Mitochondrial preprotein translocase.

A Role for Tim21 in Membrane-Potential-Dependent Preprotein Sorting in Mitochondria

The mitochondrial inner membrane harbors complexes of the respiratory chain and translocase complexes for preproteins. The membrane potential generated by the respiratory chain is essential for ATP production by the mitochondrial ATP synthase and as a driving force for protein import. It is generally believed that the preprotein translocases just use the membrane potential without getting into ...

Cooperation of Stop-Transfer and Conservative Sorting Mechanisms in Mitochondrial Protein Transport

The mitochondrial inner membrane is a highly protein-rich membrane with central importance for oxidative phosphorylation and metabolite transport. A large number of inner-membrane proteins are synthesized as preproteins with cleavable presequences. Opposing mechanisms of preprotein insertion into the membrane have been debated: stop-transfer with arrest in the inner membrane versus conservative...

Active remodelling of the TIM23 complex during translocation of preproteins into mitochondria.

The TIM23 (translocase of the mitochondrial inner membrane) complex mediates translocation of preproteins across and their insertion into the mitochondrial inner membrane. How the translocase mediates sorting of preproteins into the two different subcompartments is poorly understood. In particular, it is not clear whether association of two operationally defined parts of the translocase, the me...

Dynamic Regulation of Function of the Mitochondrial TIM23 Preprotein Translocase

Mechanistic and Functional Studies of Proteins 1019 Protein import into mitochondria

Mitochondria comprise approx. 1000–3000 different proteins, almost all of which must be imported from the cytosol into the organelle. So far, six complex molecular machines, protein translocases, were identified that mediate this process. The TIM23 complex is a major translocase in the inner mitochondrial membrane. It uses two energy sources, namely membrane potential and ATP, to facilitate pre...