ULK

ULK kinases are the mammalian orthologs of yeast Atg1 and initiate autophagy. ULK1 and ULK2 assemble with FIP200 (RB1CC1), ATG13 and ATG101 into a complex that is inhibited by mTORC1 phosphorylation in nutrient-rich conditions and activated by AMPK when energy is scarce. Activated ULK1 phosphorylates Beclin-1, ATG9, ATG14 and AMBRA1 to nucleate the phagophore. The family also includes ULK3, which acts in Hedgehog signaling through GLI proteins, ULK4, a divergent member with reduced catalytic consensus that is brain-enriched and linked to neurodevelopmental disorders, and the distantly related STK36. The clinical ULK1 inhibitor DCC-3116 tests autophagy blockade in RAS-driven tumors.