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Author Spotlight: Detection of Mitophagy in Caenorhabditis elegans and Mammalian Cells Using Organelle-Specific Dyes
Published on: May 19, 2023
VCP/p97 cofactor UBXN1/SAKS1 regulates mitophagy by modulating MFN2 removal from mitochondria
Chantal Mengus1, Melanie Neutzner1, Ana Catarina Pinho Ferreira Bento1
1Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland.
UBXN1 is a VCP cofactor crucial for PINK1/PRKN-dependent mitophagy. Loss of UBXN1 impairs mitochondrial VCP/PRKN translocation and MFN2 removal, hindering mitophagy initiation and maintenance.
Area of Science:
- Cell Biology
- Mitochondrial Dynamics
- Autophagy
Background:
- Mitophagy, PINK1/PRKN-dependent removal of damaged mitochondria, is essential for cellular health.
- The AAA-ATPase VCP/p97 and its cofactors are vital for handling ubiquitinated proteins, including those involved in mitophagy.
- MFN2 removal from mitochondria is a key step preceding PRKN accumulation and subsequent mitophagy.
Purpose of the Study:
- To investigate the role of the VCP cofactor UBXN1/SAKS1 in PINK1/PRKN-dependent mitophagy.
- To elucidate the mechanism by which UBXN1 influences mitochondrial integrity and mitophagic flux.
Main Methods:
- Cellular assays to assess mitochondrial morphology, ATP production, and ER-mitochondrial contact sites.
- Mitochondrial translocation studies of VCP and PRKN in UBXN1-deficient cells.
- Co-immunoprecipitation to determine physical interactions between UBXN1 and PRKN.
- Analysis of MFN2 localization and processing under mitochondrial stress conditions.
Main Results:
- Loss of UBXN1 causes mitochondrial fragmentation, reduced ATP levels, and impaired ER-mitochondrial apposition.
- UBXN1 deficiency hinders VCP and PRKN translocation to mitochondria, diminishing mitophagic flux.
- UBXN1 physically interacts with PRKN, facilitating MFN2 removal from mitochondria.
- MFN2 accumulates in para-mitochondrial blobs in UBXN1-deficient cells, correlating with impaired PRKN recruitment.
Conclusions:
- UBXN1 is a critical VCP cofactor that regulates the initiation and maintenance of PINK1/PRKN-dependent mitophagy.
- UBXN1 facilitates MFN2 removal from mitochondria, a process essential for PRKN translocation and effective mitophagy.
- MFN2 removal involves a specialized mechanism upon mitochondrial stress, with UBXN1 playing a central role.
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