What type of protein is known to stabilize the cellular skeleton but forms neurofibrillary tangles in Alzheimer's patients?

The tau protein plays a crucial role in stabilizing microtubules, which are important components of the cellular cytoskeleton in neurons. These microtubules are essential for maintaining the structure of the neuronal cell and facilitating the transport of various substances along the axons. In a healthy brain, tau helps to promote the stability and integrity of these microtubules.

However, in the context of Alzheimer's disease, tau protein becomes hyperphosphorylated. This abnormal phosphorylation leads to the misfolding and aggregation of tau, resulting in the formation of neurofibrillary tangles within neurons. These tangles disrupt the normal function of the cell and are one of the key pathological features observed in the brains of individuals with Alzheimer's disease. The presence of neurofibrillary tangles is associated with the progression of cognitive decline in affected patients.

Therefore, the tau protein is specifically linked to both the stabilization of the cellular skeleton under normal conditions and to the formation of neurofibrillary tangles in the context of Alzheimer's disease.