18 Dec 1997

A pathologic form of prion protein is believed to cause scrapie, bovine spongiform encephalopathy and Creutzfeldt-Jakob disease. The normal function of prion protein is yet unknown, but a recent study by Hans Kretzschmar of the University of Gottingen, Germany, and colleagues finds that the structure of the protein lends itself to binding copper with high affinity. Knockout mice lacking the prion-protein gene have a deficiency of copper in the cell membranes extracted from brain tissue. The results suggest that the normal function of protein is in the transport or storage of copper. Intriguingly, proteins such as monoamine oxidase, amyloid precursor protein and superoxide dismutase-1 (SOD-1)-implicated in a variety of neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and familial amyotrophic lateral sclerosis-are all copper-binding metalloproteins. The common denominator of copper suggests that neurons are specially sensitive to copper, and possess special mechanisms to regulate its distribution.—June Kinoshita