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Control of mitochondrial protein import by pH
Sergey M Grigoriev1, Robert E Jensen, Kathleen W Kinnally
1Division of Basic Sciences, New York University College of Dentistry, New York, NY 10010, USA.
FEBS Letters
|October 11, 2003
Summary
Mitochondrial protein import is hindered by protons. Researchers found that higher proton concentrations reduce the open probability of TOM and TIM23 channels, suggesting TIM23 channel activity limits protein entry into yeast mitochondria.
Area of Science:
- Mitochondrial biology
- Molecular and Cellular Physiology
Background:
- Protein import into mitochondria is crucial for cellular function.
- This process is known to be sensitive to pH, with proton concentration affecting import efficiency.
Purpose of the Study:
- To investigate the pH dependence of mitochondrial protein import.
- To examine the single channel behavior of mitochondrial protein translocation channels (TOM and TIM23) at various pH levels.
Main Methods:
- Utilized patch-clamp techniques to record single channel activity.
- Measured the open probability of TOM and TIM23 channels across a range of pH values.
Main Results:
- Both TOM (translocase of the outer mitochondrial membrane) and TIM23 (translocase of the inner mitochondrial membrane) channels exhibited decreased open probability with increasing proton (H+) concentration.
- The pH dependence of channel activity correlated with the pH dependence of overall protein import.
Conclusions:
- The open probability of the TIM23 channel is a potential limiting factor for the import of nuclear-encoded proteins into the mitochondrial matrix in yeast.
- These findings provide insights into the regulation of mitochondrial protein import by pH.