Tau and amyloid beta are implicated in the mechanisms of Alzheimer's disease; here researchers look into why we see both: "two kinds of abnormal structures accumulate in the brain: amyloid plaques and neurofibrillary tangles. The plaques contain fibrils that are made from protein fragments called 'beta-amyloid peptides.' The tangles also are fibrous, but they are made from a different substance, a protein called 'tau.' ... researchers found a deadly connection between beta-amyloid and tau, one that occurs before they form plaques and tangle ... We think we've found one of the seminal cell biological events in the pathogenesis of Alzheimer's and if we can figure out all of the steps in the process and understand each player at every step, it will represent many potential new drug targets for Alzheimer's therapy. Our paper defines one of the earliest events that causes neurons to die in both early-onset familial Alzheimer's and late-onset Alzheimer's disease. We believe this is the first evidence for the long elusive 'missing link' between amyloid and tau in Alzheimer’s disease."