FunctionSuppresses apoptosis in a variety of cell systems including factor-dependent lymphohematopoietic and neural cells. Regulates cell death by controlling the mitochondrial membrane permeability. Appears to function in a feedback loop system with caspases. Inhibits caspase activity either by preventing the release of cytochrome c from the mitochondria and/or by binding to the apoptosis-activating factor （APAF-1）.

• Tissue specificityExpressed in a variety of tissues.
• Involvement in diseaseNote=A chromosomal aberration involving BCL2 has been found in chronic lymphatic leukemia. Translocation t（14;18）（q32;q21） with immunoglobulin gene regions. BCL2 mutations found in non-Hodgkin lymphomas carrying the chromosomal translocation could be attributed to the Ig somatic hypermutation mechanism resulting in nucleotide transitions.
• Sequence similaritiesBelongs to the Bcl-2 family.
• DomainThe BH4 motif is required for anti-apoptotic activity and for interaction with RAF1 and EGLN3.
• Post-translational
  modificationsPhosphorylation/dephosphorylation on Ser-70 regulates anti-apoptotic activity. Growth factor-stimulated phosphorylation on Ser-70 by PKC is required for the anti-apoptosis activity and occurs during the G2/M phase of the cell cycle. In the absence of growth factors, BCL2 appears to be phosphorylated by other protein kinases such as ERKs and stress-activated kinases. Phosphorylated by MAPK8/JNK1 at Thr-69, Ser-70 and Ser-87, wich stimulates starvation-induced autophagy. Dephosphorylated by protein phosphatase 2A （PP2A）.
  Proteolytically cleaved by caspases during apoptosis. The cleaved protein, lacking the BH4 motif, has pro-apoptotic activity, causes the release of cytochrome c into the cytosol promoting further caspase activity.
  Monoubiquitinated by PARK2, leading to increase its stability.
• Cellular localizationMitochondrion outer membrane. Nucleus membrane. Endoplasmic reticulum membrane.