MAPT and tauopathy: The core of the paired helical filament is composed of a truncated 95-amino-acid fragment of tau (Wischik et al., 1988) and is capable of catalytic conversion of normal soluble tau into intracellular oligomeric aggregates (Wischik et al., 1995, 1996), resulting in dystrophic neurites, dendrites and cell bodies, a characteristic pathology of tauopathies (Spires-Jones et al., 2009).