FIG. 10.

Model for the role of surface-localized LcrV in Yop targeting. The Ysc creates a secretion channel through the bacterial inner membrane (IM), across the periplasm (PP), and through the outer membrane (OM). These pores remain blocked in the absence of direct contact with the eukaryotic cell plasma membrane (PM) by LcrE, TyeA, and LcrG. LcrV is associated with the extracellular surface of these closed pores directly or through an additional protein (X). Upon cell contact, LcrE, TyeA, and LcrG are displaced, and LcrV mediates formation of a delivery apparatus for the transfer of Yops directly from the bacteria to the eukaryotic cell cytoplasm.