Figure 2.

A dynamic model for how EspF protein potentially promotes the colonization of bacteria in host cells through protein interactions. First, Tir inserts into the plasma membrane and recruits clathrin to accumulate at the point of pathogen attachment. Second, under normal circumstances, SNX9 will recruit its partner dynamin to membrane areas. Once EspF comes, it binds to SNX9 protein in competition with dynamin, and their solid interaction induces SNX9 oligomerization and increases membrane deformation activity. Third, SNX9 interacts with N-WASP, as well as with EspF, to form a complex and trigger Arp2/3-dependent polymerization of branched-chain actin filaments. Thus, we propose that their interaction facilitates the colonization of pathogenic bacteria step-by-step: membrane deformation, actin polymerization, pedestal formation, and colonization promotion.