Figure 4.

Biogenesis and neurodegeneration-associated mutations of the OXPHOS system. The mitochondrial DNA (mtDNA; red) encodes ribosomal RNAs (rRNAs), transfer RNAs (tRNAs) and OXPHOS subunits. Mitochondrial ribosomal proteins, tRNA synthetases, mtDNA repair proteins, dNTP (deoxynucleoside triphosphate) pool-maintaining proteins and proteins mediating mtDNA replication, transcription and translation are all encoded by the nuclear DNA (nDNA; purple). Also, OXPHOS assembly factors (green) and the remainder of the OXPHOS subunits (blue) are nDNA encoded. Mutated genes associated with neurodegeneration are indicated (italic). Gene names are given according to the HGNC (HUGO Gene Nomenclature Committee) standard (see text for details). cyt-c, cytochrome-c biogenesis; Fe-S, iron-sulphur cluster biogenesis; CoQ₁₀, CoQ₁₀ biogenesis.