Fig. 7. Sequential proteolysis of proteins from the nuclear envelope in cell cultures undergoing apoptosis. (A) BRL cells were treated with 1 µM staurosporine for different times. Equivalent amounts of total proteins of control or treated cell cultures were separated by SDS-PAGE and analyzed by western blotting using anti-POM121, mAb414 (NUP153 and p62) or anti-lamin B antibodies. The panel of western blots is representative of one experiment. (B) Mean t₅₀ values of quantified western blots from four separate experiments. Bars denoted with different letters are significantly different (a-c). (C) BRL cells were treated with 1 µM staurosporine and the caspase inhibitor was added either 1 hour before (1h inhibitor +STSP), or 1 hour after addition of staurosporine (1 h STSP +inhibitor) or cells were incubated with staurosporine alone (STSP). The panel of western blots is representative of one experiment.