Protein analysis in ALL cell lines reveals BCL-2, BIM, and BID are complexed. CHAPS lysates of the 4 ALL cell lines were used for protein experiments. (A) Western blot analysis of lysate (20 μg) reveals different expression of BCL-2, MCL-1, BIM, and BID among the cell lines. (B) Quantification of proteins bands by densitometry verifies that BCL-2 and BIM protein expression levels follow the rank order of whole-cell ABT-737 sensitivity and BAD-induced cytochrome c release: RS4;11 > SEM-k2 > 697 > CEMc-1. (C) Anti–BCL-2 immunoprecipitation of ALL cells lines (50 μg). Immunoprecipitation pellet (i.p.) and 10% of total lysate used for immunoprecipitation (input) were loaded. BIM and BID are complexed to BCL-2 in amounts proportional to whole-cell amounts.