Importing Mitochondrial Proteins: Machineries and Mechanisms

Review
Importing Mitochondrial Proteins: Machineries and Mechanisms

Agnieszka Chacinska1,2, Carla M. Koehler3, Dusanka Milenkovic1, 2, Trevor Lithgow4 and Nikolaus Pfanner1, 2,

1Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany

2Centre for Biological Signalling Studies, Universität Freiburg, 79104 Freiburg, Germany

3Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA

4Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia

Most mitochondrial proteins are synthesized on cytosolic ribosomes and must be imported across one or both mitochondrial membranes. There is an amazingly versatile set of machineries and mechanisms, and at least four different pathways, for the importing and sorting of mitochondrial precursor proteins. The translocases that catalyze these processes are highly dynamic machines driven by the membrane potential, ATP, or redox reactions, and they cooperate with molecular chaperones and assembly complexes to direct mitochondrial proteins to their correct destinations. Here, we discuss recent insights into the importing and sorting of mitochondrial proteins and their contributions to mitochondrial biogenesis.