Biochemist Peter Walter receives the Paul Ehrlich and Ludwig-Darmstaedter Prize on March 14, 2012 for his achievements in the field of cell biology. Photo: Roche Diagnostics GmbH
Read aloud Body cells are literally crammed with molecules. However, most of them can only fulfill their function if they reach the right place within the cell. How does the cell manage not to sink into chaos? Biochemist Peter Walter has found answers to this question that may help to better understand diseases such as cancer and diabetes mellitus. For this he is today awarded the Paul Ehrlich and Ludwig Darmstaedter Prize? an award unofficially considered the harbinger of the Nobel Prize. You have to imagine the inside of a cell like the city traffic of a metropolis at the end of the day: crowded with big and small vehicles that all want to reach a certain place. Newly formed proteins, sugar molecules and countless other substances need to reach their destination reliably in order to perform their function. If they end up in the wrong place, they can cause considerable damage in the worst case scenario. The situation is particularly complicated for proteins: many of them are not yet completely finished and have to be "finished"? first transported into a specific cell organelle, the endoplasmic reticulum (ER). Only here can the chain of amino acids, which is dictated by the DNA, merge into a functional protein? one speaks of "protein folding".

Faced with these challenges, it's a miracle that cells work so well. How the proteins are sorted by the cell has long been a mystery. The fact that one no longer has to believe in miracles in this respect today is largely due to the German-American biochemist Peter Walter. During his doctoral thesis at Rockefeller University in the laboratory of the late Nobel laureate Günter Blobel he discovered in the early 80s, a sophisticated mechanism by which the cell can control newly formed proteins in the ER: It ensures that the amino acid chain during its synthesis to the ER membrane is delivered.

All proteins are created by joining individual amino acids of a ribosome, the cell's protein factory. The end of this chain, which will finish first, may now have a sequence of amino acids that acts as a signal for a molecular taxi: this taxi attaches itself to the signal sequence of the half-finished protein and "drives" the amino acid chain together with the ribosome Recognition point on the ER. Here, the bond between the taxi and its cargo is released, and the amino acids are channeled through a channel into the ER. The molecular taxi was made by Walter? Signaling Particles? ? short SRP? called.

The SRP is today textbook knowledge and has taken cell biology one step further. For this achievement, Peter Walter will today be the? Paul Ehrlich and Ludwig Darmstaedter Prize? awarded, which is endowed with 100, 000 euros. The price of the Paul Ehrlich Foundation is considered the highest honor that Germany has to award in the field of medicine. It has been presented every year since 1952 on the 14th of March, the birthday of Paul Ehrlich, and has often proved to be the harbinger of a Nobel Prize: since the beginning of the 1990s, nine winners of the Paul Ehrlich and Ludwig Darmstaedter awards have been awarded later considered the Nobel Prize. display

Incidentally, Peter Walter owes an amazing discovery to the SRP to a lucky coincidence: a student had left a false optical filter in a measuring device. Thus, after initial confusion, the SRP, in addition to a protein content, also contains a proportion of ribonucleic acids, a sister molecule of DNA. "It was really a discovery we had to chance and the fact that we stuck to something that did not make any sense, " Walter said in an interview in 2011. "By now, I'm getting quite excited when there's no one Make sense!? Today, the 57-year-old works as a professor at the University of California in San Francisco. Among other things, the next step in protein synthesis currently involves him: controlling the correct protein folding in the ER. Obviously answers to diseases like cancer and type II diabetes are also hidden here.

Part of the award-winning work Peter Walter and Günter Blobel published in 1982 in the journal "Nature" (doi: 10.1038 / 299691a0) © science.de? Maria Bongartz

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