The V-ATPase complex regulates non-canonical Atg8-family protein lipidation through ATG16L1 recruitment.

Conjugation of the Atg8 (autophagy related 8) family of ubiquitin-like proteins to phospholipids of the phagophore is a hallmark of macroautophagy/autophagy. Consequently, Atg8 family members, especially LC3B, are commonly used as a marker of autophagosomes. However, the Atg8 family of proteins are not found solely attached to double-membrane autophagosomes. In non-canonical Atg8-family protein lipidation they become conjugated to single membranes. We have shown that this process is triggered by recruitment of ATG16L1 by the vacuolar-type H+-translocating ATPase (V-ATPase) proton pump, suggesting a role for pH sensing in recruitment of Atg8-family proteins to single membranes.