Promotes cell survival. Blocks dexamethasone-induced apoptosis. Mediates survival of postmitotic Sertoli cells by suppressing death-promoting activity of BAX. Interacts with HIF3A isoform 2 (via C-terminus domain) (PubMed:21546903). Interacts with BOP (By similarity). Loosely associated with the mitochondrial membrane in healthy cells. During apoptosis, tightly bound to the membrane (By similarity). Expressed in almost all myeloid cell lines and in a wide range of tissues, with highest levels in brain, colon, and salivary gland. Expressed in both mitotic and postmitotic Sertoli cells. By Igf1. The BH4 motif seems to be involved in the anti-apoptotic function. The BH1 and BH2 motifs form a hydrophobic groove which acts as a docking site for the BH3 domain of some pro-apoptotic proteins. The C-terminal residues of BCL2L2 fold into the BH3-binding cleft and modulate pro-survival activity by regulating ligand access. When BH3 domain-containing proteins bind, they displace the C-terminus, allowing its insertion into the membrane and neutralizing the pro-survival activity of BCL2L2 (By similarity). Mice are sterile due to arrest in spermatogenesis associated with a gradual loss of germ and Sertoli cells from the testis. Belongs to the Bcl-2 family.