDI stabilizes the Rho A-Rho GDI complex in neutrophil cytosol.
abstract: The GDP dissociation inhibitor Rho GDI from bovine neutrophil cytosol was purified in association with prenylated Rho A. Upon treatment of this complex with alkaline phosphatase, the Rho A and Rho GDI components were released to their free forms. Following migration in 2D-PAGE and specific immunodetection, the shape of the spot of Rho GDI was found to depend markedly on whether Rho GDI subjected to electrophoresis was present in a Rho A-Rho GDI complex or in a free form. In the first case Rho GDI focused as an elongated spot between pI 5.2 and pI 4.6 whereas in the later case it focused at a pI of 5.0-5.2 as a round spot. Activation of neutrophils by anaphylatoxin C5a in a [32Pi] supplemented medium resulted in radiolabeling of Rho GDI. In vitro incubation of Rho GDI with a neutrophil homogenate in the presence of [gamma 32P] ATP led also to radiolabeling of Rho GDI. Taken together these results suggest that Rho GDI in the Rho A-Rho GDI complex is phosphorylated and that the stability of the complex depends on the phosphorylation state of Rho GDI.
authors.affiliation: Laboratoire de Biochimie, URA 1130 CNRS, Départment de Biologie Moléculaire et Structurale, CEA/Grenoble, France.
authors.forename: N
authors.initials: N
authors.lastname: Bourmeyster
authors.forename: P V
authors.initials: PV
authors.lastname: Vignais
mesh_terms: D000469:Alkaline Phosphatase / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D003600:Cytosol / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D010766:Phosphorylation; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020742:rhoA GTP-Binding Protein
chemical_list: D020730:Guanine Nucleotide Dissociation Inhibitors; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D009243:NAD; D000469:Alkaline Phosphatase; D019204:GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein