MAPK4 up-regulates PDK1 protein expression in cancer cells.

Western blots on (A) engineered SUM159, MDA-MB-436, MDA-MB-468, HCC1395, and HCC1806 cells with 0.5 μg/ml Dox-induced ectopic expression of MAPK4 (iMAPK4) or control (iCtrl), (B) engineered HS578T, SUM159, and HCC1937 cells with 4 μg/ml Dox-induced knockdown of MAPK4 (iG2 and iG4) or control (iNT), (C) the parental vs. MAPK4-KO MDA-MB-231 cells (clone# 2, 3) and SUM159 cells (clone# 1, 2), and (D) the parental vs. MAPK4-KO MDA-MB-231 (clone# 3) and SUM159 cells (clone# 2, KO cells) vs. MAPK4-KO cells with rescued 0.5 μg/ml Dox-induced MAPK4 expression (KO+iMAPK4). All cells in Panel D were treated with 0.5 μg/ml Dox. Data are representative of at least 2–3 independent experiments. MAPK4, mitogen-activated protein kinase 4; PDK1, phosphoinositide-dependent kinase-1.