MAPT and early-onset autosomal dominant Alzheimer disease: However, aberrant phosphorylation attenuates the bindingaffinity of tau to a microtubule (MT), resulting in MT destabilizationfollowed by accumulation of neurofibrillary tangles in the brain.There are in total 85 potential phosphorylation sites in a full-lengthtau protein, and about half of them are abnormal as they occur intau of Alzheimer’s disease (AD) brain only.