The host cell chaperone Hsp90 is necessary for cytotoxic action of the binary iota-like toxins

The heat shock protein Hsp90 is essential for uptake of the binary actin ADP-ribosylating toxins Clostridium perfringens iota-toxin and Clostridium difficile transferase into eukaryotic cells. Inhibition of Hsp90 by its specific inhibitor radicicol delayed intoxication of Vero cells by these toxins. A common Hsp90-dependent mechanism for their translocation is discussed.