Dr. Stefanie Merker

Phone:+49 89 8578-3514

Prof. Dr. Rüdiger Klein

Phone:+49 89 8578-3151Fax:+49 89 8578-3152

Original publication

Andreas Schaupp, Ola Sabet, Irina Dudanova, Marion Ponserre, Philippe Bastiaens, Rüdiger Klein

Cell Biology . Neurosciences

Sociable receptors: in pairs, in groups or in a crowd

The proportion of different receptor groups in the cell membrane determines whether cell repulsion takes place

February 05, 2014

<p>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.</p>
<p>&nbsp;</p> Zoom Image





“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.


loading content