MAPT and neurodegenerative disease: ROS can affect factors related to the pathobiology of neurodegenerative diseases such as hyperphosphorylation of tau and misfolding of amyloid beta (which are key components of intracellular neurofibrillary tangles (NFTs) and extracellular amyloid plaques), alpha-synuclein (present in Lewy bodies), and mutant Huntington protein.