Bcl-2-associated X protein

BCL2-associated X protein
Based on PDB id 1F16
Available structures: 1f16
Identifiers
Symbol(s)	BAX; Bax zeta
External IDs	OMIM: 600040 MGI: 99702 Homologene: 7242
Gene Ontology Molecular Function: • molecular_function • protein binding • BH3 domain binding Cellular Component: • cellular_component • soluble fraction • cytoplasm • mitochondrion • mitochondrial outer membrane • membrane • integral to membrane • cytosolic part Biological Process: • release of cytochrome c from mitochondria • protein insertion into mitochondrial membrane during induction of apoptosis • apoptosis • induction of apoptosis • response to DNA damage stimulus • cell cycle • germ cell development • spermatogenesis • nervous system development • induction of apoptosis by extracellular signals • induction of apoptosis by intracellular signals • negative regulation of survival gene product activity • caspase activation via cytochrome c • apoptotic mitochondrial changes • response to wounding • nuclear fragmentation during apoptosis • regulation of apoptosis • regulation of caspase activity • negative regulation of progression through cell cycle • retinal cell programmed cell death • negative regulation of fibroblast proliferation • protein homooligomerization
RNA expression pattern
Additional recommended knowledge Weighing the right way Recognize and detect the effects of electrostatic charges on your balance Essential Laboratory Skills Guide More reference expression data
Orthologs
	Human	Mouse
Entrez	581	12028
Ensembl	ENSG00000087088	ENSMUSG00000003873
Uniprot	Q07814	Q3TXJ7
Refseq	NM_004324 (mRNA) NP_004315 (protein)	NM_007527 (mRNA) NP_031553 (protein)
Location	Chr 19: 54.15 - 54.16 Mb	Chr 7: 45.33 - 45.33 Mb
Pubmed search	[1]	[2]

The Bcl-2–associated X protein, or BAX, gene was the first identified pro-apoptotic member of the Bcl-2 protein family.^[1] Bcl-2 family members share one or more of the four characteristic domains of homology entitled the Bcl-2 homology (BH) domains (named BH1, BH2, BH3 and BH4), and can form hetero- or homodimers. Bcl-2 proteins act as anti- or pro-apoptotic regulators that are involved in a wide variety of cellular activities.

Bax is a pro-apoptotic Bcl-2 protein containing BH1, BH2 and BH3 domains. In healthy mammalian cells, the majority of Bax is found in the cytosol, but upon initiation of apoptotic signaling, Bax undergoes a conformation shift, and inserts into organelle membranes, primarily the outer mitochondrial membrane.^[2] Bax is believed to interact with, and induce the opening of the mitochondrial voltage-dependent anion channel, VDAC. Alternatively, growing evidence suggest that activated Bax and/or Bak form an oligomeric pore, MAC in the outer membrane. This results in the the release of cytochrome c and other pro-apoptotic factors from the mitochondria, often referred to as mitochondrial outer membrane permeabilization, leading to activation of caspases. This defines a direct role for Bax in mitochondrial outer membrane permeabilization, a role common to the Bcl-2 proteins containing the BH1, BH2 and BH3 domains.

The expression of BAX is upregulated by the tumor suppressor protein p53, and Bax has been shown to be involved in p53-mediated apoptosis. The p53 protein is a transcription factor that, when activated as part of the cell's response to stress, regulates many downstream target genes, including BAX. However, p53 also has a transcription-independent role in apoptosis. In particular, p53 interacts with Bax, promoting Bax activation and the insertion of Bax into the mitochondrial membrane.

See also

• Apoptosis
• Apoptosome
• Bcl-2
• BH3 interacting domain death agonist (BID)
• Caspases
• Cytochrome c
• Noxa
• Mitochondrion
• p53 upregulated modulator of apoptosis (PUMA)

References

Further reading