Figure 2.
Inhibition of phagocytosis by YopE, YopH, and YopT. (A) Phagocytosis of an invading bacterium by a macrophage. The process involves phosphorylation of focal adhesion proteins (p130cas, Fak, Fyn, paxillin) and actin polymerization controlled by GTPases such as RhoA and Rac. Phagocytosis is followed by killing of the bacterium. (B) Resistance to phagocytosis by Yersinia. On contact, Yersinia injects Yop effectors. YopH dephosphorylates proteins from the focal adhesion (PTPase, phosphotyrosine phosphatase); YopE inactivates Rac and cdc42 by stimulating their GTPase activity (GAP, GTPase-activating protein); YopT deactivates RhoA.