A protein that helps worm sperm to fertilise an egg may be related to a human protein that plays a role in inherited forms of amyotrophic lateral sclerosis (ALS).

ALS, often called Lou Gehrig’s disease in the US, paralyses muscle cells that control movement. There is no cure or treatment, and no conclusive evidence of what causes it. Those with the condition almost always die within a few years.

The new discovery, by Michael Miller at the University of Alabama in Birmingham and colleagues at Baylor College of Medicine in Houston, Texas, has highlighted a protein that may be a culprit. The protein, called MSP, was first found in male Caenorhabditis elegans nematode worms 11 years ago. It is secreted by sperm cells to prepare eggs for fertilisation.

In 2004, a similar protein was discovered in a large human family with the inherited form of ALS. In humans it appears to be involved in signalling between cells, especially muscle cells.


Miller’s team has now found that if worms and fruit flies have a mutation that makes them produce less MSP, they suffer mitochondrial defects like those in people with ALS. This suggests that a lack of the protein might help trigger the disease. Every person with ALS studied so far also has less of the protein than healthy people, adds Miller.

“The science is certainly interesting,” says Jeffrey Rothstein, director of the Robert Packard Center for the Study of ALS at Johns Hopkins University in Baltimore, Maryland. “But I don’t know that there is a therapy in there somewhere.” He says that although the protein may be involved in inherited forms of ALS, it is not yet clear that it is also relevant to the more common non-familial forms of the condition.

Journal reference: Developmental Cell, DOI: 10.1016/j.devcel.2011.12.009