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How can mutations in mitochondrial DNA affect ATP production?
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mitochondrion
Mitochondria (red) are found throughout the cytoplasm of almost all eukaryotic cells (cell nucleus is shown in blue; cytoskeleton is shown in yellow).
Mutations in mitochondrial DNA (mtDNA) can significantly impair the production of adenosine triphosphate (ATP), the primary energy currency of the cell.12
The human mitochondrial genome contains 37 genes, 13 of which encode essential components of the electron transport chain (ETC). The ETC is the primary energy-generating system of the cell, where a series of oxidation-reduction reactions drive the phosphorylation of ADP to ATP. Mutations in these genes can lead to:1
- ETC Dysfunction: Defects in the protein components of the ETC directly hinder the transfer of electrons, thereby reducing the efficiency of ATP synthesis.12
- Metabolic Impairment: When ATP production is compromised, cells may experience a buildup of unused metabolic intermediates, which can lead to the production of harmful by-products like lactic acid.2
- Oxidative Stress: Mitochondrial dysfunction often increases the release of reactive oxygen species, which can cause further cellular damage and contribute to cell death.12
The severity of these effects often depends on heteroplasmy, the ratio of normal to mutant mtDNA within a cell. If a significant percentage of mitochondria are abnormal, the affected tissues exhibit impaired energy production and function.13