A complex of Cox4 and mitochondrial Hsp70 plays an important role in the assembly of the cytochrome c oxidase
17.07.2013
Böttinger L, Guiard B, Oeljeklaus S, Kulawiak B, Zufall N, Wiedemann N, Warscheid B, van der Laan M, Becker T.
Mol Biol Cell. 2013;24(17):2609-19.
The biogenesis of cytochrome c oxidase (complex IV) is a complicated process. Several protein factor mediate the assembly of mitochondria-encoded subunits of the cytochrome c oxidase. However, the biogenesis of nuclear-encoded subunits like Cox4 remained poorly understood. Cox4 is a soluble matrix-localized subunit that is crucial for the assembly of the cytochrome c oxidase. We found that Cox4 is also present in association with the mitochondrial Hsp70 and its co-chaperone Mge1. In the absence of mature complex IV Cox4 arrests at the chaperone system. In a temperature sensitive mutant of mtHsp70 the interaction to Cox4 is lost and the assembly of complex IV affected. We conclude that the Cox4 chaperone complex is required for the efficient formation of the cytochrome c oxidase. Thus, we identified a novel function of mtHsp70 in the assembly of respiratory chain complexes.
