MAPT and Parkinson disease: Further ex vivo and in vitro examinations revealed an even larger number of cross-interacting pairings, which include amyloid-beta with Tau [12,13] (related to AD), prion proteins [14] (prionopathies), and alpha-synuclein (PD) [15], as well as alpha-synuclein with Tau [16,17] and prion proteins [18].