Flexible Atg1/ULK complex composition activates selective autophagy for phosphate starvation.

Abstract

The molecular basis for bulk autophagy activation due to a deficiency in essential nutrients such as carbohydrates, amino acids, and nitrogen is well understood. Given autophagy functions to reduce surplus to compensate for scarcity, it theoretically possesses the capability to selectively degrade specific substrates to meet distinct metabolic demands. However, direct evidence is still lacking that substantiates the idea that autophagy selectively targets specific substrates (known as selective autophagy) to address particular nutritional needs. Recently, Gross et al. found that during phosphate starvation (P-S), rather than nitrogen starvation (N-S), yeasts selectively eliminate peroxisomes by dynamically altering the composition of the Atg1/ULK kinase complex (AKC) to adapt to P-S. This study elucidates how the metabolite sensor Pho81 flexibly interacts with AKC and guides selective autophagic clearance of peroxisomes during P-S, providing novel insights into the metabolic contribution of autophagy to special nutritional needs.