Research: Stable insulation

7 January 2008

Researchers identify a protein that helps to stabilise the myelin sheath surrounding nerve cells.

A molecule called JAM-C appeared to have a well-defined role in blood vessels and the digestive system, helping the interaction of neighbouring cells or of immune cells during inflammation. But JAM-C has now been found in an unexpected location: the myelin sheath, which helps to isolate nerve cells electrically from their surroundings and allows nerve bundles to transmit impulses overlong distances.

Sussan Nourshargh (Barts and The London School of Medicine, London), colleagues and collaborators found JAM-C in myelin-producing cells of the peripheral nervous system, at junctions between adjacent myelin folds. They also found that mice lacking the gene for JAM-C had defects in the structure of their myelinated nerves. This suggests that, as in blood vessels, JAM-C in nerves helps to maintain strong junctions between neighbouring structures and so is important for the integrity of nerves.

The absence of JAM-C in mice also led to a reduced rate of impulse conduction in the nerve bundles, and caused muscle weakness - symptoms similar to those of some human hereditary neuropathies.

References

Scheiermann C et al. Expression and function of junctional adhesion molecule-C in myelinated peripheral nerves. Science 2007;318(5855):1472-5.