Proteins Distributed In Different Mitochondrial Subcompartments Mapped For The First Time!

The power house of the cell, Mitochondria, transforms the energy stored in nutrients so that cells can use it. If this function is disturbed, many different diseases can develop that often affect organs with a high metabolism, like the brain or the heart.

The mitochondrial proteome comprises ~1000 (yeast)–1500 (human) different proteins, which are distributed into four different subcompartments. The sublocalization of these proteins within the organelle in most cases remains poorly defined.

In the past decade, extensive proteomic studies of purified organellar fractions have generated large high quality compendia of mitochondrial proteins for various organisms ranging from 850 proteins in yeast to more than 1500 proteins in human.

However, knowledge about specific protein sublocalization to one of the four subcompartments, the outer (OM) and inner membrane (IM) and the two soluble compartments intermembrane space (IMS) and matrix, in which these proteins fulfill their dedicated tasks, is limited.

Now, a team at the University of Freiburg led by Prof. Dr. Chris Meisinger and Dr. Nora Vögtle from the Institute of Biochemistry and Molecularbiology have collaborated with scientists from the Leibniz Institute for Analytical Sciences (ISAS) in Dortmund to successfully map the landscape of proteins in the different reaction chambers, or

subcompartments, of mitochondria for the first time.

Using isolated mitochondria from baker’s yeast, the groups of researchers were able to apply various fractionation methods to meticulously isolate the proteins in each compartment and hence successfully map virtually the entire protein landscape of mitochondria.

In the course of their research, the scientists from the University of Freiburg were also able to discover more than 200 additional proteins that had previously not been attributed to mitochondria.

Their published study could thus serve the international research community as a basis for studying the potential new functions of mitochondria and for better understanding not only the central biochemical processes in cells, but also the development of many diseases.