Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How proteins find the right path

10.04.2015

Scientists at the University of Konstanz reveal molecular control of protein transport in cells / Publication in “Science”

A package arriving at the wrong address causes confusion, in many cases leading to stress. This concept also applies to protein transport in living cells. The team around the Konstanz-based biologist Professor Elke Deuerling, who also is the speaker for the Collaborative Research Centre “Chemical and Biological Principles of Cellular Proteostasis” (SFB 969), has now discovered exactly what is necessary to prevent erroneous protein transport.


photo of Prof. Dr. Elke Deuerling and Dr. Martin Gamerdinger

Two competing activities ensure that proteins safely arrive at their intended destination – in cell organelles like the mitochondria and the endoplasmic reticulum (ER), in particular. The team succeeded in uncovering that, in contrast to the prevailing view, successful protein transport requires not only the signal recognition particle (SRP), but also the nascent polypeptide-associated complex (NAC). The elucidation of this fundamental cellular process may have far-reaching implications for research on age-related defects and diseases, such as Alzheimer’s. The study’s results were published 10 April 2015 in “Science.”

In 1999, Günter Blobel was awarded the Nobel Prize for Medicine for the discovery of the signal recognition particle (SRP) pathway that sorts and delivers proteins to the ER. Within the SFB 969, Dr. Martin Gamerdinger now was able to prove that also the protein complex NAC is necessary for accurate protein sorting by inhibiting the transport of non-authentic proteins into the ER. “Until now,” states Martin Gamerdinger, “it was generally believed that solely the signal recognition particle fulfills the critical role in correct protein transport by stimulating the process. We discovered, however, that the process also must be inhibited in order to prevent erroneous protein targeting.” Evidence for this antagonistic principle was collected with the help of an experimental set-up using the nematode C. elegans and reducing the level of NAC. Martin Gamerdinger comments: “We observed, that in the absence of NAC, the animals experience stress in the ER as well as in mitochondria and live only half as long.”

Elke Deuerling compares NAC with ticket checkers who let people into football games, concerts or the cinema based on the kind of ticket. This controlling function is crucial because ribosomes that produce proteins tend to bind the membrane of the endoplasmic reticulum unspecifically. Without NAC, a part of the proteins being produced by ribosomes mistakenly end up in the ER. “NAC acts as a shield between the ribosome and the endoplasmic reticulum. Only once a protein leaves the ribosome with the right signal or “ticket” for the ER, the signal recognition particle appears to push aside the NAC complex and the protein can enter the ER. The transport only correctly works when the balance between SRP and the NAC complex is right,” explains Elke Deuerling.

Proteins ending up in the wrong location, not only disturb the homeostasis in the endoplasmic reticulum, but also in mitochondria, because proteins specific to them don’t arrive in the mitochondria, but rather in the endoplasmic reticulum. “This creates an enormous stress in the organism and leads to a drastically shortened lifespan of C. elegans,” says the molecular biologist.

The protein complex NAC is essential for all higher cells, also in humans. For this reason, it was impossible to “turn off” the NAC genes, since this would lead to immediate cell death. Instead of the “knock-out” method, Martin Gamerdinger utilized the “knock-down” principle by simply reducing the NAC levels. Elke Deuerling adds: “The trick was to choose the right model organism, C. elegans. We were able to achieve our results by combining a variety of scientific techniques - biochemical approaches, the establishment of new transgenic C. elegans strains and high-resolution microscopy – and with the additional support of my doctoral student Anne Hanebuth and the applied bioinformatics Junior Professor Tancred Frickey.”

Original Publication:
Martin Gamerdinger, Marie Anne Hanebuth, Tancred Frickey, Elke Deuerling: “The principle of antagonism ensures protein targeting specificity at the endoplasmic reticulum”. In: Science, 10. April 2015, Issue 34, No. 6231.


Contact:
University of Konstanz
Communications and Marketing
Phone: +49 7531 88-3603
E-mail: kum@uni-konstanz.de

Prof. Elke Deuerling
University of Konstanz
Molecular Biology
Universitätsstraße 10
78464 Konstanz
Phone: +49 7531 88-2647
E-mail: elke.deuerling@uni-konstanz.de

Weitere Informationen:

http://www.uni.kn

Julia Wandt | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>