Faulty regulation of tau phosphorylation by the reelin signal transduction pathway is a potential mechanism of pathogenesis and therapeutic target in Alzheimer's disease.

Hyperphosphorylated tau protein is the basic structural component of the neurofibrillary tangle, a histopathological hallmark of Alzheimer's disease. The formation of hyperphosphorylated tau protein may impair learning and the synaptic plasticity of neurons. Tau is a protein that is associated with and stabilizes microtubules; hyperphosphorylated tau protein is unable to perform this stabilization function. The transduction of reelin, a protein that is crucial to neuronal migration and the formation of synaptic connections in the fetal brain, may have an equally important role in regulating at least some forms of learning and synaptic plasticity in the fully developed mature brain. Reelin transduction is mediated by receptors in the brain that are members of the superfamily of low-density lipoprotein receptors. An important downstream target of reelin signal transduction appears to be inhibition of an enzyme involved in the regulation of tau phosphorylation. The faulty transduction of the reelin signal may be a pathological mechanism leading to hyperphosphorylation of tau protein. Ultimately, inhibition of tau phosphorylation may be an important therapeutic target in Alzheimer's disease and other neuropsychiatric disorders.