?-amyloid induced hyperphosphorylation of tau in human neuroblastoma cells involves map kinase

Treatment of retinoic acid-differentiated SH-SY-5Y human neuroblastoma cells with a sublethal concentration (22μM) β-amyloid (βA) in the presence of 1.8mM extracellular calcium induced a marked increase in PHF-1 immunoreactivity. The βA-induced increase in PHF-1 immunoreactivity was prevented by the MAP kinase kinase inhibitor PD 89059. These data indicate that βA-induced tau hyperphosphorylation is mediated via activation of the MAP kinase pathway.