Background: Apoptosis or programmed cell death is a physiological cellular process characterized by cell shrinkage, membrane blebbing, DNA fragmentation, and release of Cytochrome C from the mitochondria. It is utilized by the organism to get rid of unwanted cells, which is critical for normal development and homeostasis of an organism. Disregulation of normal apoptosis process have been implicated in a variety of diseases, including cancer, autoimmune diseases, viral infections, etc. Programmed cell death occurs through complex cascades of cell signaling in which Bcl-2 family members, among others, play an important role.The Bcl-2 family of proteins regulate apoptosis as well as execute death signals at the mitochondrion. Members of this family include both pro- and anti-apoptotic proteins that hare homology sequences called Bcl-2 Homology domains (BH1-4) which mediate dimmer formation. The BH3 proteins, such as BID, NOXA, PUMA, BIK, BIM and BAD are all pro-apoptotic and share sequence homology within the amphipathic alpha-helical BH3 region, which is required for their apoptotic function. They may trigger release of death-inducing molecules such as Cytochrome C, Smac, and endonuclease G. Anti-apoptotic family members, including Bcl-2 and Bcl-XL, play inhibitory roles. Bcl-2 family proteins may form homodimers or heterodimers between pro- and anti-apoptotic members, the ratios of which determine the cell fate.