Entrapment of Rho ADP-ribosylated by Clostridium botulinum C3 exoenzyme in the Rho-guanine nucleotide dissociation inhibitor-1 complex.
RhoA, -B, and -C are ADP-ribosylated by Clostridium botulinum exoenzyme C3 to induce redistribution of the actin filaments in intact cells, a finding that has led to the notion that the ADP-ribosylation blocks coupling of Rho to the downstream effectors. ADP-ribosylation, however, does not alter nucleotide binding, intrinsic, and GTPase-activating protein-stimulated GTPase activity. ADP-ribosylated Rho is even capable of activating the effector protein ROK in a recombinant system. Treatment of cells with a cell-permeable chimeric C3 toxin led to complete localization of modified Rho to the cytosolic fraction based on the complexation of ADP-ribosylated Rho with the guanine-nucleotide dissociation inhibitor-1 (GDI-1). The modified complex turned out to be resistant to phosphatidylinositol 4,5-bisphosphate- and GTPgammaS-induced release of Rho from GDI-1. Thus, ADP-ribosylation leads to entrapment of Rho in the GDI-1 complex. The increased stability of the GDI complex prevented binding of Rho to membrane-associated players of the GTPase cycle such as the activating guanine nucleotide exchange factors and effector proteins.
Institut für Toxikologie, Medizinische Hochschule D-30625 Hannover, Germany. genth.harald@mh-hannover.de
Harald
H
Genth
Ralf
R
Gerhard
Akio
A
Maeda
Mutsuki
M
Amano
Kozo
K
Kaibuchi
Klaus
K
Aktories
Ingo
I
Just
D016475:3T3 Cells; D036002:ADP Ribose Transferases / Q000378:metabolism*; D000818:Animals; D001905:Botulinum Toxins / Q000378:metabolism*; D004355:Drug Stability; D004591:Electrophoresis, Polyacrylamide Gel; D020558:GTP Phosphohydrolases / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000235:genetics / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D051379:Mice; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D018631:ras Proteins; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D020743:rhoB GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D000075024:rhoC GTP-Binding Protein
C086796:GDP dissociation inhibitor 1; D020730:Guanine Nucleotide Dissociation Inhibitors; D019269:Phosphatidylinositol 4,5-Diphosphate; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D005982:Glutathione Transferase; D001905:Botulinum Toxins; D020558:GTP Phosphohydrolases; 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