The ubiquitin kinase PINK1 recruits autophagy receptors to induce mitophagy.
Protein aggregates and damaged organelles are tagged with ubiquitin chains to trigger selective autophagy. To initiate mitophagy, the ubiquitin kinase PINK1 phosphorylates ubiquitin to activate the ubiquitin ligase parkin, which builds ubiquitin chains on mitochondrial outer membrane proteins, where they act to recruit autophagy receptors. Using genome editing to knockout five autophagy receptors in HeLa cells, here we show that two receptors previously linked to xenophagy, NDP52 and optineurin, are the primary receptors for PINK1- and parkin-mediated mitophagy. PINK1 recruits NDP52 and optineurin, but not p62, to mitochondria to activate mitophagy directly, independently of parkin. Once recruited to mitochondria, NDP52 and optineurin recruit the autophagy factors ULK1, DFCP1 and WIPI1 to focal spots proximal to mitochondria, revealing a function for these autophagy receptors upstream of LC3. This supports a new model in which PINK1-generated phospho-ubiquitin serves as the autophagy signal on mitochondria, and parkin then acts to amplify this signal. This work also suggests direct and broader roles for ubiquitin phosphorylation in other autophagy pathways.
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Michael
M
Lazarou
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Danielle A
DA
Sliter
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Lesley A
LA
Kane
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Shireen A
SA
Sarraf
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Chunxin
C
Wang
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Jonathon L
JL
Burman
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Dionisia P
DP
Sideris
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Adam I
AI
Fogel
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
Richard J
RJ
Youle
D001343:Autophagy / Q000502:physiology*; D000071189:Autophagy-Related Protein-1 Homolog; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D063306:Mitophagy / Q000502:physiology*; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015398:Signal Transduction; D035582:Transcription Factor TFIIIA / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D000099202:PTEN-Induced Putative Kinase
D000071189:Autophagy-Related Protein-1 Homolog; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D008869:Microtubule-Associated Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D035582:Transcription Factor TFIIIA; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases; D000099202:PTEN-Induced Putative Kinase; C094297:CALCOCO2 protein, human; C502070:MAP1LC3B protein, human; C409460:OPTN protein, human; C522812:WIPI1 protein, human; C426003:ZFYVE1 protein, human; C111567:parkin protein; C403191:TBK1 protein, human; C484754:ULK1 protein, human