1k1b
From Proteopedia
Crystal structure of the ankyrin repeat domain of Bcl-3: a unique member of the IkappaB protein family
Structural highlights
DiseaseBCL3_HUMAN Note=A chromosomal aberration involving BCL3 may be a cause of B-cell chronic lymphocytic leukemia (B-CLL). Translocation t(14;19)(q32;q13.1) with immunoglobulin gene regions. FunctionBCL3_HUMAN Contributes to the regulation of transcriptional activation of NF-kappa-B target genes. In the cytoplasm, inhibits the nuclear translocation of the NF-kappa-B p50 subunit. In the nucleus, acts as transcriptional activator that promotes transcription of NF-kappa-B target genes. Contributes to the regulation of cell proliferation (By similarity).[1] 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 PubMedIkappaB proteins associate with the transcription factor NF-kappaB via their ankyrin repeat domain. Bcl-3 is an unusual IkappaB protein because it is primarily nucleoplasmic and can lead to enhanced NF-kappaB-dependent transcription, unlike the prototypical IkappaB protein IkappaBalpha, which inhibits NF-kappaB activity by retaining it in the cytoplasm. Here we report the 1.9 A crystal structure of the ankyrin repeat domain of human Bcl-3 and compare it with that of IkappaBalpha bound to NF-kappaB. The two structures are highly similar over the central ankyrin repeats but differ in the N-terminal repeat and at the C-terminus, where Bcl-3 contains a seventh repeat in place of the acidic PEST region of IkappaBalpha. Differences between the two structures suggest why Bcl-3 differs from IkappaBalpha in selectivity towards various NF-kappaB species, why Bcl-3 but not IkappaBalpha can associate with its NF-kappaB partner bound to DNA, and why two molecules of Bcl-3 but only one of IkappaBalpha can bind to its NF-kappaB partner. Comparison of the two structures thus provides an insight into the functional diversity of IkappaB proteins. Crystal structure of the ankyrin repeat domain of Bcl-3: a unique member of the IkappaB protein family.,Michel F, Soler-Lopez M, Petosa C, Cramer P, Siebenlist U, Muller CW EMBO J. 2001 Nov 15;20(22):6180-90. PMID:11707390[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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