Structural highlights
Function
[SIN3B_MOUSE] Acts as a transcriptional repressor. Interacts with MXI1 to repress MYC responsive genes and antagonize MYC oncogenic activities. Interacts with MAD-MAX heterodimers by binding to MAD. The heterodimer then represses transcription by tethering SIN3B to DNA. Also forms a complex with FOXK1 which represses transcription.[1] [2] [MAD1_HUMAN] Transcriptional repressor. MAD binds with MAX to form a sequence-specific DNA-binding protein complex which recognizes the core sequence 5'-CAC[GA]TG-3'. MAD thus antagonizes MYC transcriptional activity by competing for MAX.
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 PubMed
Sin3A or Sin3B are components of a corepressor complex that mediates repression by transcription factors such as the helix-loop-helix proteins Mad and Mxi. Members of the Mad/Mxi family of repressors play important roles in the transition between proliferation and differentiation by down-regulating the expression of genes that are activated by the proto-oncogene product Myc. Here, we report the solution structure of the second paired amphipathic helix (PAH) domain (PAH2) of Sin3B in complex with a peptide comprising the N-terminal region of Mad1. This complex exhibits a novel interaction fold for which we propose the name 'wedged helical bundle'. Four alpha-helices of PAH2 form a hydrophobic cleft that accommodates an amphipathic Mad1 alpha-helix. Our data further show that, upon binding Mad1, secondary structure elements of PAH2 are stabilized. The PAH2-Mad1 structure provides the basis for determining the principles of protein interaction and selectivity involving PAH domains.
The Mad1-Sin3B interaction involves a novel helical fold.,Spronk CA, Tessari M, Kaan AM, Jansen JF, Vermeulen M, Stunnenberg HG, Vuister GW Nat Struct Biol. 2000 Dec;7(12):1100-4. PMID:11101889[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Ayer DE, Lawrence QA, Eisenman RN. Mad-Max transcriptional repression is mediated by ternary complex formation with mammalian homologs of yeast repressor Sin3. Cell. 1995 Mar 10;80(5):767-76. PMID:7889570
- ↑ Yang Q, Kong Y, Rothermel B, Garry DJ, Bassel-Duby R, Williams RS. The winged-helix/forkhead protein myocyte nuclear factor beta (MNF-beta) forms a co-repressor complex with mammalian sin3B. Biochem J. 2000 Jan 15;345 Pt 2:335-43. PMID:10620510
- ↑ Spronk CA, Tessari M, Kaan AM, Jansen JF, Vermeulen M, Stunnenberg HG, Vuister GW. The Mad1-Sin3B interaction involves a novel helical fold. Nat Struct Biol. 2000 Dec;7(12):1100-4. PMID:11101889 doi:http://dx.doi.org/10.1038/81944
