Fig. 1

Pyk2 phosphorylates Tau via GSK3β in a Hek293T over-expression system. Hek293T cells were transfected with combinations of the proteins indicated, and lysates separated via SDS-PAGE. Separated lysates were immunoblotted with the antibodies listed. A, Representative immunoblot images of transfected Hek293T cells. B and C, Quantification of A. Over-expression of Pyk2 led to a significant increase in the activity of over-expressed GSK3β (pGSK3β Y216 normalized to total GSK3β). This increase was further augmented by the co-transfection of Fyn with GSK3β and Pyk2 (B). The phosphorylation of over-expressed Tau at S202/T205 (AT8) normalized to total Tau (HT7) was significantly increased when co-transfected with GSK3β and Pyk2, but not when co-transfected with either kinase alone. No further increase in normalized AT8 signal was observed when Tau, Pyk2 and GSK3β were co-transfected with Fyn. Data are graphed as mean ± SEM, one-way ANOVA with Tukey’s multiple comparisons test, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, n = 3