Dealing with membrane stress through CASM.

Compartments of the endolysosomal and secretory pathways encounter diverse insults - from loss of ion gradients and osmotic imbalance to physical membrane disruption - creating a need for rapid, localized surveillance and response systems. Recent work demonstrates that conjugation of ATG8 to single membranes (CASM) provides such specificity via stress-responsive targeting mechanisms that recruit the ATG8 conjugation machinery through pathways distinct from macroautophagy/autophagy. Here, we review recent advances in how membrane stress is sensed, coupled to CASM initiation, and converted into downstream cellular responses.