Unc-51-like autophagy activating kinase 1 (ULK1)–autophagy-related 13 (ATG13) is the most upstream autophagy initiation complex that is phosphorylated by mammalian target-of-rapamycin complex 1 (mTORC1) and AMP-activated protein kinase (AMPK) to induce autophagy in asynchronous conditions. However, their phospho-regulation and functions in mitosis and cell cycle remain unknown. Here we show that ULK1-ATG13 complex is differentially regulated throughout the cell cycle, especially in mitosis, in which both ULK1 and ATG13 are highly phosphorylated by the key cell cycle machinery cyclin-dependent kinase 1 (CDK1)/cyclin B. Combining mass spectrometry and site-directed mutagenesis, we found that CDK1-induced ULK1-ATG13 phosphorylation promotes mitotic autophagy and cell cycle progression. Moreover, double knockout (DKO) of ULK1 and ATG13 could block cell cycle progression and significantly decrease cancer cell proliferation in cell line and mouse models. Our results not only bridge the mutual regulation between the core machinery of autophagy and mitosis but also illustrate the positive function of ULK1-ATG13 and their phosphorylation by CDK1 in mitotic autophagy regulation.

Unc-51样自噬激活激酶1（ULK1）–自噬相关13（ATG13）是最上游的自噬起始复合物，被哺乳动物雷帕霉素复合物1（mTORC1）和AMP激活的蛋白激酶（AMPK）磷酸化）在异步条件下诱导自噬。然而，它们的磷酸调节及其在有丝分裂和细胞周期中的功能仍然未知。在这里，我们显示ULK1-ATG13复合物在整个细胞周期中受到差异调节，尤其是在有丝分裂中，其中关键细胞周期机制细胞周期蛋白依赖性激酶1（CDK1）/细胞周期蛋白B高度磷酸化了ULK1和ATG13。结合质谱和定点诱变，我们发现CDK1诱导的ULK1-ATG13磷酸化促进有丝分裂自噬和细胞周期进程。此外，在细胞系和小鼠模型中，ULK1和ATG13的双重敲除（DKO）可以阻断细胞周期进程并显着降低癌细胞的增殖。我们的结果不仅桥接了自噬和有丝分裂的核心机制之间的相互调节，而且说明了ULK1-ATG13的正功能及其在有丝分裂自噬调节中的CDK1磷酸化作用。