Structural highlights
Disease
[BCL9_HUMAN] Note=A chromosomal aberration involving BCL9 is found in a patient with precusor B-cell acute lymphoblastic leukemia (ALL). Translocation t(1;14)(q21;q32). This translocation leaves the coding region intact, but may have pathogenic effects due to alterations in the expression level of BCL9. Several cases of translocations within the 3'-UTR of BCL9 have been found in B-cell malignancies.
Function
[BCL9_HUMAN] Involved in signal transduction through the Wnt pathway. Promotes beta-catenin's transcriptional activity (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 PubMed
Pygo and BCL9/Legless transduce the Wnt signal by promoting the transcriptional activity of beta-catenin/Armadillo in normal and malignant cells. We show that human and Drosophila Pygo PHD fingers associate with their cognate HD1 domains from BCL9/Legless to bind specifically to the histone H3 tail methylated at lysine 4 (H3K4me). The crystal structures of ternary complexes between PHD, HD1, and two different H3K4me peptides reveal a unique mode of histone tail recognition: efficient histone binding requires HD1 association, and the PHD-HD1 complex binds preferentially to H3K4me2 while displaying insensitivity to methylation of H3R2. Therefore, this is a prime example of histone tail binding by a PHD finger (of Pygo) being modulated by a cofactor (BCL9/Legless). Rescue experiments in Drosophila indicate that Wnt signaling outputs depend on histone decoding. The specificity of this process provided by the Pygo-BCL9/Legless complex suggests that this complex facilitates an early step in the transition from gene silence to Wnt-induced transcription.
Decoding of methylated histone H3 tail by the Pygo-BCL9 Wnt signaling complex.,Fiedler M, Sanchez-Barrena MJ, Nekrasov M, Mieszczanek J, Rybin V, Muller J, Evans P, Bienz M Mol Cell. 2008 May 23;30(4):507-18. PMID:18498752[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kramps T, Peter O, Brunner E, Nellen D, Froesch B, Chatterjee S, Murone M, Zullig S, Basler K. Wnt/wingless signaling requires BCL9/legless-mediated recruitment of pygopus to the nuclear beta-catenin-TCF complex. Cell. 2002 Apr 5;109(1):47-60. PMID:11955446
- ↑ Fiedler M, Sanchez-Barrena MJ, Nekrasov M, Mieszczanek J, Rybin V, Muller J, Evans P, Bienz M. Decoding of methylated histone H3 tail by the Pygo-BCL9 Wnt signaling complex. Mol Cell. 2008 May 23;30(4):507-18. PMID:18498752 doi:10.1016/j.molcel.2008.03.011
