The role of PP2A in eEF2 phosphorylation. (A) Activity of PP2A in SKBR3-par and SKBR3-L cells, untreated and treated with 5 nM OA for 24 hr. (B) Immunoblot examining the effect of OA alone and in combination with lapatinib on levels of total and phosphorylated eEF2(Thr56) and AKT(Ser473). (C) Effect of 5 nM okadaic acid (OA) on growth of SKBR3-par and SKBR3-L cells. (D) Effect of OA alone and in combination with lapatinib on the growth of SKBR3-par cells and (E) SKBR3-L cells. Error bars represent the mean ± SD (n = 3). *denotes p ≤ 0.05, **denotes p ≤ 0.01.