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Reconstitution of Msp1 Extraction Activity with Fully Purified Components
Published on: August 10, 2021
The AAA-ATPase p97 is essential for outer mitochondrial membrane protein turnover
Shan Xu1, Guihong Peng, Yang Wang
1Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD 21201, USA.
Molecular Biology of the Cell
|December 2, 2010
Summary
The AAA-ATPase p97 (also known as p97) facilitates the degradation of outer mitochondrial membrane proteins, Mcl1 and Mfn1, by regulating their retrotranslocation to the cytosol for proteasomal processing.
Area of Science:
- Mitochondrial biology
- Protein degradation pathways
- Cellular homeostasis
Background:
- The ubiquitin/proteasome system regulates outer mitochondrial membrane (OMM) protein turnover.
- The precise mechanism for proteasome-dependent degradation of OMM proteins remains largely unknown.
- Several components involved in this process have been identified, but their interplay is unclear.
Purpose of the Study:
- To elucidate the mechanism of proteasome-dependent degradation of OMM-associated proteins.
- To investigate the role of the AAA-ATPase p97 in the turnover of OMM proteins Mcl1 and Mfn1.
Main Methods:
- Biochemical assays were employed to study protein degradation.
- Imaging techniques, including photoactivable GFP-fused Mcl1 localization, were used.
- In vitro assays were performed to confirm p97's direct role in Mcl1 retrotranslocation.
Main Results:
- The AAA-ATPase p97 is essential for the proteasomal degradation of Mcl1 and Mfn1.
- p97 mediates the retrotranslocation of Mcl1 from the OMM to the cytosol.
- This retrotranslocation is dependent on the ATPase activity of p97 and occurs before or concurrently with proteasomal degradation.
Conclusions:
- p97 plays a direct and essential role in the degradation pathway of OMM-associated proteins.
- p97 acts as a novel component facilitating the removal of OMM proteins via retrotranslocation.
- The findings clarify a key step in the cellular process of mitochondrial protein turnover.
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