Abstract
Despite their importance as signaling hubs, the function of mitochondria-ER contact sites in mitochondrial quality control pathways remains unexplored. Here we describe a mechanism by which Mfn2, a mitochondria-ER tether, gates the autophagic turnover of mitochondria by PINK1 and parkin. Mitochondria-ER appositions are destroyed during mitophagy, and reducing mitochondria-ER contacts increases the rate of mitochondrial degradation. Mechanistically, parkin/ PINK1 catalyze a rapid burst of Mfn2 phosphoubiquitination to trigger p97-dependent disassembly of Mfn2 complexes from the outer mitochondrial membrane, dissociating mitochondria from the ER. We additionally demonstrate that a major portion of the facilitatory effect of p97 on mitophagy is epistatic to Mfn2 and promotes the availability of other parkin substrates such as VDAC1. Finally, we reconstitute the action of these factors on Mfn2 and VDAC1 ubiquitination in a cell-free assay. We show that mitochondria-ER tethering suppresses mitophagy and describe a parkin-/PINK1-dependent mechanism that regulates the destruction of mitochondria-ER contact sites.
| Original language | English |
|---|---|
| Article number | e32866 |
| Journal | eLife |
| Volume | 7 |
| DOIs | |
| Publication status | Published - 20.04.2018 |
Funding
This work was supported by an operating grant from the Canadian Institutes for Health Research (CIHR) to EAF. GLM was supported by a Canada Graduate Scholarship from the CIHR, and an award from the Montreal Neurological Institute and Desjardins Foundation. We would like to thank Dr Heidi McBride (McGill), Dr Julien Prudent (MRC, Cambridge, UK) and Dr Atsushi Tanaka (Yamagata University, Yamagata, Japan) for stimulating discussions concerning the data presented herein. We are grateful to Dr Matthew Tang for technical advice regarding mtKeima acquisition experiments, stable cell line creation and cell sorting, Dr Marta Vranas for technical help and advice concerning the in organello ubiquitination assay, and Dr Adele Tufford for discussions regarding statistical analyses. We also thank Jeannie Mui and the Facility for Electron Microscopy Research (McGill) for TEM sample processing and technical advice. Proteomic analyses for the GST-Ub pulldown were performed by the Centre for Advanced Proteomics Analyses at the Institut de la Recherche en Immuno-logie et Cancérologie (Montreal, QC), a Node of the Canadian Genomic Innovation Network that is supported by the Canadian Government through Genome Canada. The pCMV-TOM70-2xFLAG-4xUb plasmid was a kind gift from Dr. Xinde Zheng (Salk Institute). The antibodies against MCU, MICU1 and MICU2, as well as the Mfn2 and Mfn1-HA plasmids, were kind gifts from Dr. Heidi McBride. All cell lines and reagents generated by the Montreal Neurological Institute (MNI) IPSC/ CRISPR Platform are available without restriction upon request through the Platform under the Open Science Policy of the MNI.
UN SDGs
This output contributes to the following UN Sustainable Development Goals (SDGs)
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SDG 3 Good Health and Well-being
Research Areas and Centers
- Research Area: Medical Genetics
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