Figure 2.

Bok only interacts with selective anti-apoptotic Bcl-2 proteins in the yeast two-hybrid system. (A) Upper: yeast cells were grown in the selective media containing 5 mM 3-aminotriazole and without tryptophan, leucine, and histidine. Prominent growth of yeast colonies expressing Bok fused to the GAL4 activation domain together with Mcl-1, BHRF1, or Bfl-1 fused to the GAL4 binding domain could be seen. Minimal growth of yeast colonies was found in cells that express the same Bok expressing vector together with Bcl-2, Bcl-xL, Bcl-w, BAD, Bax, Bak, or Bik fused to the GAL4 binding domain. In addition, prominent growth of colonies expressing Bcl-xL and different pro-apoptotic Bcl-2 proteins indicated that the lack of growth in yeast cells expressing Bok and different pro-apoptotic family members was not due to suppression of cell growth by these pro-apoptotic proteins. Lower: growth of yeast colonies transformed with the same vector pairs maintained in a nonselective media. (B) Summary of protein-protein interactions between pairs of pro-apoptotic proteins (Bok, Bak, Bik, and Bax) and different anti-apoptotic Bcl-2 members. The positive signs indicate prominent (++) or moderate (+) yeast cell growth whereas the negative signs (−) indicate the absence of reporter gene expression.