Bcl-2-associated X protein
| BCL2-associated X protein
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| Based on PDB id 1F16
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| Available structures: 1f16
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| Identifiers
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| Symbol(s)
| BAX; Bax zeta
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| External IDs
| OMIM: 600040 MGI: 99702 Homologene: 7242
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| Gene Ontology
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| Molecular Function:
| • molecular_function • protein binding • BH3 domain binding
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| Cellular Component:
| • cellular_component • soluble fraction • cytoplasm • mitochondrion • mitochondrial outer membrane • membrane • integral to membrane • cytosolic part
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| 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
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| RNA expression pattern
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More reference expression data
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| Orthologs
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| Human
| Mouse
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| Entrez
| 581
| 12028
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| Ensembl
| ENSG00000087088
| ENSMUSG00000003873
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| Uniprot
| Q07814
| Q3TXJ7
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| Refseq
| NM_004324 (mRNA) NP_004315 (protein)
| NM_007527 (mRNA) NP_031553 (protein)
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| Location
| Chr 19: 54.15 - 54.16 Mb
| Chr 7: 45.33 - 45.33 Mb
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| Pubmed search
| [1]
| [2]
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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
References
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Oltvai, Z. N.; Milliman, C. L. and Korsmeyer, S. J. (August 1993). "Bcl-2 Heterodimerizes In Vivo with a Conserved Homolog, Bax, That Accelerates Programed Cell Death". Cell 74: 609-619.
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Wolter, K. G.; Hsu, Y., Smith, C. L., Mechushtan, A., Xi, X., and Youle, R. J. (December 1997). "Movement of Bax from Cytosol to Mitochondria during Apoptosis". Journal of Cell Biology 139: 1281-1292.
Further reading
- Vieira HL, Haouzi D, El Hamel C, et al. (2001). "Permeabilization of the mitochondrial inner membrane during apoptosis: impact of the adenine nucleotide translocator.". Cell Death Differ. 7 (12): 1146-54. doi:10.1038/sj.cdd.4400778. PMID 11175251.
- Buytaert E, Callewaert G, Vandenheede JR, Agostinis P (2007). "Deficiency in apoptotic effectors Bax and Bak reveals an autophagic cell death pathway initiated by photodamage to the endoplasmic reticulum.". Autophagy 2 (3): 238-40. PMID 16874066.
- Steele AD, Yi CH (2007). "Neuromuscular denervation: Bax up against the wall in amyotrophic lateral sclerosis.". J. Neurosci. 26 (50): 12849-51. PMID 17171827.
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