β-Carboline Compounds, Including Harmine, Inhibit DYRK1A and Tau Phosphorylation at Multiple Alzheimer's Disease-Related Sites
Figure 5
Harmine inhibits the DYRK1A catalyzed direct phosphorylation of tau protein on serine 396.
Shown in (A) are results of an in vitro phosphorylation assay utilizing recombinant DYRK1A and tau proteins. A doublet pS396 tau phosphorylation is observed only in the presence of tau, DYRK1A, and ATP. In (B), harmine potently inhibits the direct phosphorylation of tau protein by DYRK1A with an IC50 of 0.7 µM.