Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mitochondria Separate Their Waste

29.11.2013
Freiburg researcher shows that cellular power plants collect and break down damaged molecules

In order to protect themselves from harmful substances, cells need to keep the mitochondria – the boiler room, so to speak – shipshape. Up to now, it was unclear whether this housekeeping work involves sorting out defective proteins when they digest mitochondria.


Yeast cells digest their mitochondria in long-time cultures. This process is called mitophagy. Proteins that are digested at a different speed are marked with a fluorescent dye. (© Joern Dengjel)

Dr. Joern Dengjel from the Center for Biological Systems Analysis (ZBSA), Freiburg Institute for Advanced Studies (FRIAS), and the Cluster of Excellence BIOSS Centre for Biological Signalling Studies of the University of Freiburg has now discovered in collaboration with researchers from the Hebrew University in Jerusalem, Israel, that the proteins are sorted out during the constant fusion and fission of mitochondria. The team published their findings in the journal Nature Communications.

The process of mitophagy, in which tiny digestive bubbles surround the mitochondria, serves to recycle waste for the cell. Damaged proteins can no longer carry out their function correctly and need to be broken down. Errors in the digestion of mitochondria appear in old age and in the case of neurodegenerative diseases like Parkinson’s and Alzheimer’s. A better understanding of mitophagy could be the key to counteracting the faulty degradation of cellular components, potentially enabling researchers to develop new therapies for neurodegenerative diseases.

In contrast to bacteria, yeast cells posses mitochondria and are also easy to grow in the laboratory. The researchers used yeasts to observe the processes of mitophagy. Dr. Hagai Abeliovich from the Hebrew University developed a new method for making yeast cells digest mitochondria. Currently, researchers accomplish this by placing stress on the cells with chemicals.

With the new method, yeast cells in long-term cultures begin digesting mitochondria of their own accord – as soon as they have used up all available nutrients. During mitophagy Dengjel succeeded in measuring whether all proteins inside the mitochondria were broken down at the same speed. Indeed, the cell broke down some proteins more quickly than others. When he observed the cells under a fluorescence microscope, he ascertained that the marked proteins in the mitochondria also behaved differently. They appear to be sorted.

The rules by which the sorting is carried out are as yet unknown. However, the researchers demonstrated that mitochondrial dynamics are involved: Mitochondria fuse and divide constantly, forming a network in the process. Genetically modified yeasts that lack these dynamics but form small, round mitochondria exhibit no sorting of the proteins. “The damaged proteins are sorted slowly into an area of the network with each fusion and fission. This mitochondrion is marked and broken down,” says Dengjel. In other words, mitophagy plays the role of garbage collector, separating and recycling waste for the cell. Now Dengjel wants to find out what characterizes the proteins that are sorted out.

Original publication:
H. Abeliovich, M. Zarei, K.T.G. Rigbolt, R.J. Youle and J. Dengjel (2013) Involvement of mitochondrial dynamics in the segregation of mitochondrial matrix proteins during stationary phase mitophagy, Nature Communications 4, Nr. 2789 doi:10.1038/ncomms3789
Contact:
Dr. Jörn Dengjel
Center for Biological Systems Analysis (ZBSA)
Freiburg Institute for Advanced Studies (FRIAS)
BIOSS Centre for Biological Signalling Studies
Universität Freiburg
Tel.: 0761/203-97208
E-Mail: joern.dengjel@frias.uni-freiburg.de

Dr. Jörn Dengjel | Universität Freiburg
Further information:
http://www.uni-freiburg.de

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

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 “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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

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

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>