Tau protein in Alzheimer's disease, illustration. The insets show two ways in which pathological phosphorylation (yellow) of Tau proteins (red-orange) by kinases (blue-purple) affect nerve cells in what is called a neurofibrillary tangle. The main illustration showing a nerve cell (neuron, blue, lower left) and its axon (across bottom), shown in a misshapen and abnormal state. Pathological aggregations of tau proteins cause disintegration of microtubules (inset at left). The transport of synaptic vesicles (orange-blue spheres, inset at right) is also interrupted. A neurofibrillary tangle consists of abnormal aggregates and insoluble fibres of the protein tau. Tau protein is an abundant neural protein, aggregations of which are thought to play a role in Alzheimer's disease and other neural disorders.