Muscle weakness: New mutation identified

Jun 14, 2007

New research, published in The Journal of Physiology, has identified a novel mutation associated with muscle weakness and distal limb deformities. The study demonstrates that muscle weakness experienced by persons with a regulatory protein tropomyosin mutation is directly related to a mechanism by which the mutant tropomyosin modulates contractile speed and force-generation capacity.

Dr. Julien Ochala and co-workers at the Department of Clinical Neurophysiology, University of Uppsala, in collaboration with scientists at the Department of Pathology, University of Göteborg, explored the mechanisms underlying the muscle weakness experienced by a woman and her daughter with a β-tropomyosin mutation, i.e., muscle weakness in the absence of macro or microscopic signs of muscle wasting.

The results from single fibre contractile measurements and in vitro motility analyses demonstrated a mechanism where tropomyosin modulates myosin-actin kinetics. A slower motor protein myosin attachment rate to and a faster detachment rate from actin, caused by the mutation, results in a reduced number of myosin molecules in the strong actin binding state and muscle weakness. The results also implicate a potential role of the regulatory protein tropomyosin in modulating contractile speed and force-generation under physiological conditions.

It is suggested that the findings at the gene, protein and muscle cell levels in this specific neuromuscular disorder will have a significant impact on our understanding of the disease pathogenesis and provide important information for future therapeutic strategies. Walter R. Frontera, an independent expert, says: "Dr. Ochala and collaborators have published elegant proof of the clinical consequences of mutations in the regulatory proteins of skeletal muscles. Their data provide strong support for the dissociation between qualitative alterations in muscle contractility and quantitative evidence of muscle atrophy".

Source: Blackwell Publishing Ltd.

Explore further: Technique to model infections shows why live vaccines may be most effective

add to favorites email to friend print save as pdf

Related Stories

Peugeot hybrid compressed-air car set for Paris Motor Show

1 hour ago

An 860-kilogram concept city car from Peugeot indicates impressive fuel economy. This latest concept "has its sights set on meeting the French government's goal of putting an affordable 2.0l/100km (141mpg) car into production by 2020," said Jordan Bis ...

Recommended for you

New molecule allows for increase in stem cell transplants

23 minutes ago

Investigators from the Institute for Research in Immunology and Cancer (IRIC) at the Université de Montréal have just published, in the prestigious magazine Science, the announcement of the discovery of a new molecule, the fi ...

Team explores STXBP5 gene and its role in blood clotting

2 hours ago

Two independent groups of researchers led by Sidney (Wally) Whiteheart, PhD, of the University of Kentucky, and Charles Lowenstein, MD, of the University of Rochester, have published important studies exploring the role that ...

User comments : 0