Abstract
In this article I shall review how tau phosphorylation and aggregation participates in Alzheimer's disease (AD) and other tauopathies. Tau, a microtubule associated protein, is the main component, in phosphorylated form, of the aberrant paired helical filaments found in AD. Tau is present in phosphorylated and aggregated form not only in AD, but in other pathologies (tauopathies). In this review, the phosphorylation of tau, its aggregation, and the possible relation between tau phosphorylation and aggregation is, briefly, described. Also, it is discussed the toxicity of modified tau. In addition, I propose a working model detailing the progression of tau pathologies.