LONDON, 7 September (SPIS MedWire). A key protein involved in the degeneration of nerve cells in Alzheimer's disease has been isolated (Nature 2000, 407:48-54). The previously unknown protein seems to be involved in the biochemical processing of the β-amyloid precursor peptide, which forms toxic 'plaques' in the brain tissue of Alzheimer's sufferers. Peter St George-Hyslop and his team at the University of Toronto isolated the protein - nicastrin - while looking for new proteins that bind to presenilin proteins, because mutations in these proteins can cause the accumulation of the toxic β-amyloid peptide. Nicastrin seems to bind to the β-amyloid precursor protein and regulate the production of the potentially dangerous β-amyloid peptide fragment. Dr St George-Hyslop, Director of the Center for Research in Neurodegenerative Diseases, said: "We discovered a way to manipulate nicastrin to either increase or decrease the production of the harmful amyloid β-peptide. This could lead to new treatments that will target nicastrin to prevent the overproduction of this neurotoxic protein."