Mitochondrial\nProbe for Glutathione Depletion Reveals\nNME3 Essentiality for Mitochondrial Redox Response

Maintenance of the mitochondrial thiol redox state is\nessential\nfor cell survival. However, we lack a comprehensive understanding\nof the redox response to mitochondrial glutathione depletion. We developed\na mitochondria-penetrating peptide, mtCDNB, to specifically deplete\nmitochondrial glutathione. A genome-wide CRISPR/Cas9 screen in tandem\nwith mtCDNB treatment was employed to uncover regulators of the redox\nresponse to mitochondrial glutathione depletion. We identified nucleoside\ndiphosphate kinase 3 (NME3) as a regulator of mitochondrial dynamics.\nWe show that NME3 is recruited to the mitochondrial outer membrane\nwhen under redox stress. In the absence of NME3, there is impaired\nmitophagy, which leads to the accumulation of dysfunctional mitochondria.\nNME3 knockouts depleted of mitochondrial glutathione have increased\nmitochondrial ROS production, accumulate mtDNA lesions, and present\na senescence-associated secretory phenotype. Our findings suggest\na novel role for NME3 in selecting mitochondria for degradation through\nmitophagy under conditions of mitochondrial redox stress.