Neurodegeneration Appears Tied
To Molecular Motor Breakdowns

Findings from a multinational group coordinated by biologist Laura Ranum at the University of Minnesota add support for the involvement of cellular transport defects in neurodegeneration. Amyotrophic lateral sclerosis (ALS), like Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and many others, is a neurodegenerative disorder.

Ranum, who has had MDA funding for research in myotonic dystrophy, has been studying a disease called spinocerebellar ataxia type 5, a neurodegenerative condition linked to chromosome 11.

Her group has now identified mutations in the gene for the beta-3 spectrin protein in three large families as the cause of their SCA5. An American, French and German family were each found to have different spectrin mutations.

Spectrin proteins are part of the cellular transport apparatus so recently implicated as a problem in the wobbler mouse.

A spectrin molecule, along with several others, forms a multiprotein molecular motor that attaches transport vesicles and their cargo to the microtubules, and moves them along these highways.

“We’re thrilled to have found this gene,” Ranum said. “I think that there could be broader implications, for ALS and other neurodegenerative disorders,” she added, citing known deficits in transport that occur in Huntington’s and Alzheimer’s disease.