Activation of pro-survival autophagy by a small molecule promoting p62 oligomerisation.

Autophagy is a critical mechanism of cellular quality control, orchestrated by selective autophagy receptor (SAR) proteins. Pharmacologically enhancing the cargo-targeting capacity of SARs presents an attractive but underexplored strategy for the precise therapeutic activation of autophagy. Here, we characterise SQ-1, a small-molecule activator of autophagy that engages the prototypical SAR protein p62/SQSTM1 (sequestosome-1). We show that SQ-1 sensitises p62 to oxidation and promotes its disulphide-mediated oligomerisation in response to mitochondrial reactive oxygen species (ROS). This ROS-dependent activation of p62-mediated selective autophagy enhances the clearance of ROS-generating mitochondria and restores cell viability in models of Niemann-Pick type C1 (NPC1) disease, which is marked by impaired autophagic flux. In summary, the unique mode of action of SQ-1 enables self-regulated autophagy activation, offering a potential therapeutic strategy for lysosomal storage disorders and a broader spectrum of age-related diseases characterised by defective autophagy.