Localization of the mitogen activated protein kinase ERK2 in Alzheimer's disease neurofibrillary tangles and senile plaque neurites.

The phosphorylation of normal tau by mitogen activated protein (MAP) or extracellular signal related kinases (ERKs) induces tau to acquire biochemical properties of Alzheimer's disease (AD) paired helical filament (PHF) proteins in vitro. We show here that a monoclonal antibody to MAP kinases recognizes ERK2 in normal and AD cortex, but ERK2 levels are slightly reduced in the AD brain. Since ERK2 was detected in neurofibrillary tangles and senile plaque neurites in the AD hippocampus, ERK2 is positioned to phosphorylate normal tau and could play a role in the generation of PHFs in AD.