A team of researchers develops a new method that enables the identification of proteins imported into mitochondria
Eukaryotic cells contain thousands of proteins, which are distributed to different cellular compartments with specific functions. A German-Swiss team of scientists led by Prof. Dr. Bettina Warscheid from the University of Freiburg and Prof. Dr. André Schneider from the University of Bern has developed the method "ImportOmics".
This method enables the scientists to determine the localization of proteins that are imported via specific entry "gates" into distinct membrane-bound compartments, so-called organelles. Knowing the exact localization of individual proteins, the route they take to reach their destination, and the overall composition of cellular compartments is important for understanding fundamental mechanisms of cell biology.
This is the prerequisite to understand disease mechanisms that rely on defective cellular functions. The scientists present their work in the current issue of the journal "Nature Communications".
The research team developed the method to define the mitochondrial protein inventory of the single-cell parasite Trypanosoma brucei. The parasite contains a single mitochondrion, which is essential for growth and survival. The mitochondrion is surrounded by two membranes and houses more than thousand proteins. The exact protein composition, however, has not yet been established.
The majority of these proteins are synthesized in the cellular fluid, the cytosol, and need to cross the outer membrane of the mitochondrion before they are sorted to their final destination. To this end, the outer membrane is equipped with a central gate, the so-called archaic translocase of the mitochondrial outer membrane (ATOM).
The scientists exploited this gate to define the entirety of the mitochondrial proteins imported from the cytosol. They engineered cells to express reduced levels of ATOM40, the pore-forming component of the ATOM complex, thereby blocking the protein import into the mitochondrion.
The research team used quantitative mass spectrometry to compare the levels of proteins in mitochondria with defective and with undisturbed protein import. As a result, the scientists identified 1,120 proteins, including more than 300 proteins that, so far, had not been associated with the mitochondrion of the parasite.
In addition, they showed that ImportOmics is applicable to systematically analyze different cellular protein import systems. This is exemplified for the import of proteins into the outer mitochondrial membrane and into the mitochondrial intermembrane space. Furthermore, scientists can use this method to analyze the composition of other organelles of the parasite as well as of other organisms.
Bettina Warscheid is head of the Department of Biochemistry and Functional Proteomics at the Institute of Biology II and member of the Cluster of Excellence BIOSS Centre for Biological Signalling Studies at the University of Freiburg.
Zoom-in of an electrospray capillary (left) transferring proteins into the orifice of a mass spectrometer (right). Using this technology, the scientists analyzed mitochondria with a "gate" closed for proteins (cartoon) at molecular level.
Source: Christian D. Peikert
Christian D. Peikert, Jan Mani, Marcel Morgenstern, Sandro Käser, Bettina Knapp, Christoph Wenger, Anke Harsman, Silke Oeljeklaus, André Schneider* and Bettina Warscheid* (2017): Charting Organellar Importomes by Quantitative Mass Spectrometry. Nature Communications. DOI: 10.1038/NCOMMS15272 (*These authors contributed equally.)
Prof. Dr. Bettina Warscheid
Institut für Biologie II
Rudolf-Werner Dreier | Albert-Ludwigs-Universität Freiburg im Breisgau
Mass spectrometry sheds new light on thallium poisoning cold case
14.12.2018 | University of Maryland
Protein involved in nematode stress response identified
14.12.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy