Abstract by Ashari Kannangara
Chemistry and Biochemistry
A BioID approach reveals a network of ATG9A interactions, including an ULK1-independent ATG13 subcomplex that regulates ATG9A trafficking from endosomes
Autophagy is a cellular recycling mechanism that helps cells to maintain cellular homeostasis and survive under stress conditions. ATG9A plays an important role throughout the process of autophagy. In this study, we employ a BioID-based proteomics approach to elucidate the ATG9A interactome. Broadly, these experiments revealed a network of ATG9A interactions with protein complexes within ER, Golgi, and endosomal trafficking pathways. In addition, our data revealed a bi-modal interaction of ATG9A with the ULK1 complex and an ATG13 subcomplex. Specifically, our results suggest that ATG9A interacts with the canonical ULK1 complex and this interaction facilitates the AMPK-mediated phosphorylation of ATG9A at S761. In parallel, CRISPR KO/rescue experiments suggest that ATG9A interacts with an ATG13-ATG101-FIP200 complex independently of ULK1 and this interaction is required for ATG9A to traffic away from its Rab5-positive endosomal pools. Together, these data highlight a direct and functional connection between the canonical ULK1 complex and ATG9A (via pS761 phosphorylation).