ULK1 and infection: In the presence of infection or other stresses in macrophages, AMPK senses low cellular energy and is activated; in turn, activated AMPK inhibits mTORC1 phosphorylation on the one hand and activates ULK1 kinase by phosphorylating the Ser317 and Ser777 sites of ULK1, with the latter promoting autophagosome formation by activating ATG9, which was recently shown to lead to the induction of autophagy [39].