Understanding how cell semaphorins and plexins interact

Oct 20, 2010
Structures of two semaphorin-plexin complexes reveal that a common mode of interaction underlies semaphorin-plexin cell-cell signalling.

Axons are the communication channels of the body. Up to a metre in length, they connect parts of the body to the brain, carrying signals from muscles, organs and tissues. As the central nervous system develops these axons must follow very precise paths through the body. The route that they take is guided by proteins, which signal paths that the axon should and shouldn’t take. A group of proteins called semaphorins are known to be responsible for directing axons away from inappropriate areas.

However in recent years there has been increasing evidence that semaphorins and their receptors, plexins, also play a role in a number of processes including the progression of cancer. Scientists from the University of Oxford have been studying how semaphorins and plexins interact to understand how cells send signals to each other.

This research has been published in the journal Nature.

Semaphorin-plexin signalling has received a lot of attention over the last decade, for the role it plays in neural connectivity, cancer and immune response. However until now there has not been any structural information on the extracellular parts of the plexin, so the mechanism of semaphorin interaction hasn’t been resolved. The group from the University of Oxford have been using I03, one of the Macromolecular Crystallography beamlines at Diamond to determine the structure of the semaphorin-binding regions of plexins and understand the mechanism on the molecular scale.

The group found that semaphorin dimers independently bind two plexin molecules, and the signalling ability of the resulting complex depends on the strength of the combined bonds – monomeric semaphorin can bind to plexin but doesn’t result in signalling.

“The data we collected at Diamond have allowed us view in atomic level detail the triggering of the signals that help wire up our nervous system," said Professor Yvonne Jones, University of Oxford.

Explore further: Potential therapy for the Sudan strain of Ebola could help contain some future outbreaks

More information: Structural basis of semaphorin–plexin signalling, Bert J. C. Janssen, et al. Nature, Sept 2010 DOI: 10.1038/nature09468

Provided by Diamond Light Source

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Prostate cancer spurs new nerves

Dec 01, 2008

Prostate cancer – and perhaps other cancers – promotes the growth of new nerves and the branching axons that carry their messages, a finding associated with more aggressive tumors, said researchers from Baylor College ...

Scientists discover a controller of brain circuitry

Dec 28, 2009

By combining a research technique that dates back 136 years with modern molecular genetics, a Johns Hopkins neuroscientist has been able to see how a mammal's brain shrewdly revisits and reuses the same molecular ...

EphA4 -- the molecular transformer

Oct 23, 2009

(PhysOrg.com) -- EphA4 is a protein which is attached to the surfaces of many types of human cells and plays a role in a wide range of biological processes. EphA4 functions by binding to ephrin ligands, cell ...

Recommended for you

Breaking benzene

16 hours ago

Aromatic compounds are found widely in natural resources such as petroleum and biomass, and breaking the carbon-carbon bonds in these compounds plays an important role in the production of fuels and valuable ...

How to prevent organic food fraud

18 hours ago

A growing number of consumers are willing to pay a premium for fruits, vegetables and other foods labelled "organic", but whether they're getting what the label claims is another matter. Now scientists studying ...

User comments : 0