Between canonical and antibacterial autophagy: Rab7 is required for GAS-containing autophagosome-like vacuole formation.

Group A streptococcus (GAS) invades nonphagocytic human cells, but here it is selectively sequestered within GAS-containing autophagosome-like vacuoles (GcAVs) and killed upon fusion of GcAvs with lysosomes. GcAV formation shares core Atg machinery with canonical starvation-induced autophagy. We have recently identified a small GTPase Rab7 as a crucial factor in GcAV formation. Since Rab7 is dispensable in canonical autophagosome formation, this represents a distinction between canonical and antibacterial autophagy at the molecular level. We also showed that homotypic fusion of the initial GcAV leads to the formation of large GcAV, which is also unobserved in canonical autophagy.