Figure 7.

Knockdown ${\text{I}}_2^{\text{PP2A}}$ phosphorylates GSK-3β at Ser9 and inhibits GSK-3β activity. HEK293/tau or N2a/tau cells were transfected with ${\text{pSUP - siI}}_2^{\text{PP2A}}$ (pSUP-siI₂) for 24 h, and pSUP and pSUP-siC were transfected as the controls. (A,C) The protein levels of total (tGSK-3β) and the Ser9-phosphorylated GSK-3β (pS9, the inactive form) were estimated by Western blotting normalized against DM1A. (B) The mRNA level of GSK-3β was analyzed by real-time PCR, normalized against GADPH and expressed by setting pSUP as 1. The data were presented as mean ± SD of three independent experiments. *p < 0.05; **p < 0.01 vs. pSUP.