Oligomerization of Clostridium perfringens epsilon toxin is dependent upon caveolins 1 and 2

• Published in: PloS one Vol. 7; no. 10; p. e46866
• Main Authors: Fennessey, Christine M, Sheng, Jinsong, Rubin, Donald H, McClain, Mark S
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 02.10.2012; Public Library of Science (PLoS)
• Subjects: Animals; Apoptosis; Bacterial Toxins - chemistry; Bacterial Toxins - toxicity; Biochemistry; Biology; Caveolin; Caveolin 1 - deficiency; Caveolin 1 - genetics; Caveolin 1 - metabolism; Caveolin 2 - deficiency; Caveolin 2 - genetics; Caveolin 2 - metabolism; Caveolin-1; Cell death; Cell Survival - drug effects; Cholesterol; Clostridium perfringens; Cytotoxicity; Dogs; Gene Knockdown Techniques; Genes; Glycoproteins; Homeostasis; Humans; Immunoprecipitation; Infectious diseases; Kinases; Lipids; Madin Darby Canine Kidney Cells; Medicine; Mutagenesis; Oligomerization; Oligomers; Pore formation; Protein Multimerization; Protein Structure, Quaternary; Proteins; RNA, Small Interfering - genetics; Signal transduction; Sterols; Studies; Toxicity; Toxins; United States > US; Tennessee; Nashville Tennessee
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0046866

Evidence from multiple studies suggests that Clostridium perfringens ε-toxin is a pore-forming toxin, assembling into oligomeric complexes in the plasma membrane of sensitive cells. In a previous study, we used gene-trap mutagenesis to identify mammalian factors contributing to toxin activity, including caveolin-2 (CAV2). In this study, we demonstrate the importance of caveolin-2 and its interaction partner, caveolin-1 (CAV1), in ε-toxin-induced cytotoxicity. Using CAV2-specific shRNA in a toxin-sensitive human kidney cell line, ACHN, we confirmed that cells deficient in CAV2 exhibit increased resistance to ε-toxin. Similarly, using CAV1-specific shRNA, we demonstrate that cells deficient in CAV1 also exhibit increased resistance to the toxin. Immunoprecipitation of CAV1 and CAV2 from ε-toxin-treated ACHN cells demonstrated interaction of both CAV1 and -2 with the toxin. Furthermore, blue-native PAGE indicated that the toxin and caveolins were components of a 670 kDa protein complex. Although ε-toxin binding was only slightly perturbed in caveolin-deficient cells, oligomerization of the toxin was dramatically reduced in both CAV1- and CAV2-deficient cells. These results indicate that CAV1 and -2 potentiate ε-toxin induced cytotoxicity by promoting toxin oligomerization - an event which is requisite for pore formation and, by extension, cell death.