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The Import Business of Cellular Power Plants
07 January 2011
Scientists from Freiburg’s two Excellence Institutions Centre for Biological Signalling Studies (BIOSS) and Spemann Graduate School of Biology and Medicine (SGBM) have discovered a new signaling path in cells: a mechanism which enables the transport of proteins into mitochondria to be adjusted depending on the current metabolic state of the cell. The results of this study were published in the renowned scientific journal "Cell".
Mitochondria are the power plants of the cells. They transform energy taken up through nourishment into a form the cells can use for a multitude of necessary metabolic reactions. In addition, mitochondria are responsible for triggering programmed cell death. It has long been known that illnesses like diabetes, heart disease, and tumors can be traced back to dysfunctions in these cellular organelles. Mitochondria possess around 1,000 different proteins, most of which are initially produced in the cytosol. From there they are imported into the organelle.
A research team led by Prof. Dr. Chris Meisinger from the Institute of Biochemistry and Molecular Biology of the University of Freiburg has now discovered that the main port of entry for these proteins is changed in various ways by cytosolic signaling proteins depending on the metabolic state of the cell, thus regulating the intake of proteins into mitochondria. Mitochondria are descended from bacteria and still possess many of their characteristics today. Researchers were thus long convinced that these organelles act with a high degree of autonomy in higher cells, hardly communicating with other cellular compartments at all. The results of the research project suggest that many more communication paths between mitochondria and the rest of the cell are waiting to be discovered.
“Regulation of Mitochondrial Protein Import by Cytosolic Kinases.” O. Schmidt, A. Harbauer, S. Rao, B. Eyrich, R. Zahedi, D. Stojanovski, B. Schönfisch, B. Guiard, A. Sickmann, N. Pfanner, and C. Meisinger.