Bacteria‐generated PtdIns(3)P Recruits VAMP8 to Facilitate Phagocytosis

Salmonella enterica serovar Typhimurium invades non‐phagocytic cells by inducing macropinocytosis. SopB is involved in modulating actin dynamics to promote Salmonella ‐induced invasion. We report here that SopB‐generated PtdIns(3) P binds VAMP8/endobrevin to promote efficient bacterial phagocytosis. VAMP8 is recruited to Salmonella ‐induced macropinosomes in a nocodazole‐dependent, but Brefeldin A‐independent, manner. We found that VAMP8 directly binds to and colocalizes with PtdIns(3) P . The inositol phosphatase activity of SopB is required for PtdIns(3) P and VAMP8 accumulation, while wortmannin, a specific phosphatidylinositol 3‐kinase inhibitor, has no effect. Knockdown of endogenous VAMP8 by small interfering RNA or expression of a truncated VAMP8 (1–79aa) reduces the invasion level of wild‐type Salmonella to that of the phosphatase‐deficient SopB C460S mutant. Our study demonstrates that Salmonella exploit host SNARE proteins and vesicle trafficking to promote bacterial entry.