| Structural highlights
Function
[BAX_HUMAN] 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.[1] [2] [3] [4] [5] [6] [B2L11_HUMAN] Induces apoptosis and anoikis. Isoform BimL is more potent than isoform BimEL. Isoform Bim-alpha1, isoform Bim-alpha2 and isoform Bim-alpha3 induce apoptosis, although less potent than isoform BimEL, isoform BimL and isoform BimS. Isoform Bim-gamma induces apoptosis. Isoform Bim-alpha3 induces apoptosis possibly through a caspase-mediated pathway. Isoform BimAC and isoform BimABC lack the ability to induce apoptosis.[7] [8] [9] [10] [11] [12]
Publication Abstract from PubMed
The BH3-only protein Bim is a potent direct activator of the proapoptotic effector protein Bax, but the structural basis for its activity has remained poorly defined. Here we describe the crystal structure of the BimBH3 peptide bound to BaxDeltaC26 and structure-based mutagenesis studies. Similar to BidBH3, the BimBH3 peptide binds into the cognate surface groove of Bax using the conserved hydrophobic BH3 residues h1-h4. However, the structure and mutagenesis data show that Bim is less reliant compared with Bid on its 'h0' residues for activating Bax and that a single amino-acid difference between Bim and Bid encodes a fivefold difference in Bax-binding potency. Similar to the structures of BidBH3 and BaxBH3 bound to BaxDeltaC21, the structure of the BimBH3 complex with BaxDeltaC displays a cavity surrounded by Bax alpha1, alpha2, alpha5 and alpha8. Our results are consistent with a model in which binding of an activator BH3 domain to the Bax groove initiates separation of its core (alpha2-alpha5) and latch (alpha6-alpha8) domains, enabling its subsequent dimerisation and the permeabilisation of the mitochondrial outer membrane.
Crystal structure of Bax bound to the BH3 peptide of Bim identifies important contacts for interaction.,Robin AY, Krishna Kumar K, Westphal D, Wardak AZ, Thompson GV, Dewson G, Colman PM, Czabotar PE Cell Death Dis. 2015 Jul 9;6:e1809. doi: 10.1038/cddis.2015.141. PMID:26158515[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Oltvai ZN, Milliman CL, Korsmeyer SJ. Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death. Cell. 1993 Aug 27;74(4):609-19. PMID:8358790
- ↑ Schmitt E, Paquet C, Beauchemin M, Dever-Bertrand J, Bertrand R. Characterization of Bax-sigma, a cell death-inducing isoform of Bax. Biochem Biophys Res Commun. 2000 Apr 21;270(3):868-79. PMID:10772918 doi:http://dx.doi.org/10.1006/bbrc.2000.2537
- ↑ Chittenden T, Flemington C, Houghton AB, Ebb RG, Gallo GJ, Elangovan B, Chinnadurai G, Lutz RJ. A conserved domain in Bak, distinct from BH1 and BH2, mediates cell death and protein binding functions. EMBO J. 1995 Nov 15;14(22):5589-96. PMID:8521816
- ↑ Zhang H, Kim JK, Edwards CA, Xu Z, Taichman R, Wang CY. Clusterin inhibits apoptosis by interacting with activated Bax. Nat Cell Biol. 2005 Sep;7(9):909-15. Epub 2005 Aug 21. PMID:16113678 doi:http://dx.doi.org/10.1038/ncb1291
- ↑ Gavathiotis E, Suzuki M, Davis ML, Pitter K, Bird GH, Katz SG, Tu HC, Kim H, Cheng EH, Tjandra N, Walensky LD. BAX activation is initiated at a novel interaction site. Nature. 2008 Oct 23;455(7216):1076-81. PMID:18948948 doi:10.1038/nature07396
- ↑ Czabotar PE, Lee EF, Thompson GV, Wardak AZ, Fairlie WD, Colman PM. Mutation to Bax beyond the BH3 domain disrupts interactions with pro-survival proteins and promotes apoptosis. J Biol Chem. 2011 Mar 4;286(9):7123-31. Epub 2011 Jan 3. PMID:21199865 doi:10.1074/jbc.M110.161281
- ↑ O'Connor L, Strasser A, O'Reilly LA, Hausmann G, Adams JM, Cory S, Huang DC. Bim: a novel member of the Bcl-2 family that promotes apoptosis. EMBO J. 1998 Jan 15;17(2):384-95. PMID:9430630 doi:http://dx.doi.org/10.1093/emboj/17.2.384
- ↑ U M, Miyashita T, Shikama Y, Tadokoro K, Yamada M. Molecular cloning and characterization of six novel isoforms of human Bim, a member of the proapoptotic Bcl-2 family. FEBS Lett. 2001 Nov 30;509(1):135-41. PMID:11734221
- ↑ Liu JW, Chandra D, Tang SH, Chopra D, Tang DG. Identification and characterization of Bimgamma, a novel proapoptotic BH3-only splice variant of Bim. Cancer Res. 2002 May 15;62(10):2976-81. PMID:12019181
- ↑ Marani M, Tenev T, Hancock D, Downward J, Lemoine NR. Identification of novel isoforms of the BH3 domain protein Bim which directly activate Bax to trigger apoptosis. Mol Cell Biol. 2002 Jun;22(11):3577-89. PMID:11997495
- ↑ Chen JZ, Ji CN, Gu SH, Li JX, Zhao EP, Huang Y, Huang L, Ying K, Xie Y, Mao YM. Over-expression of Bim alpha3, a novel isoform of human Bim, result in cell apoptosis. Int J Biochem Cell Biol. 2004 Aug;36(8):1554-61. PMID:15147734 doi:http://dx.doi.org/10.1016/j.biocel.2003.12.015
- ↑ Fukazawa H, Noguchi K, Masumi A, Murakami Y, Uehara Y. BimEL is an important determinant for induction of anoikis sensitivity by mitogen-activated protein/extracellular signal-regulated kinase kinase inhibitors. Mol Cancer Ther. 2004 Oct;3(10):1281-8. PMID:15486195
- ↑ Robin AY, Krishna Kumar K, Westphal D, Wardak AZ, Thompson GV, Dewson G, Colman PM, Czabotar PE. Crystal structure of Bax bound to the BH3 peptide of Bim identifies important contacts for interaction. Cell Death Dis. 2015 Jul 9;6:e1809. doi: 10.1038/cddis.2015.141. PMID:26158515 doi:http://dx.doi.org/10.1038/cddis.2015.141
|
