The electrochemical transmission of the proton-motive force in mitochondrial reticulum

Authors

• KD Patel
• B Glancy
• RS Balaban

Abstract

In skeletal myocytes, mitochondria from an interconnected, regular network that may function to distribute cellular energy from areas of production to areas of utilization called the mitochondrial reticulum (MR). Within the MR, the I-Band segments (IBS) traverse the cell and form a contiguous matrix with the mitochondrial segments at the periphery (PS) of the cell. An electrical coupling between the PS and IBS via the matrix has been demonstrated. In addition, oxidative phosphorylation complexes that generate the proton motive force (PMF) are preferentially located in the PS, while Complex V, which utilizes the PMF, is primarily located along the IBS. This has led to the hypothesis that PS can support the production of ATP in the IBS by maintaining the potential energy available to produce ATP deep in the muscle cell via conduction of the PMF down the IBS. However, the mechanism of transmitting the PMF down the IBS is poorly understood. This theoretical study was undertaken to establish the physical limits governing IBS conduction as well as potential mechanisms for balancing the protons entering the matrix along the IBS with the ejection of protons in the PS.

Scientific Focus Area: Biomedical Engineering and Biophysics

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