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Assessment of Open Probability of the Mitochondrial Permeability Transition Pore in the Setting of Coenzyme Q Excess
Published on: June 1, 2022
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Regulation of mitochondrial proteostasis by the proton gradient
Maria Patron1, Daryna Tarasenko2, Hendrik Nolte1
1Max Planck Institute for Biology of Ageing, Cologne, Germany.
The EMBO Journal
|August 1, 2022
Summary
Mitochondria regulate protein turnover via the AFG3L2 protease, controlled by the proton gradient and TMBIM5. This process adapts mitochondrial function to cellular energy needs, protecting against oxidative damage.
Area of Science:
- Mitochondrial biology
- Cellular metabolism
- Proteostasis
Background:
- Mitochondria dynamically adjust their proteome to meet varying energetic demands.
- Mitochondrial proteases are increasingly recognized as critical regulators of these adaptive responses.
- Understanding how mitochondria sense and respond to energetic status is crucial for cellular health.
Purpose of the Study:
- To investigate the regulation of the mitochondrial m-AAA protease AFG3L2 by the mitochondrial proton gradient.
- To identify novel regulators of mitochondrial proteases and their role in cellular adaptation.
- To elucidate the interplay between mitochondrial calcium, energy status, and proteome remodeling.
Main Methods:
- Multiproteomic analysis to study mitochondrial proteome dynamics.
- Biochemical assays to characterize TMBIM5 as a Ca2+/H+ exchanger.
- Inhibition and degradation studies of TMBIM5 and AFG3L2.
Main Results:
- Demonstrated regulation of AFG3L2 protease activity by the mitochondrial proton gradient.
- Identified TMBIM5 as a mitochondrial inner membrane Ca2+/H+ exchanger that inhibits AFG3L2.
- Showed that TMBIM5 degradation under persistent hyperpolarization activates AFG3L2, leading to proteome remodeling and Complex I breakdown.
- Observed that TMBIM5 limits mitochondrial hyperpolarization and ensures cell survival and respiration.
Conclusions:
- TMBIM5 integrates mitochondrial calcium signaling and energy status to regulate AFG3L2 protease activity.
- AFG3L2-mediated proteome remodeling, including Complex I degradation, protects mitochondria from oxidative damage during hyperpolarization.
- This regulatory axis reshapes the mitochondrial proteome and adjusts cellular metabolism in response to energetic challenges.
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