Laminin builds the neuromuscular synapse

Sep 15, 2008

Like a plug and a socket, a nerve and a muscle fiber mesh at the neuromuscular junction. New work by Nishimune et al published in the Journal of Cell Biology reveals that an extracellular matrix protein called laminin shapes both sides of the junction to ensure they fit together.

A neuromuscular junction, or synapse, in a newborn mouse is functional but simple, with a globular nerve terminal meeting a flat, oval structure on the muscle fiber. As the animal matures, the nerve terminal branches into a claw shape, and the muscle side contorts into a matching conformation. But what coordinates these changes so the two sides mirror each other? The researchers think that one molecule in the synapse sculpts both sides.

Their chief suspect was the synapse-spanning protein laminin. Made by muscle and forming part of the sheath that covers muscle, the laminin protein has different domains called alpha, beta, and gamma chains. Previous work had shown that the beta2 chain of laminin spurs differentiation of the nerve terminal. The team has now found evidence that the alpha chains of laminin influence post-synaptic patterning. For example, maturation of the muscle side slowed in mice lacking the alpha5 chain of laminin in their muscles.

The researchers discovered that cell surface receptor molecules that recognize and bind laminin, are corralled by laminin on the muscle side of the synapse. These receptors, in turn, gather other receptors that respond to signals from the nerve. Overall, the work suggests that the beta and alpha chains of laminin together influence pre-synaptic and post-synaptic development, thus providing a way to coordinate maturation of the sending and receiving sides of the synapse.

Citation: Nishimune, H., et al. 2008. J. Cell Biol. doi:10.1083/jcb.200805095.

Source: Rockefeller University

Explore further: Researcher reveals how amphibians crossed continents

add to favorites email to friend print save as pdf

Related Stories

Social Security spent $300M on 'IT boondoggle'

2 hours ago

(AP)—Six years ago the Social Security Administration embarked on an aggressive plan to replace outdated computer systems overwhelmed by a growing flood of disability claims.

Cheaper wireless plans cut into AT&T 2Q profit

2 hours ago

(AP)—AT&T posted lower net income for the latest quarter due to cheaper cellphone plans it introduced as a response to aggressive pricing from smaller competitor T-Mobile US.

Awarded a Pell Grant? Better double-check

2 hours ago

(AP)—Potentially tens of thousands of students awarded a Pell Grant or other need-based federal aid for the coming school year could find it taken away because of a mistake in filling out the form.

Recommended for you

'Killer sperm' prevents mating between worm species

4 hours ago

The classic definition of a biological species is the ability to breed within its group, and the inability to breed outside it. For instance, breeding a horse and a donkey may result in a live mule offspring, ...

Rare Sri Lankan leopards born in French zoo

7 hours ago

Two rare Sri Lankan leopard cubs have been born in a zoo in northern France, a boost for a sub-species that numbers only about 700 in the wild, the head of the facility said Tuesday.

Japan wraps up Pacific whale hunt

8 hours ago

Japan announced Tuesday that it had wrapped up a whale hunt in the Pacific, the second campaign since the UN's top court ordered Tokyo to halt a separate slaughter in the Antarctic.

Researchers uncover secrets of internal cell fine-tuning

8 hours ago

New research from scientists at the University of Kent has shown for the first time how the structures inside cells are regulated – a breakthrough that could have a major impact on cancer therapy development.

User comments : 0