Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How the Cell Keeps Misdelivered Proteins From Causing Damage in the Cell Nucleus

18.12.2014

Heidelberg researchers study process of marking and cellular waste disposal

In their research on protein quality control, Heidelberg scientists gained new insights into how the cell keeps proteins misdirected into the cell nucleus from causing damage. Their investigations focussed on a complex apparatus on the inner nuclear membrane that detects and marks the misdelivered proteins.

In an international cooperation with researchers from France, Sweden and Canada, the team under the direction of Prof. Dr. Michael Knop at the Center for Molecular Biology of Heidelberg University (ZMBH) demonstrated how the cellular “waste disposal service” is triggered in this process. The results of their research were published in “Nature”.

Cells are quite small, but nevertheless very precisely organised in terms of structure – everything has its place. To find their proper place, proteins bear a type of signal built into their structure. These signals function like addresses, and the intracellular “postal service” delivers them to the correct destination. One of these destinations is the cell nucleus. It contains genomic information – the cell DNA.

The DNA has to be read and decoded into new proteins in order for the cell to divide and respond to its environment. The nuclear proteins ensure this process runs correctly. But what happens when proteins accidently find their way into the cell nucleus even though they do not belong there? “This endangers the reading of the genomic information and under certain conditions threatens the existence of the entire cell,” explains Prof. Knop, who heads the yeast cell and systems biology research group at the ZMBH.

During the course of their investigations, Prof. Knop’s research group developed a new method of detecting the misguided proteins and studying how the cell handles them. In collaboration with two research labs, from Rennes and Stockholm, the Heidelberg team at the ZMBH found that the cell contains a complex apparatus on the inner nuclear membrane, a ubiquitin ligase that participates in protein quality control. The ligase can detect and mark the incorrect proteins. Based on this so-called polyubiquitination, the cell “knows” that this particular protein does not belong in the nucleus and activates cellular waste disposal. A proteasome almost literally swallows and “digests” the marked proteins.

“Until now we assumed that the ubiquitin ligase we studied was linked to a special signal transmission process involved in supplying the cell with amino acids,” says Prof. Knop. “We were all the more surprised when our research showed that they actually do not directly perform this function.” Instead, the ligase triggers the removal of a protein that would disrupt the amino acid supply should it arrive in the nucleus at the wrong time.

The Heidelberg scientist further explains that this “sophisticated control mechanism” also works with various other proteins. If they are not delivered correctly, the ubiquitin ligase sets off the process of removing the misdirected proteins from the cell nucleus and the nuclear membrane. Prof. Knop: “But this question still remains: How can this ubiquitin ligase tell whether the proteins have landed in the right or the wrong place?”

Michael Knop also heads the cell morphogenesis and signal transduction working group at the German Cancer Research Center (DKFZ). The researchers from Heidelberg University and the DKFZ collaborated in this study with scientists from the National Centre for Scientific Research in Rennes and the University of Rennes, the Stockholm University, the European Molecular Biology Laboratory (EMBL) in Heidelberg and the University of Toronto.

Original publication:
A. Khmelinskii, E. Blaszczak, M. Pantazopoulou, B. Fischer, D.J. Omnus, G. Le Dez, A. Brossard, A. Gunnarsson, J.D. Barry, M. Meurer, D. Kirrmaier, C. Boone, W. Huber, G. Rabut, P.O. Ljungdahl, M. Knop: Protein quality control at the inner nuclear membrane, Nature 516, 410-413 (18 December 2014), doi: 10.1038/nature14096

Contact:
Prof. Dr. Michael Knop
Center for Molecular Biology of Heidelberg University
Phone: +49 6221 54-4213
m.knop@zmbh.uni-heidelberg.de

Communications and Marketing
Press Office, phone: +49 6221 54-2311
presse@rektorat.uni-heidelberg.de

Weitere Informationen:

http://www.zmbh.uni-heidelberg.de/knop

Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>