Mgr2 promotes coupling of the mitochondrial presequence translocase to partner complexes
21.05.2012
Gebert M, Schrempp SG, Mehnert CS, Heißwolf AK, Oeljeklaus S, Ieva R, Bohnert M, von der Malsburg K, Wiese S, Kleinschroth T, Hunte C, Meyer HE, Haferkamp I, Guiard B, Warscheid B, Pfanner N, van der Laan M.
J Cell Biol. 2012;197(5):595-604.
The transport of mitochondrial precursor proteins with N-terminal presequences across or into the inner mitochondrial membrane is mediated by the presequence translocase (TIM23 complex). The conserved TIM23 core complex associates with the Tim21 protein, which mediates the coupling of this machinery to the translocase of the outer membrane (TOM complex) and to the respiratory chain. We identified the inner mitochondrial membrane protein Mgr2 as a new component of the TIM23 complex that is required for the recruitment of Tim21. Deletion of the MGR2 gene in the baker's yeast Saccharomyces cerevisiae leads to strongly reduced cell growth at elevated temperature, impaired TOM-TIM23 coupling and a defect in the import of presequence proteins. These findings demonstrate that Mgr2 is a novel coupling factor of the TIM23 machinery that is important for the effective protein import.
