3bim | pdb_00003bim
Crystal structure of the BCL6 BTB domain dimer in complex with the BCOR BBD corepressor peptide
Structural highlights
Disease[BCL6_HUMAN] Note=Chromosomal aberrations involving BCL6 may be a cause of B-cell non-Hodgkin lymphoma. Translocation t(3;14)(q27;q32); translocation t(3;22)(q27;q11) with immunoglobulin gene regions. Note=A chromosomal aberration involving BCL6 may be a cause of a form of B-cell leukemia. Translocation t(3;11)(q27;q23) with POU2AF1/OBF1. Note=A chromosomal aberration involving BCL6 may be a cause of lymphoma. Translocation t(3;4)(q27;p11) with ARHH/TTF. [BCOR_HUMAN] Defects in BCOR are the cause of microphthalmia syndromic type 2 (MCOPS2) [MIM:300166]. Microphthalmia is a clinically heterogeneous disorder of eye formation, ranging from small size of a single eye to complete bilateral absence of ocular tissues (anophthalmia). In many cases, microphthalmia/anophthalmia occurs in association with syndromes that include non-ocular abnormalities. MCOPS2 is a very rare multiple congenital anomaly syndrome characterized by eye anomalies (congenital cataract, microphthalmia, or secondary glaucoma), facial abnormalities (long narrow face, high nasal bridge, pointed nose with cartilages separated at the tip, cleft palate, or submucous cleft palate), cardiac anomalies (atrial septal defect, ventricular septal defect, or floppy mitral valve) and dental abnormalities (canine radiculomegaly, delayed dentition, oligodontia, persistent primary teeth, or variable root length).[1] Function[BCL6_HUMAN] Transcriptional repressor which is required for germinal center formation and antibody affinity maturation. Probably plays an important role in lymphomagenesis.[2] [3] [BCOR_HUMAN] Transcriptional corepressor. May specifically inhibit gene expression when recruited to promoter regions by sequence specific DNA-binding proteins such as BCL6 and MLLT3. This repression may be mediated at least in part by histone deacetylase activities which can associate with this corepressor. Involved in the repression of TFAP2A; impairs binding of BCL6 and KDM2B to TFAP2A promoter regions. Via repression of TFAP2A acts as a negative regulator of osteo-dentiogenic capacity in adult stem cells; the function implies inhibition of methylation on histone H3 'Lys-4' (H3K4me3) and 'Lys-36' (H3K36me2).[4] [5] [6] [7] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe transcriptional corepressors BCOR, SMRT, and NCoR are known to bind competitively to the BCL6 BTB domain despite the fact that BCOR has no detectable sequence similarity to the other two corepressors. We have identified a 17 residue motif from BCOR that binds directly to the BCL6 BTB domain and determined the crystal structure of the complex to a resolution of 2.6 A. Remarkably, the BCOR BCL6 binding domain (BCOR(BBD)) peptide binds in the same BCL6 binding site as the SMRT(BBD) peptide despite the lack of any significant sequence similarity between the two peptides. Mutations of critical BCOR(BBD) residues cause the disruption of the BCL6 corepression activities of BCOR, and a BCOR(BBD) peptide blocks BCL6-mediated transcriptional repression and kills lymphoma cells. Structure of a BCOR corepressor peptide in complex with the BCL6 BTB domain dimer.,Ghetu AF, Corcoran CM, Cerchietti L, Bardwell VJ, Melnick A, Prive GG Mol Cell. 2008 Feb 15;29(3):384-91. PMID:18280243[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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