Mitochondrial inner membrane protease promotes assembly of presequence translocase by removing a carboxy-terminal targeting sequence
29.11.2013
Ieva R, Heißwolf AK, Gebert M, Vögtle FN, Wollweber F, Mehnert CS, Oeljeklaus S, Warscheid B, Meisinger C, van der Laan M, Pfanner N.
Nat Commun. 2013;4:2853
More than half of the approximately 1,000 different mitochondrial proteins are synthesized as preproteins in the cytosol with N-terminal presequences. Preprotein transport at the inner membrane is mediated by the presequence translocase (TIM23 complex). We have identified a key step in the biogenesis of this intricate molecular machine that involves the conserved inner membrane protease (IMP). The recently identified Mgr2 subunit of the TIM23 complex carries an unusual C-terminal extension that is required for the efficient targeting of Mgr2 to mitochondria. Upon import this C-terminal targeting signal is cleaved by IMP on the intermembrane space side of the inner membrane. IMP processing of Mgr2 is crucial for the assembly and functionality of Mgr2 in the TIM23 complex.
