MAPT and Alzheimer disease: We previously showed that the recombinant CDK2/CycA3 complex generates robust and reproducible phosphorylation of Tau at AD-specific epitopes, with high levels of phosphate incorporation at pS202-pT205 and pT231-pS235 ([30]; Fig. S1), recognized respectively by the diagnostic AT8 [1] and AT180 [2] AD-specific monoclonal antibodies.