Orchestration of OXPHOS biogenesis through regulation of mitochondrial translation

Mitochondrial gene expression is a remnant of the endosymbiotic origin of the organelle, which contains a complete gene expression system that contributes only a handful of subunits to the complexes driving oxidative phosphorylation (OXPHOS). During evolution, many processes of gene expression in mitochondria have diverged from the bacterial ancestor. A central problem to assemble oxidative phosphorylation complexes is that they contain subunits from two genetic sources. Hence, mechanisms have evolved to synchronize expression of nuclear and mitochondrial genes to avoid problems with stoichiometry, which could hamper their assembly. Here, we will summarize recent insights into how gene expression operates with a focus on the mechanisms related to the control of mitochondrial translation in yeast and human cells.