Western blotting 20 ng of pure lamin A protein was subjected to digestion by different concentrations of caspase-3, -6, and -7 (0.75-6 mM) in caspase cleavage buffer for 30 min at 37uC. The reactions were stopped by shock-freezing, and thawed samples were run on 4-12% Bis-Tris gels (Nupage, Invitrogen), transferred to PVDF membranes by electroblotting and membranes were developed with primary antibodies in 5% BSA/PBS. Fluorescently labelled secondary antibodies and the LiCor Odyssey Infrared Imaging system were used for detection.