The Pro-Apoptosis Bcl-2 Family Antibody Sampler Kit provides an economical means to examine several members of the Bcl-2 family and their activation status. The kit contains enough primary and secondary antibodies to perform two Western blot experiments per primary antibody.
Specificity / Sensitivity
Each antibody in the Pro- Apoptosis Bcl-2 Family Antibody Sampler Kit recognizes only its specific target. The antibodies do not cross-react with other Bcl-2 family members. Phospho-Bad (Ser112) (40A9) Rabbit mAb detects endogenous levels of Bad only when phosphorylated at Ser112 (mouse), Ser75 (human), or Ser113 (rat). Puma (D30C10) Rabbit mAb recognizes endogenous levels of total Puma protein but also cross-reacts with a protein of unknown origin at 60 kDa.
Source / Purification
Phospho-Bad (Ser112) (40A9) Rabbit mAb is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser112 of mouse Bad. Total Bad, Bax, Bim, Bak and Puma monoclonal antibodies are produced by immunizing animals with synthetic peptides corresponding to residues surrounding Pro102 of human Bad, Leu45 of human Bax, Pro25 of human Bim, Gly75 of human Bak, or near the carboxy terminus of human Puma. Polyclonal antibodies are produced by immunizing animals with synthetic peptides corresponding to the amino-terminus of human Bik or residues surrounding the cleavage site of human BID. Polyclonal antibodies are purified by protein A and peptide affinity chromatography.
The Bcl-2 family consists of a number of evolutionarily conserved proteins containing Bcl-2 homology domains (BH) that regulate apoptosis through control of mitochondrial membrane permeability and release of cytochrome c (1-3). Four BH domains have been identified (BH1-4) that mediate protein interactions. The family can be separated into three groups based upon function and sequence homology: pro-survival members include Bcl-2, Bcl-xL, Mcl-1, A1 and Bcl-w; pro-apoptotic proteins include Bax, Bak and Bok; and "BH3 only" proteins Bad, Bik, Bid, Puma, Bim, Bmf, Noxa and Hrk. Interactions between death-promoting and death-suppressing Bcl-2 family members has led to a rheostat model in which the ratio of pro-apoptotic and anti-apoptotic proteins controls cell fate (4). Thus, pro-survival members exert their behavior by binding to and antagonizing death-promoting members. In general, the "BH3-only members" can bind to and antagonize the pro-survival proteins leading to increased apoptosis (5). While some redundancy of this system likely exists, tissue specificity, transcriptional and post-translational regulation of many of these family members can account for distinct physiological roles.
Bad is a pro-apoptotic member of the Bcl-2 family that can displace Bax from binding to Bcl-2 and Bcl-xL, resulting in cell death (6,7). Survival factors such as IL-3 can inhibit the apoptotic activity of Bad by activating intracellular signaling pathways that result in the phosphorylation of Bad at Ser112 and Ser136 (7). Phosphorylation at these sites results in the binding of Bad to 14-3-3 proteins and the inhibition of Bad binding to Bcl-2 and Bcl-xL (7). Akt has been shown to promote cell survival via its ability to phosphorylate Bad at Ser136 (8,9). Ser112 has been shown to be the substrate in vivo and in vitro of p90RSK (10,11) and mitochondria-anchored PKA (12).