FIGURE 4.
mNLS-I2PP2A promotes abnormal hyperphosphorylation of Tau in Tau441-Tet-Off-mNLS-I2PP2A PC12 cells, an inducible cell model. A, cells were treated with or without Dox (1 μg/ml) for 72 h, and the cell lysates were used to measure Tau phosphorylation by Western blots developed with 12E8 (Ser(P)262/Ser(P)356) and PHF1 (Ser(P)396/Ser(P)404) Tau antibodies. B, quantitative analysis showing the suppression of the expressions of I2PP2AWT and I2PP2AAA-AAA with Dox. C, quantitative analysis showing Tau hyperphosphorylation at 12E8 and PHF1 sites expressed as mean ± S.E. (error bars) after normalization with total Tau (43D). The abnormal hyperphosphorylation of Tau at 12E8 and PHF1 sites seen in a Dox-dependent manner was higher in I2PP2AAA-AAA than in I2PP2AWT cells due to the cytoplasmic localization of the former. *, p < 0.05; **, p < 0.01.