Mitochondrial ADP/ATP carrier associates with the inner membrane presequence translocase in a stoichiometric manner
14.08.2014
Mehnert CS, Rampelt H, Gebert M, Oeljeklaus S, Schrempp SG, Kochbeck L, Guiard B, Warscheid B, van der Laan M.
J Biol Chem. 2014;289(39):27352-62
The presequence translocase of the inner mitochondrial membrane (TIM23 complex) mediates the import of nuclear-encoded mitochondrial preproteins that carry amino-terminal presequences as targeting information. The energy required for the vectorial movement of preproteins across or into the inner membrane is provided through the coupling of TIM23 to different energy-converting molecular machines, like the ATP-driven import motor or respiratory chain complexes. In this study we demonstrate that the ADP/ATP carrier (AAC) of the inner mitochondrial membrane associates with the TIM23 complex in a stoichiometric manner. Our functional analysis of the newly identified TIM23-AAC supercomplex suggests that AAC may provide energy to TIM23-mediated preprotein import reactions under conditions where mitochondrial ATP levels are limiting and ATP is imported into mitochondria from the cytosol (glycolytic metabolism).
