Bacterial protein toxins inhibiting low-molecular-mass GTP-binding proteins

Int J Med Microbiol. 2001 Sep;291(4):243-50. doi: 10.1078/1438-4221-00127.


The Rho GTPases, which belong to the Ras superfamily of low-molecular-mass GTP-binding proteins, are the preferred intracellular targets of bacterial protein toxins. The Rho GTPases RhoA/B/C, Rac1/2 and Cdc42 are the master regulators of the actin cytoskeleton. Clostridium difficile toxins A and B, the causative agents of the antibiotic-associated pseudomembranous colitis, are intracellularly acting cytotoxins which mono-glucosylate the Rho GTPases. Clostridium botulinum C3 toxin, which is not related to the clostridial neurotoxins, catalyses ADP-ribosylation of RhoA/B/C but not of other Rho GTPases. Glucosylation as well as ADP-ribosylation result in functional inactivation of Rho causing disassembly of the actin cytoskeleton.

Publication types

  • Review

MeSH terms

  • Animals
  • Bacterial Toxins / pharmacology*
  • Botulism / microbiology
  • Botulism / physiopathology
  • Cells, Cultured
  • Clostridioides difficile / metabolism
  • Clostridioides difficile / pathogenicity
  • Clostridium botulinum / metabolism
  • Clostridium botulinum / pathogenicity
  • Enterocolitis, Pseudomembranous / microbiology
  • Enterocolitis, Pseudomembranous / physiopathology
  • Humans
  • rho GTP-Binding Proteins / antagonists & inhibitors*


  • Bacterial Toxins
  • rho GTP-Binding Proteins