Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hungry cells on the move

07.09.2016

Researchers discover a signaling pathway that enables cells to reach their destinations through repulsion

When cells grow and divide, they come into contact with other cells. This happens not only during development and regeneration and after injury, but also during cancer growth and the formation of metastases.


Ephrins (blue) and Ephs (red) form complexes (yellow) at cell contact points. To enable the cells to separate from each other, they are pulled into one of the cells with the help of the signalling proteins Tiam and Rac.

Credit: MPI of Neurobiology/Gaitanos

When cells come into contact with each other in this way, information is exchanged by proteins, which are embedded in the cell membranes and form tight lock-and-key complexes with each other. These connections must be severed if the cells want to transmit a repulsion signal. It appears that the fastest way to do this is for the cells to engulf the protein complex from the membrane of the neighbouring cell. Scientists from the Max Planck Institute of Neurobiology in Martinsried have now identified the molecules that control this process.

Development is an extremely rapid process. Increasing numbers of cells are formed which must find their correct position in the body, clearly demarcate themselves from each other to form tissue, or - as is the case in the nervous system - establish contact with partner cells in remote locations. "The crowding is accompanied by orderly pushing and shoving," says Rüdiger Klein, whose Department at the Max Planck Institute of Neurobiology studies how cells get their bearings.

"A popular way for one cell to show another which direction to take is for it to repel the other cell following brief contact." According to the scientists' observations, the cells do not exactly treat each other with kid gloves and even go so far as to engulf entire pieces from the membranes of other cells.

When cells come into contact with each other, ephrin and Eph receptors are often involved. These proteins are located on the surface of almost all cells. When two cells meet, their ephrin and Eph receptors connect to form tight ephrin/Eph complexes. These complexes then trigger the repulsion process through intracellular signalling pathways.

"This is where the problem arises, as it appears that the cells then want to separate as quickly as possible - however, the two cells are attached to each other through the tight ephrin/Eph complex," explains Klein. So the cells do something else: they extend their own cell membranes so far over the individual complexes that the complex and the surrounding membrane detaches from the neighbouring cell and is fully incorporated into the cell.

The Max Planck researchers discovered as early as 2003 that cells can use this process, known as endocytosis, to separate from each other. Thanks to progress made in molecular biology since then, they have now managed to show how the process is controlled in detail.

With the help of a series of genetic modifications and the targeted deactivation of individual cell components, the scientists succeeded in demonstrating that Tiam signalling proteins are activated through the formation of the ephrin/Eph complex.

As a result, Rac enzymes become active which, in turn, cause the engulfment of the ephrin/Eph complexes by the cell membrane through the local restructuring of the actin cytoskeleton. If one of these components is missing, this engulfing process through endocytosis is blocked and the cells do not repel each other but remain attached.

The clarification of this signalling pathway is important, as it provides a better understanding of the development of neuronal networks and other organ systems. The findings are also of considerable interest for cancer research: thanks to their ability to control cell repulsion, ephrin and Eph receptors play a major role in the penetration of tissue by cancer cells and in the formation of metastases. For this reason, receptors and their connection partners are the focus of current medical research. Better understanding of this signalling pathway, through which cell repulsion is controlled, could enable the development of new drugs to combat cancer.

###

Original publication: Thomas N. Gaitanos, Jorg Koerner, Rüdiger Klein
Tiam/Rac signaling mediates trans-endocytosis of ephrin receptor EphB2 and is important for cell repulsion.
Journal of Cell Biology; 5 September, 2016

Media Contact

Dr. Stefanie Merker
merker@neuro.mpg.de
49-898-578-3514

 @maxplanckpress

http://www.mpg.de 

Dr. Stefanie Merker | EurekAlert!

More articles from Life Sciences:

nachricht Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>