| Structural highlights
Function
[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.[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
Apoptosis is a key innate defence mechanism to eliminate virally infected cells. To counteract premature host-cell apoptosis, poxviruses have evolved numerous molecular strategies, including the use of Bcl-2 proteins, to ensure their own survival. Here, it is reported that the Deerpox virus inhibitor of apoptosis, DPV022, only engages a highly restricted set of death-inducing Bcl-2 proteins, including Bim, Bax and Bak, with modest affinities. Structural analysis reveals that DPV022 adopts a Bcl-2 fold with a dimeric domain-swapped topology and binds pro-death Bcl-2 proteins via two conserved ligand-binding grooves found on opposite sides of the dimer. Structures of DPV022 bound to Bim, Bak and Bax BH3 domains reveal that a partial obstruction of the binding groove is likely to be responsible for the modest affinities of DPV022 for BH3 domains. These findings reveal that domain-swapped dimeric Bcl-2 folds are not unusual and may be found more widely in viruses. Furthermore, the modest affinities of DPV022 for pro-death Bcl-2 proteins suggest that two distinct classes of anti-apoptotic viral Bcl-2 proteins exist: those that are monomeric and tightly bind a range of death-inducing Bcl-2 proteins, and others such as DPV022 that are dimeric and only bind a very limited number of death-inducing Bcl-2 proteins with modest affinities.
Structural basis of Deerpox virus-mediated inhibition of apoptosis.,Burton DR, Caria S, Marshall B, Barry M, Kvansakul M Acta Crystallogr D Biol Crystallogr. 2015 Aug 1;71(Pt 8):1593-603. doi:, 10.1107/S1399004715009402. Epub 2015 Jul 28. PMID:26249341[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ 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
- ↑ Burton DR, Caria S, Marshall B, Barry M, Kvansakul M. Structural basis of Deerpox virus-mediated inhibition of apoptosis. Acta Crystallogr D Biol Crystallogr. 2015 Aug 1;71(Pt 8):1593-603. doi:, 10.1107/S1399004715009402. Epub 2015 Jul 28. PMID:26249341 doi:http://dx.doi.org/10.1107/S1399004715009402
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