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Chopped, trapped or tacked--protein translocation into the IMS of mitochondria

Johannes M Herrmann1, Kai Hell

  • 1Institut für Physiologische Chemie, Universität München, Butenandtstrasse 5, 81377 Munich, Germany. hannes.herrmann@bio.med.uni-muenchen.de

Trends in Biochemical Sciences
|April 9, 2005
PubMed

All proteins of the intermembrane space (IMS) of mitochondria are synthesized in the cytosol. The mechanisms by which these polypeptides are transported into the IMS are strikingly different from other protein-translocation processes in the cell. Recent studies suggest that IMS proteins reach their destination by three alternative principles that differ in the energy sources employed to drive the translocation reactions. The first class of proteins uses both hydrolysis of matrix ATP and the electrochemical potential of the inner membrane. The second class depends on the energy gain of protein folding, and the third on the association of the proteins to high-affinity binding sites in the IMS.

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