Which protein forms senile plaques and is considered a significant biomarker of Alzheimer's?

Amyloid-beta is a key protein involved in the formation of senile plaques, which are one of the hallmark features of Alzheimer's disease. These plaques accumulate in the brains of individuals with Alzheimer's and are believed to disrupt cell communication and trigger inflammatory responses that ultimately lead to neuronal death. The presence of amyloid-beta in the brain is thus considered a significant biomarker for the disease, as its levels are correlated with the progression of Alzheimer’s.

In contrast, dopamine is primarily associated with mood regulation and movement, and while it is essential for brain function, it does not have a direct link to the pathology of Alzheimer's. Neurotrophin refers to a family of proteins that support the growth and survival of neurons, contributing to their health but not specifically to Alzheimer's disease pathology. Beta-amyloid precursor protein does play a role in the production of amyloid-beta, but it is the amyloid-beta itself that serves as the significant biomarker and is directly implicated in plaque formation. Thus, amyloid-beta is the critical protein in this context.