ATG13 is a critical autophagy factor required for autophagosome formation and serves as a key component of the ULK1 kinase complex 1. The protein functions as an adaptor molecule within the autophagy initiation complex, which consists of ULK1, ATG13, RB1CC1/FIP200, and ATG101 12. ATG13 is subject to complex regulation through linear ubiquitination by the LUBAC E3 ligase complex and deubiquitination by OTULIN, which controls both autophagy initiation and maturation 3. Beyond its role in canonical autophagy, ATG13 contributes to selective autophagy processes, including mitophagy and ferroptosis 4. The protein facilitates ULK1 complex localization to autophagosome formation sites, where it coordinates with autophagy receptors like NDP52 and TBK1 to enable focal ULK1 activation 2. ATG13 also plays roles in specialized cellular contexts, including decidual macrophage residence during pregnancy through autophagy-dependent mechanisms 5. Recent evidence suggests ATG13 functions extend beyond the traditional ULK1 complex, as it can bind additional partners including ATG8 family proteins and acidic phospholipids, indicating broader regulatory functions in autophagy 1. The protein's regulation and activity are essential for proper autophagosome biogenesis and cellular homeostasis.