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2me9

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Solution structure of BCL-xL containing the alpha1-alpha2 disordered loop determined with selective isotope labelling of I,L,V sidechains

Structural highlights

2me9 is a 1 chain structure with sequence from Homo sapiens. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Solution NMR
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

B2CL1_HUMAN Potent inhibitor of cell death. Inhibits activation of caspases (By similarity). Appears to regulate cell death by blocking the voltage-dependent anion channel (VDAC) by binding to it and preventing the release of the caspase activator, CYC1, from the mitochondrial membrane. Also acts as a regulator of G2 checkpoint and progression to cytokinesis during mitosis.^[1] ^[2] Isoform Bcl-X(S) promotes apoptosis.^[3] ^[4]

Publication Abstract from PubMed

Under conditions of genotoxic stress, human p53 activates the apoptotic effectors BAX or BAK to result in mitochondrial outer-membrane permeabilization and apoptosis. Antiapoptotic BCL-2 family member BCL-xL opposes this activity by sequestering cytosolic p53 via association with its DNA-binding domain, an interaction enhanced by p53 tetramerization. Here we characterized the BCL-xL-p53 complex by NMR spectroscopy and modulated it through mutagenesis to determine the relative contributions of BCL-xL's interactions with p53 or other BCL-2 family proteins to the BCL-xL-dependent inhibition of UV irradiation-induced apoptosis. Under our experimental conditions, one-third of the antiapoptotic activity of BCL-xL was mediated by p53 sequestration and the remaining two-thirds through sequestration of proapoptotic BCL-2 family members. Our studies define the contributions of cytosolic p53 to UV irradiation-induced apoptosis and provide opportunities to explore its contributions to other p53-dependent apoptotic signaling pathways.

The DNA-binding domain mediates both nuclear and cytosolic functions of p53.,Follis AV, Llambi F, Ou L, Baran K, Green DR, Kriwacki RW Nat Struct Mol Biol. 2014 Jun;21(6):535-43. doi: 10.1038/nsmb.2829. Epub 2014 May, 11. PMID:24814347^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Terrano DT, Upreti M, Chambers TC. Cyclin-dependent kinase 1-mediated Bcl-xL/Bcl-2 phosphorylation acts as a functional link coupling mitotic arrest and apoptosis. Mol Cell Biol. 2010 Feb;30(3):640-56. doi: 10.1128/MCB.00882-09. Epub 2009 Nov, 16. PMID:19917720 doi:10.1128/MCB.00882-09
↑ Wang J, Beauchemin M, Bertrand R. Bcl-xL phosphorylation at Ser49 by polo kinase 3 during cell cycle progression and checkpoints. Cell Signal. 2011 Dec;23(12):2030-8. doi: 10.1016/j.cellsig.2011.07.017. Epub, 2011 Aug 5. PMID:21840391 doi:10.1016/j.cellsig.2011.07.017
↑ Terrano DT, Upreti M, Chambers TC. Cyclin-dependent kinase 1-mediated Bcl-xL/Bcl-2 phosphorylation acts as a functional link coupling mitotic arrest and apoptosis. Mol Cell Biol. 2010 Feb;30(3):640-56. doi: 10.1128/MCB.00882-09. Epub 2009 Nov, 16. PMID:19917720 doi:10.1128/MCB.00882-09
↑ Wang J, Beauchemin M, Bertrand R. Bcl-xL phosphorylation at Ser49 by polo kinase 3 during cell cycle progression and checkpoints. Cell Signal. 2011 Dec;23(12):2030-8. doi: 10.1016/j.cellsig.2011.07.017. Epub, 2011 Aug 5. PMID:21840391 doi:10.1016/j.cellsig.2011.07.017
↑ Follis AV, Llambi F, Ou L, Baran K, Green DR, Kriwacki RW. The DNA-binding domain mediates both nuclear and cytosolic functions of p53. Nat Struct Mol Biol. 2014 Jun;21(6):535-43. doi: 10.1038/nsmb.2829. Epub 2014 May, 11. PMID:24814347 doi:http://dx.doi.org/10.1038/nsmb.2829