Accelerates programmed cell death by binding to, and antagonizing the apoptosis repressor BCL2 or its adenovirus homolog E1B 19k protein. Under stress conditions, undergoes a conformation change that causes translocation to the mitochondrion membrane, leading to the release of cytochrome c that then triggers apoptosis. Promotes activation of CASP3, and thereby apoptosis. Homodimer. Forms higher oligomers under stress conditions. Interacts with BCL2L11. Interaction with BCL2L11 promotes BAX oligomerization and association with mitochondrial membranes, with subsequent release of cytochrome c. Forms heterodimers with BCL2, E1B 19K protein, BCL2L1 isoform Bcl-X(L), BCL2L2, MCL1 and A1. Interacts with SH3GLB1 and HN. Interacts with SFN and YWHAZ; the interaction occurs in the cytoplasm. Under stress conditions, JNK-mediated phosphorylation of SFN and YWHAZ, releases BAX to mitochondria. Isoform Sigma interacts with BCL2A1 and BCL2L1 isoform Bcl-X(L). Interacts with RNF144B, which regulates the ubiquitin-dependent stability of BAX. Interacts with CLU under stress conditions that cause a conformation change leading to BAX oligomerization and association with mitochondria. Does not interact with CLU in unstressed cells. Interacts with FAIM2/LFG2. Interacts with human cytomegalovirus/HHV-5 protein vMIA/UL37. Expressed in a wide variety of tissues. Isoform Psi is found in glial tumors. Isoform Alpha is expressed in spleen, breast, ovary, testis, colon and brain, and at low levels in skin and lung. Isoform Sigma is expressed in spleen, breast, ovary, testis, lung, colon, brain and at low levels in skin. Isoform Alpha and isoform Sigma are expressed in pro- myelocytic leukemia, histiocytic lymphoma, Burkitt's lymphoma, T- cell lymphoma, lymphoblastic leukemia, breast adenocarcinoma, ovary adenocarcinoma, prostate carcinoma, prostate adenocarcinoma, lung carcinoma, epidermoid carcinoma, small cell lung carcinoma and colon adenocarcinoma cell lines. Belongs to the Bcl-2 family. 8 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Protein type: Apoptosis; Membrane protein, integral; Mitochondrial; Tumor suppressor
Molecular Function: BH3 domain binding; channel activity; identical protein binding; lipid binding; protein binding; protein heterodimerization activity; protein homodimerization activity
Biological Process: apoptosis; apoptotic mitochondrial changes; B cell apoptosis; caspase activation; caspase activation via cytochrome c; DNA damage response, signal transduction by p53 class mediator resulting in cell cycle arrest; endoplasmic reticulum calcium ion homeostasis; establishment and/or maintenance of transmembrane electrochemical gradient; induction of apoptosis via death domain receptors; mitochondrial fragmentation during apoptosis; mitochondrial fusion; negative regulation of protein binding; positive regulation of apoptosis; positive regulation of neuron apoptosis; positive regulation of protein oligomerization; protein homooligomerization; protein insertion into mitochondrial membrane during induction of apoptosis; protein oligomerization; regulation of apoptosis; regulation of mitochondrial membrane potential; regulation of protein heterodimerization activity; regulation of protein homodimerization activity; release of cytochrome c from mitochondria; release of matrix enzymes from mitochondria; response to toxin; unfolded protein response, activation of signaling protein activity