Thiol-activated cytolysins: structure, function and role in pathogenesis

Members of the thiol-activated family of cytolysins are involved in the mec hanism of pathogenesis of a number of Gram-positive species. While they are pore-forming toxins, their major pathogenic effects may be more subtle tha n simple lysis of host cells, and may include interference with immune cell function and cytokine induction. Crystal structure, electron microscopy, m utagenesis and antibody binding studies have led to the modeling of a novel mechanism of pore formation, encompassing membrane-binding, membrane inser tion and oligomerization. Despite their designation as thiol-activated cyto lysins, it is now clear that thiol activation is not an important property of this group of toxins. (C) 2000 Federation of European Microbiological So cieties. Published by Elsevier Science B.V. All rights reserved.