Understanding Type IV pilus-mediated secretion in Vibrio cholerae

Bacterial pathogens depend on the expression of virulence factors that aid host infection. A mechanistic understanding of bacterial virulence can provide insights into novel antimicrobial targets and therapies. One virulence factor is Type IV pili (T4P), long thin filaments found on bacterial surfaces with roles in adhesion, DNA uptake and exoprotein secretion. The T4P system is closely related to the Type II secretion (T2S) system where periplasmic “pseudo-pili” exhibit a piston-like motion for exoprotein export. My research aims to understand T4P-mediated exoprotein secretion in the simple T4P system of Vibrio cholerae. I show that the exoprotein’s flexible N-terminal segment is the export signal, which may bind to minor pilin at the pilus tip for delivery across the secretin channel.