Clostridium botulinum C2 toxin--new insights into the cellular up-take of the actin-ADP-ribosylating toxin.
Clostridium botulinum C2 toxin is a member of the family of binary actin-ADP-ribosylating toxins. It consists of the enzyme component C2I, and the separated binding/translocation component C2II. Proteolytically activated C2II forms heptamers and binds to a carbohydrate cell surface receptor. After attachment of C2I, the toxin complex is endocytosed to reach early endosomes. At low pH of endosomes, C2II-heptamers insert into the membrane, form pores and deliver C2I into the cytosol. Here, C2I ADP-ribosylates actin at Arg177 to block actin polymerization and to induce depolymerization of actin filaments. The mini-review describes main properties of C2 toxin and discusses new findings on the involvement of chaperones in the up-take process of the toxin.
Aktories
Klaus
K
Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany. Klaus.Aktories@pharmakol.uni-freiburg.de
Barth
Holger
H
D036002:ADP Ribose Transferases / Q000378:metabolism* / Q000494:pharmacology; D000199:Actins / Q000378:metabolism*; D001905:Botulinum Toxins / Q000378:metabolism* / Q000493:pharmacokinetics / Q000494:pharmacology; D003014:Clostridium botulinum / Q000201:enzymology / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology; D006801:Humans; D021381:Protein Transport / Q000502:physiology
D000199:Actins; D036002:ADP Ribose Transferases; D001905:Botulinum Toxins; C096324:botulinum toxin type C