MAPT and Alzheimer disease: neurons which are not able to undergo re-differentiation will die via an apoptotic pathway or produce AD pathology such as tau hyperphosphorylation and Aβ deposition that ultimately leads to neuronal cell death [43].In addition to cyclin B, the expression of PLKs (Drosophila polo homologues) is upregulated in susceptible hippocampal and cortical neurons of AD patients [44, 45].