Kim, HeejeongJeon, Byeong TakKim, Isaac M.Bennett, Sydney J.Lorch, Carolyn M.Viana, Martonio PonteMyers, Jacob F.Trupp, Caroline J.Whipps, Zachary T.Kundu, MondiraChung, SoonkyuSun, XinghuiKhalimonchuk, OlehLee, JaekwonRo, Seung-Hyun2024-04-262021-10-042020-01-01https://doi.org/10.3390/ijms21176130https://hdl.handle.net/20.500.14394/38354Selective autolysosomal degradation of damaged mitochondria, also called mitophagy, is an indispensable process for maintaining integrity and homeostasis of mitochondria. One well-established mechanism mediating selective removal of mitochondria under relatively mild mitochondria-depolarizing stress is PINK1-Parkin-mediated or ubiquitin-dependent mitophagy. However, additional mechanisms such as LC3-mediated or ubiquitin-independent mitophagy induction by heavy environmental stress exist and remain poorly understood. The present study unravels a novel role of stress-inducible protein Sestrin2 in degradation of mitochondria damaged by transition metal stress. By utilizing proteomic methods and studies in cell culture and rodent models, we identify autophagy kinase ULK1-mediated phosphorylation sites of Sestrin2 and demonstrate Sestrin2 association with mitochondria adaptor proteins in HEK293 cells. We show that Ser-73 and Ser-254 residues of Sestrin2 are phosphorylated by ULK1, and a pool of Sestrin2 is strongly associated with mitochondrial ATP5A in response to Cu-induced oxidative stress. Subsequently, this interaction promotes association with LC3-coated autolysosomes to induce degradation of mitochondria damaged by Cu-induced ROS. Treatment of cells with antioxidants or a Cu chelator significantly reduces Sestrin2 association with mitochondria. These results highlight the ULK1-Sestrin2 pathway as a novel stress-sensing mechanism that can rapidly induce autophagic degradation of mitochondria under severe heavy metal stress.UMass Amherst Open Access Policyhttp://creativecommons.org/licenses/by/4.0/autophagyULK1Sestrin2phosphorylationmitochondriaATP5Aarticle