HEK293T cells were transfected with the pCMV6-ENTRY control (Cat# PS100001, Left lane) or pCMV6-ENTRY SMAD1 (Cat# RC223918, Right lane) cDNA for 48 hrs and lysed. Equivalent amounts of cell lysates (5 ug per lane) were separated by SDS-PAGE and immunoblotted with anti-SMAD1 (Cat# TA507245)(1:500).