Section 41
Chapter 40,445

Inhibition of cytochalasin D-stimulated G-actin ATPase by ADP-ribosylation with Clostridium perfringens iota toxin

Geipel, U.; Just, I.; Aktories, K.

Biochemical Journal 266(2): 335-339


ISSN/ISBN: 0264-6021
PMID: 2138453
DOI: 10.1042/bj2660335
Accession: 040444885

Clostridium perfringens iota toxin belongs to a novel family of actin-ADP-ribosylating toxins. The effects of ADP-ribosylation of skeletal muscle actin by Clostridium perfringens iota toxin on cytochalasin D-stimulated actin ATPase activity was studied. Cytochalasin D stimulated actin-catalysed ATP hydrolysis maximally by about 30-fold. ADP-ribosylation of actin completely inhibited cytochalasin D-stimulated ATP hydrolysis. Inhibition of ATPase activity occurred at actin concentrations below the critical concentration (0.1 microM), at low concentrations of Mg2+ (50 microM) and even in the actin-DNAase I complex, indicating that ADP-ribosylation of actin blocks the ATPase activity of monomeric actin and that the inhibitory effect is not due to inhibition of the polymerization of actin.

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