Fig. 5

Ser24-PP2Ac phosphorylation regulates the PP2A switch through binding to PI3K and AKT but not IGBP1. A, B Ser24-PP2Ac phosphorylation regulates the PP2A switch related phosphorylation on AKT and PI3K inactivation. αT3-1 (A) or PC3 (B) cells were transfected with either HA-PP2Ac or PP2Ac mutants (S24A, S24E) in PCDNA3 in serum starvation medium (0.1% FCS 16 h). The cells were then either stimulated with TPA (250 nM, 30 min) or left untreated, harvested and analyzed using Western blot with the indicated Abs. The bar-graphs represent means ± SD of three experiments. Significance of change from non-stimulated control (time 0) is calculated. * p < 0.01, ** p < 0.05. C, D Ser24-PP2Ac phosphorylation regulates binding of PP2Ac to AKT and PI3K. αT3-1 (C) or PC3 (BD) cells were treated as described in panels A, B and PP2Ac was IPed using Ab against the HA tag. The CoIPed proteins were analyzed using the indicated Abs. IgG was used as a CoIP negative control. The bar-graphs represent means ± SD of three experiments. Significance of change from non-stimulated control (time 0) is calculated. * p < 0.01, ** p < 0.05