Featured Research

from universities, journals, and other organizations

Sociable receptors: Cells take clues from other cells to direct behavior

Date:
February 5, 2014
Source:
Max-Planck-Gesellschaft
Summary:
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. Scientists have discovered that Eph receptors must form groups of three or four in order to become active and transmit the signal.

Countless Eph receptors (green) can be found on the surface of this neuron. When they are artificially induced to form groups, the nerve process, or axon (red tip), withdraws.
Credit: © MPI of Neurobiology / Dudanova

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 tumors 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 Rüdiger 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 Rüdiger 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," Rüdiger 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.


Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.


Cite This Page:

Max-Planck-Gesellschaft. "Sociable receptors: Cells take clues from other cells to direct behavior." ScienceDaily. ScienceDaily, 5 February 2014. <www.sciencedaily.com/releases/2014/02/140205103651.htm>.
Max-Planck-Gesellschaft. (2014, February 5). Sociable receptors: Cells take clues from other cells to direct behavior. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2014/02/140205103651.htm
Max-Planck-Gesellschaft. "Sociable receptors: Cells take clues from other cells to direct behavior." ScienceDaily. www.sciencedaily.com/releases/2014/02/140205103651.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How to Make Single Serving Smoothies: Howdini Hacks

How to Make Single Serving Smoothies: Howdini Hacks

Howdini (July 24, 2014) — Smoothies are a great way to get in lots of healthy ingredients, plus they taste great! Howdini has a trick for making the perfect single-size smoothie that will save you time on cleanup too! All you need is a blender and a mason jar. Video provided by Howdini
Powered by NewsLook.com
Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) — An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) — The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Tyrannosaur Pack-Hunting Theory Aided By New Footprints

Newsy (July 24, 2014) — A new study claims a set of prehistoric T-Rex footprints supports the theory that the giant predators hunted in packs instead of alone. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins