Salmonella infect cells and proliferate in intracellular vacuoles. Host cell–mediated autophagy is needed to eliminate infectious bacteria, but how autophagosomes develop on these vacuoles is incompletely understood. In Molecular Cell, Tooze and colleagues show that WIPI2b, which binds phosphatidylinositol-3-phosphate, is needed to recruit the autophagy protein Atg16L1 to the salmonella-containing vacuole. Atg16L1, in complex with Atg5 and Atg12, conjugates the marker LC3 to the lipid membrane of the developing autophagosome. Replacement of the glutamic acid residue Glu226 or Glu230 in Atg16L1 or the arginine residue Arg108 or Arg125 in WIP12b abolishes this interaction and autophagosome formation. Thus, WIP2b serves as a bridge that links the generation of phosphatidylinositol-3-phosphate on bacteria-containing vacuoles to their destruction by autophagy.

Mol. Cell 55, 238–252 (2014)