Final answer:
Prion proteins cause neurological diseases by misfolding and triggering other normal proteins to misfold, forming plaques and leading to brain cell death. This process results in debilitating diseases like Creutzfeldt-Jakob disease and mad cow disease, with symptoms that worsen over time until they result in death.
Step-by-step explanation:
How Prion Proteins Cause Neurological Diseases
Prion proteins cause neurological diseases when they misfold into a pathogenic form known as PrPSC. Normally present in a healthy brain as PrPC, prions can misfold due to genetic mutations or spontaneously. Misfolded prions are infectious and can convert normal prion proteins into the misfolded state. This causes an accumulation of the abnormal protein, leading to the formation of fibrils and plaques within nerve cells that result in cell death.
Diseases such as Creutzfeldt-Jakob disease, mad cow disease (BSE), and other transmissible spongiform encephalopathies (TSEs) occur due to the buildup of these proteins in the brain. The brain tissue takes on a sponge-like appearance, with resultant symptoms including memory loss, personality changes, uncoordinated movements, and ultimately leading to coma and death.
While prions are also associated with Alzheimer's Disease, their role is somewhat indirect, as Alzheimer's is primarily linked to the accumulation of beta-amyloid plaques. Similarly, Parkinson's disease involves an increase in alpha-synuclein protein, though the exact relationship to prions in these conditions is still being elucidated.