Microtubule-associated protein tau (tau protein) promotes microtubule assembly and stability, and is involved in the establishment and maintenance of neuronal polarity. The C-terminus binds a, Xenopus/Amphibian,onal microtubules while the N-terminus binds neural plasma membrane components, suggesting that tau functions as a linker protein between both. A, Xenopus/Amphibian,onal polarity is predetermined by tau localization in the domain of the cell body defined by the centrosome. The short isoforms allow plasticity of the cytoskeleton whereas the longer isoforms preferentially play a role in its stabilization. Hyperphosphorylation of the tau protein (tau inclusions,PorcineTau) can result in the self-assembly of tangles of paired helical filaments and straight filaments, which are involved in the pathogenesis of Alzheimer's disease and other tauopathies.