FIGURE 1.

Mito-nuclear crosstalk in mitochondrial functions and energy production. (A) Mitochondria rely on coordinated functions of nuclear and mitochondrial genomes. Vast majority of the genes required for mitochondrial functions are encoded by the nuclear genome. These proteins are translated in the cytoplasmic compartment and transported into the mitochondrion post-translationally with a mitochondrial targeting signal. Products of both genomes are required for producing cellular energy in the form of ATP through OXPHOS. As a by-product of OXPHOS mitochondria produces reactive oxygen species (ROS) which are detoxified by antioxidants. mt-aaRSs, mitochondrial aminoacyl-tRNA synthetases; mt-RPs, mitochondrial ribosomal proteins. (B) OXPHOS takes place at the inner mitochondrial membrane and it comprises five enzyme complexes. Both nuclear and mitochondrial encoded proteins are required for OXPHOS complexes I and III-V, as complex II contains only nuclear encoded subunits. Complexes I-IV and two electron carriers form the respiratory chain which generates a proton gradient used by complex V to generate ATP.