Two of the main features found in the brains of people with of Alzheimer's disease, are neurobrillary tangles ('tangles' for short), which are made up of a protein called tau, and senile plaques (which are made mostly from another protein called beta-amyloid, they are also sometimes called beta-amyloid bundles or 'bundles' for short). The tau proteins that form the tangles previously held together a structure inside the neurons called a microtubule which is an important part of the neuron; it forms part of the cytoskeleton (cell skeleton) which is what maintains a cell's shape, and microtubules plays a part in cell communication.[3]
Both tangles and plaques may be caused by other diseases, such as Herpes simplex virus Type 1 which is being investigated as a possible cause or contributor in developing Alzheimer's. It is not known for sure if tangles and plaques are part of what causes Alzheimer's, or if they are the results.
Microtubules Kinesin cartoon.png
Microtubules are made of a protein called tubulin. The tubulin is polymerized, which is when molecules form the same shapes over and over again that are linked together in groups, and these groups are linked together. They can form long chains or other shapes; in this case the polymerized tubulin forms microtubules. The microtubules are rigid tubes like microscopic straws which are hollow inside. Microtubules help keep the shape of the neuron, and are inolved in passing signals through the neuron.[4]