GSK3B and Alzheimer disease: PDC was further shown to be phosphorylated by the Ser/Thr kinase TPKI/GSK-3β (Tau protein kinase I/glycogen synthase kinase 3β) [147], which was originally identified as a tau-kinase associated with brain microtubules, possibly involved in phosphorylation of the Tau protein that occurs in Alzheimer’s disease [148]; this kinase is presently known to play a key role in the molecular pathophysiology of many neurodegenerative diseases [12].