Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How cells dispose of their waste

24.01.2012
Defective proteins that are not disposed of by the body can cause diseases such as Alzheimer's or Parkinson's.

Scientists at the Max Planck Institute (MPI) of Biochemistry recently succeeded in revealing the structure of the cellular protein degradation machinery (26S proteasome) by combining different methods of structural biology.


The "regulatory particle" (in blue) detects the proteins tagged with ubiquitin and prepares them for degradation. The "core particle" (in red) breaks the proteins down into their single components. Credit: Julio Ortiz / Copyright: MPI of Biochemistry

The results of collaboration with colleagues from the University of California, San Francisco and the Swiss Federal Institute of Technology Zurich (ETH Zürich) represent an important step forward in the investigation of the 26S proteasome. The findings have now been published in Proceedings of the National Academy of Sciences.

At any given point in time, cells may contain only the proteins that are needed at exactly this moment. Otherwise, undesirable reactions can occur which could cause cancer or other diseases. Furthermore, the proteins have to be folded correctly to fulfill their tasks. Misfolded proteins can clump into aggregates, and neurodegenerative diseases such as Alzheimer's or Parkinson's may be the consequence. In order to prevent this, several mechanisms in the body regulate the number of proteins in the cell and degrade proteins if necessary.

"Cellular waste disposal" – the 26S proteasome – plays an important role in protein degradation. First, misfolded and potentially dangerous proteins are tagged with molecules called ubiquitin. The 26S proteasome detects the tagged proteins and breaks them down into small fragments, which are then recycled. Scientists in the team of Wolfgang Baumeister, head of the research department "Molecular Structural Biology" at the MPI of Biochemistry, have now been able to reveal its structure.

Many puzzle pieces lead to one structure

"The structure of the 26S proteasome changes continuously," explained Friedrich Förster, head of the research group "Modeling of Protein Complexes" at the MPI of Biochemistry. "That is why until now it could not be explained by means of traditional approaches, such as only using X-ray crystallography. We had to combine different methods to be successful." Electron microscopy and mass spectrometry helped to reveal the general structure of the 26S proteasome. X-ray crystallography provided detailed insights into specific areas of the molecule. The researchers then used computer software to integrate the different data and generate an overall picture.

Based on these results, the researchers next want to find out how the different mechanisms of protein degradation work in detail. "We have already developed a hypothesis of how exactly the 26S proteasome detects tagged proteins and processes them," said Stefan Bohn, scientist at the MPI of Biochemistry. The complete elucidation of the 26S proteasome and its underlying mechanisms could also be of medical importance: "Cellular waste disposal" is a therapeutic target for cancer und neurodegenerative diseases.

Dr. Wolfgang Baumeister | EurekAlert!
Further information:
http://www.biochem.mpg.de

More articles from Life Sciences:

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

nachricht Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>