title: Differentiation-induced increase in Clostridium botulinum C3 exoenzyme-catalyzed ADP-ribosylation of the small GTP-binding protein Rho.
abstract: The specific [32P]ADP-ribosylation by Clostridium botulinum exoenzyme C3 was used to study differentiation-dependent changes in the regulation of the low-molecular-mass GTP-binding protein Rho. Differentiation of F9 teratocarcinoma cells to neuronal-like cells by treatment with retinoic acid and dibutyryl-adenosine 3',5'-monophosphate [(Bt)2cAMP] increased the C3-catalyzed ADP-ribosylation of RhoA proteins in cytosolic and membrane fractions by about threefold and sixfold, respectively. Phenotypical differentiation of F9 cells was not required for increase in ADP-ribosylation. Increase in ADP-ribosylation after (Bt)2cAMP and retinoic acid treatments was blocked by cycloheximide, indicating the requirement of protein biosynthesis. As deduced from specific rho mRNA amounts and from Western analysis with a monoclonal RhoA antibody, the stimulation in the [32P]ADP-ribosylation of Rho was not caused by an increased de-novo synthesis of Rho proteins. GDP increased the ADP-ribosylation of membrane-associated Rho from non-differentiated, but not from differentiated F9 cells. GTP[S] decreased ADP-ribosylation of membranous Rho from differentiated and much less from non-differentiated F9 cells. Differentiation-dependent increase in ADP-ribosylation of cytosolic Rho was reversed by protein phosphatase type-1. Treatment with SDS (0.01%) which releases Rho from complexation with guanine nucleotide dissociation inhibitor, increased ADP-ribosylation both in differentiated and non-differentiated cells, indicating no differentiation-specific change of such complexes. In total, our data indicate that the induction of the differentiation process in F9 cells is accompanied by changes in the regulation of cytosolic and membrane-associated Rho proteins.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Fritz
authors.forename: I
authors.initials: I
authors.lastname: Just
authors.forename: P
authors.initials: P
authors.lastname: Wollenberg
authors.forename: K
authors.initials: K
authors.lastname: Aktories
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism*; D000818:Animals; D001905:Botulinum Toxins; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division; D003014:Clostridium botulinum / Q000201:enzymology; D000242:Cyclic AMP / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000378:metabolism; D051381:Rats; D012266:Ribose / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D018631:ras Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D020743:rhoB GTP-Binding Protein; D000075024:rhoC GTP-Binding Protein
chemical_list: D008565:Membrane Proteins; D014212:Tretinoin; D000244:Adenosine Diphosphate; D012266:Ribose; D000242:Cyclic AMP; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins; C512911:Rhoc protein, mouse; D018631:ras Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D020743:rhoB GTP-Binding Protein; D000075024:rhoC GTP-Binding Protein