Clinical Significance

The microtubule system is a component of the neural cytoskeleton and can be involved in a variety of cellular functions. Microtubules are composed of microtubule proteins and microtubule-associated proteins, and Tau protein is the most abundant microtubule-associated protein. The cellular functions of Tau protein in normal brain are to bind to microtubule proteins to promote their polymerization to form microtubules, to bind to formed microtubules to maintain microtubule stability, to reduce dissociation of microtubule protein molecules, and to induce microtubule bundling.

The Tau protein gene is located on the long arm of chromosome 17. Tau protein is a phosphate group-containing protein, and the normal mature brain contains two to three phosphate groups in the Tau protein molecule. In contrast, Tau proteins in the brain of Alzheimer's patients are abnormally hyperphosphorylated and can contain 5 to 9 phosphate groups per molecule of Tau protein, with loss of normal biological function.