Claudin 11 stops the leaks in neuronal myelin sheaths

Dec 01, 2008

Devaux and Gow demonstrate how a tight junction protein called claudin 11 makes the neuronal myelin sheath a snug fit. The study will be published in the December 1, 2008 issue of the Journal of Cell Biology.

Like the rubber coating on a copper wire, the myelin sheath—a membrane extension of glial cells that spirals around the axons of neurons—creates an insulation layer that prevents current leakage from axons and aids electrical conduction along the length of the axon.

Claudin 11 forms tight junctions between successive spiral layers of the myelin sheath, but it was unknown whether it was required for myelin to act as a good insulator. To examine this question, Devaux and Gow compared electrical recordings from the optic nerve of wild-type and claudin 11 knockout mice. They found that although claudin 11 deficiency caused no gross defects in the appearance of the myelin sheath, it slowed electrical signals—at least in neurons with small-diameter axons.

Using a computer model that incorporates the resistive and capacitive properties of axons (and their myelin sheaths), the authors showed that claudin 11 adds to the electrical resistance of myelin by preventing leakage of charged ions (and electrical current) through the spiral space between myelin layers. The reduced resistance in the absence of claudin 11 affects small-diameter axons most severely because such axons have thinner myelin sheaths and thus less insulation to begin with. Because neurons with small-diameter axons are mostly found in the CNS, the authors speculate that defects in claudin 11 could be associated with deficits in cognition and perception, like those found in schizophrenia or neurodegenerative diseases.

Citation: Devaux, J., and A. Gow. 2008. J. Cell Biol. doi:10.1083/jcb.200808034. (www.jcb.org)

Source: Rockefeller University

Explore further: Monarch butterflies plummet 90 percent, need protection

add to favorites email to friend print save as pdf

Related Stories

Water crisis threatens thirsty Sao Paulo

2 hours ago

Sao Paulo is thirsty. A severe drought is hitting Brazil's largest city and thriving economic capital with no end in sight, threatening the municipal water supply to millions of people.

Canada to push Arctic claim in Europe

3 hours ago

Canada's top diplomat will discuss the Arctic with his Scandinavian counterparts in Denmark and Norway next week, it was announced Thursday, a trip that will raise suspicions in Russia.

Google to help boost Greece's tourism industry

3 hours ago

Internet giant Google will offer management courses to 3,000 tourism businesses on the island of Crete as part of an initiative to promote the sector in Greece, industry union Sete said on Thursday.

NKorea launch pad expansion 'nearing completion'

3 hours ago

A U.S. research institute says construction to upgrade North Korea's main rocket launch pad should be completed by fall, allowing Pyongyang (pyuhng-yahng) to conduct a launch by year's end if it decides to do so.

Recommended for you

Walking fish reveal how our ancestors evolved onto land

23 minutes ago

About 400 million years ago a group of fish began exploring land and evolved into tetrapods – today's amphibians, reptiles, birds, and mammals. But just how these ancient fish used their fishy bodies and ...

The roots of human altruism

2 hours ago

Scientists have long been searching for the factor that determines why humans often behave so selflessly. It was known that humans share this tendency with species of small Latin American primates of the ...

User comments : 0