ESCRT recruitment to damaged lysosomes is dependent on the ATG8 E3-like ligases

Abstract

SUMMARYThe endosomal sorting complex required for transport (ESCRT) machinery plays an essential role in the sealing of endolysosomal membranes damaged by pathogenic, chemical or physical stress. How membrane damage is sensed by the cell and then translated into the recruitment of the ESCRT machinery is largely unknown. Here, we show that damage-dependent translocation of the autophagy ATG8 E3-like ligases to lysosomal membranes acts as the catalyst for ESCRT recruitment. Leakage of protons or calcium from perforated lysosomes induces V-ATPase-dependent or sphingomyelin-dependent recruitment of the ATG16L1-ATG5-ATG12 or TECPR1-ATG5-ATG12 E3-like complex, respectively. We show that E3-like complex-dependent recruitment of the ATG5-ATG12 conjugate to the damaged membrane is an essential prerequisite to ESCRT recruitment. At the damaged membrane ATG5-ATG12 plays both a conjugation-dependent and conjugation-independent role in stabilizing the calcium sensor, ALG-2, and recruiting the downstream repair complex. For the former scenario, we demonstrate that LC3B binds directly to ALG-2 in a Ca2+dependent manner. This places the ATG8 E3-like ligases in the role of damage sensors for ESCRT- mediated membrane repair.GRAPHICAL ABSTRACT