Kinase activities of bone morphogenetic protein (BMP) type I receptor and erythropoietin‐producing hepatocellular carcinoma receptor A6 (EPHA6) are differentially required in apoptosis induction. A, Immunoblot analysis of TGS‐03 and TGS‐04 cells infected with ad‐LacZ, ad‐EPHA6‐WT or adenovirus with kinase‐dead EPHA6 K757R (ad‐EPHA6‐KD) and stimulated with or without BMP‐2 for 2 d as indicated. pEPHA, phospho‐EPHA; p‐p38, phospho‐p38; pSMAD1/5, phospho‐SMAD1/5. B, C, Quantification of apoptosis of TGS‐03 (B) and TGS‐04 (C) cells infected with ad‐LacZ, ad‐EPHA6‐WT and ad‐EPHA6‐KD, stimulated with or without BMP‐2 for 5 d with FACS analysis. Graphs represent mean values from two independent experiments. D, FACS diagrams of TGS‐04 cells infected with ad‐LacZ or ad‐EPHA6‐WT with or without 1 μmol/L LDN193189 and BMP‐2 for 6 d. Percentages represent apoptotic cells. Y‐axis plots propidium iodide signal and X‐axis plots Annexin‐V signal. E, Immunoblots of TGS‐04 cells with the same experimental conditions as in (D) for 4 d