Navigation Links
Sociable receptors: In pairs, in groups or in a crowd
Date:2/5/2014

This news release is available in German.

When cells migrate in the body, for instance, during development, or when neurons establish new connections, cells need to know where they are going. A 'wrong turn' will generally cause disease or developmental disorders. The cells take direction cues from other cells with which they interact, and which they then repel after a short period of contact. Among those direction cues are ephrin ligands, recognized by Eph receptors on the cell. Together with colleagues from the Max Planck Institute of Molecular Physiology in Dortmund, scientists at the Max Planck Institute of Neurobiology in Martinsried have discovered that Eph receptors must form groups of three or four in order to become active and transmit the signal. Furthermore, the ratio of such multimers to inactive dimers determines the strength of the cellular repulsion response. The new findings help scientists understand how cells communicate and offer a point of departure for studying diseases related to breakdowns in this guidance system.

When people get together, there is usually a lot of interaction. Our cells behave similarly. When cells grow close to each other during development, they need to communicate with the surrounding cells to establish whether they are in the right place in the organism and which cells they should connect with. This communication is especially critical in the brain, where adhesion and repulsion processes between neurons occur continuously. It is only when the right cells connect that something new can be learned, for example. Emerging tumours also must exchange information with the cells around them to be able to grow. "It is of fundamental importance to understand how cells communicate with one another", says Rdiger Klein, Director at the Max Planck Institute of Neurobiology. He has been studying the language of the cells for years together with colleagues in his department. Their research focuses on the so-called Eph receptors and their ephrin ligands.

Cell communication via ephrin/Eph receptors comes into play in most encounters between cells. As a result of this communication, one cell usually repels the other, which continues to grow in another direction. Many such instances of interaction guide the cell to the right place. The guidance system itself the ephrins and Eph receptors are found on the cell surface. When the ephrin and the Eph receptor of two opposing cells meet, they form an ephrin/Eph complex. This triggers cellular processes in one or both of the cells, which eventually cause the detachment of the ephrin/Eph complex and the repulsion of the two cells from one another.

"Many receptor systems have developed a security mechanism to prevent false alarms from triggering the cellular processes", explains Rdiger Klein. "A signal is only transmitted to the cell if two receptor/ligand pairs form a dimer." However, in the case of ephrins and Eph receptors, things are different. Ephrin/Eph complexes form dimers, but often also larger groups on the cell membranes. Scientists were previously not sure how this affects repulsion and repulsive signalling strength.

The neurobiologists in Martinsried and their colleagues from the Max Planck Institute of Molecular Physiology in Dortmund have now been able to artificially trigger and study the formation of groups of Eph receptors in cell culture. The results show that the otherwise usual dimers are inactive when made up of Eph receptors. Only trimers and tetramers triggered the signals that caused cell repulsion. However, the scientists' working hypothesis that a larger group would trigger a stronger signal turned out to be too simple. "It took us quite some time to figure out the system", says Andreas Schaupp, first author of the study. "In fact, it is not the size of each individual group that matters, but the composition of the entire population of groups."

The more trimers and tetramers and the fewer dimers present in the cell membrane, the stronger the repulsion signal. In contrast, a higher abundance of dimers and a smaller number of multimers produce a weaker reaction or none at all. "Thanks to this mechanism, a cell can grade its response from forcing another cell to make a U-turn to simply guiding it past at close range", Rdiger Klein says. This is an important step in understanding how migrating and growing cells navigate, and why this guidance system breaks down in some diseases.


'/>"/>
Contact: Stefanie Merker
merker@neuro.mpg.de
49-898-578-3514
Max-Planck-Gesellschaft
Source:Eurekalert  

Related biology news :

1. Different neuronal groups govern right-left alternation when walking
2. OU research groups awarded NSF grants to expand research and training in science and engineering
3. Shark rules need teeth, groups tell IUCN
4. Video-gaming fish play out the advantages of groups
5. Environmental groups should pool efforts to reach the public
6. 2 distinguishable gene groups detected: 1 normal and 1 problematic
7. Unleashing the power of the crowd
8. Carnegie Mellon researchers develop artificial cells to study molecular crowding and gene expression
9. CU-Boulder helps tap crowds to digitize museum records of bugs and plants
10. Crowdsourcing to kickstart comeback from ash dieback
11. Study sheds light on how cells transport materials along crowded intercellular highways
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Sociable receptors: In pairs, in groups or in a crowd
(Date:3/27/2017)... ROCKVILLE CENTRE, N.Y. , March 27, 2017 ... by Healthcare Information and Management Systems Society (HIMSS) ... Analytics Outpatient EMR Adoption Model sm . In ... top 12% of U.S. hospitals using an electronic ... recognized CHS for its high level of EMR ...
(Date:3/22/2017)...   Neurotechnology , a provider of high-precision ... the release of the SentiVeillance 6.0 ... recognition using up to 10 surveillance, security and ... new version uses deep neural-network-based facial detection and ... a Graphing Processing Unit (GPU) for enhanced speed. ...
(Date:3/16/2017)... , March 16, 2017 CeBIT 2017 - Against identity fraud with ... Reading ... Used combined in one project, multi-biometric solutions provide a crucial ... Used combined in ... ...
Breaking Biology News(10 mins):
(Date:4/20/2017)... 20, 2017  Eli Lilly and Company (NYSE: ... galcanezumab for the prevention of migraine at the American ... place April 22-28, 2017, in Boston ... at AAN, including safety and patient outcomes data for ... a reduction in monthly migraine headache days among patients ...
(Date:4/20/2017)... ... 20, 2017 , ... NetDimensions appoints Bill Mastin, a learning technology veteran, as ... experience in the learning technologies industry, Mastin joins NetDimensions from the New York office ... (LTG). At LEO, Mastin served as SVP of the North America offices and prior ...
(Date:4/20/2017)... ... April 20, 2017 , ... Parallel6™ , the leader ... announced today that they were named one of the 2017 Top 10 eClinical ... developments in the pharmaceutical industry. , “We take pride in honoring Parallel6 as one ...
(Date:4/20/2017)... HACKENSACK, N.J. and PETACH TIKVAH, Israel ... (NASDAQ: BCLI), a leading developer of adult stem cell technologies ... Chief Executive Officer, will present at the Alliance for Regenerative ... Investor Day on Thursday, April 27, 2017 at 09:40 EDT ... Dr. Ralph Kern , MD, MHSc, Chief Medical Officer ...
Breaking Biology Technology: