MAPT, also known as TAU, is a neuronal microtubule associated protein found predominantly on axons. The function of this protein is to promote tubulin polymerisation and stabilise microtubules, but it also serves to link certain signalling pathways to the cytoskeleton. MAPT, in its hyperphosphorylated form, is the major component of paired helical filaments (PHF) and neurofibrillary lesions in Alzheimer's disease (AD) brain.