Apoptosis is inhibited by

The integrity of the mitochondrial outer membrane is regulated by pro-apoptotic and anti-apoptotic members of the BCL2 family of proteins. The pro-apoptotic proteins BAX and BAK are directly promoting mitochondrial permeabilization. Their action is inhibited by the anti-apoptotic proteins BCL2 and BCL-XL. The third set of proteins, the so-called BH3-only proteins, which include BAD, BID, and PUMA, regulate the balance between the pro- and anti-apoptotic members of the BCL2 family.( Robbins Basic Pathology, 9th edition, page 189 )