Structure of a microtubule, illustration - stock illustration

Structure of a microtubule, 3D computer illustration. Microtubules are polymers of the protein tubulin which is composed of two subunits, alpha- and beta-tubulin. They are a component of the cytoskeleton, which maintains a cells shape, allows some cellular mobility and is involved in intracellular transport. The tubular polymers of tubulin can grow as long 50 micrometres and are highly dynamic. In Alzheimers disease, the transport of tau-protein (belonging to the MAP proteins) stabilizing the microtubules is disturbed and allows phosphate-groups to attach to the tau-protein, destabilizing the microtubuli of brain axons. This leads to the agglutination of the nerve cells resulting in neuronal degeneration.