ATG16L1 controls mammalian vacuolar proton ATPase

The mechanisms governing mammalian proton pump V-ATPase function are of fundamental and medical interest. The assembly and disassembly of cytoplasmic V₁ domain with the membrane-embedded V₀ domain of V-ATPase is a key aspect of V-ATPase localization and function. Here, we show that the mammalian protein ATG16L1, primarily appreciated for its role in canonical autophagy and in noncanonical membrane atg8ylation processes, controls V-ATPase. ATG16L1 knockout elevated V-ATPase activity, increased V₁ presence on endomembranes, and increased the number of acidified intracellular compartments. ATG16L1’s ability to efficiently bind V-ATPase was required for its inhibitory role in endolysosomal acidification and for control of Mycobacterium tuberculosis infection in mice. These findings uncover a hitherto unappreciated role of ATG16L1 in regulating V-ATPase, a key pump governing acidification and functionality of the endolysosomal system along with its physiological roles.