(A and C) TAK1-/- MEF cells reconstituted with empty vector and TAK1 were either untreated or treated with LPA (A) or PMA/Iono (C) for 0, 30, and 60 min, then harvested. WCL and nuclear extracts were subjected to SDS-PAGE and immunoblotting analysis as indicated. (B and D) TAK1-/- MEF cells reconstituted with empty vector and TAK1 expression plasmid were either untreated or treated with LPA (B) or PMA/Iono (D) for 0, 5, 15, 30, and 60 min, then harvested. WCL were subjected to SDS-PAGE and immunoblotting analysis as indicated.