The W(Hole) Story of β-barrel Pore-forming Toxin Vibrio cholerae Cytolysin
Bacterial β-barrel pore-forming toxins (β-PFTs) constitute a unique class of membrane-damaging cytolytic proteins.β-PFTs are, in general, produced by the pathogenic bacteria as water-soluble monomeric molecules. In contact with their target eukaryotic cells, they assemble into transmembrane oligomeric β-barrel pores, thus destroying the natural permeability barrier function of the target cell membranes. Vibrio cholerae cytolysin (VCC) is a prominent member in the β-PFT family. It is produced by most of the pathogenic strains of V. cholerae, the causal organism of the severe diarrheal disease cholera.VCC is shown to evoke critical cytotoxic effects in wide array of host eukaryotic cells, and therefore, it is considered as a potent virulence factor of V. cholerae. High-resolution three-dimensional structures are known for both the water-soluble monomeric form as well as the oligomeric pore state of VCC. However, mechanistic details of the membrane pore formation process employed by the toxin remain only partly described.One of our major research interests is focused toward elucidating the detail structure-function mechanisms associated with the b-barrel membrane pore formation process of VCC. In my talk, I will present some of our recent studies that have provided new insights regarding the mechanism of action of VCC, in the context of the generalized β-PFT mode of actions.