Structural highlights
Disease
AFF1_HUMAN Precursor B-cell acute lymphoblastic leukemia. A chromosomal aberration involving AFF1 is associated with acute leukemias. Translocation t(4;11)(q21;q23) with KMT2A/MLL1. The result is a rogue activator protein.AF9_HUMAN A chromosomal aberration involving MLLT3 is associated with acute leukemias. Translocation t(9;11)(p22;q23) with KMT2A/MLL1. The result is a rogue activator protein.
Function
AFF1_HUMAN AF9_HUMAN Component of the super elongation complex (SEC), a complex required to increase the catalytic rate of RNA polymerase II transcription by suppressing transient pausing by the polymerase at multiple sites along the DNA.[1] [2]
Publication Abstract from PubMed
Mixed lineage leukemia (MLL) fusion proteins cause oncogenic transformation of hematopoietic cells by constitutive recruitment of elongation factors to HOX promoters, resulting in overexpression of target genes. The structural basis of transactivation by MLL fusion partners remains undetermined. We show that the ANC1 homology domain (AHD) of AF9, one of the most common MLL translocation partners, is intrinsically disordered and recruits multiple transcription factors through coupled folding and binding. We determined the structure of the AF9 AHD in complex with the elongation factor AF4 and show that aliphatic residues, which are conserved in each of the AF9 binding partners, form an integral part of the hydrophobic core of the complex. Nuclear magnetic resonance relaxation measurements show that AF9 retains significant dynamic behavior which may facilitate exchange between disordered partners. We propose that AF9 functions as a signaling hub that regulates transcription through dynamic recruitment of cofactors in normal hematopoiesis and in acute leukemia.
Leukemia Fusion Target AF9 Is an Intrinsically Disordered Transcriptional Regulator that Recruits Multiple Partners via Coupled Folding and Binding.,Leach BI, Kuntimaddi A, Schmidt CR, Cierpicki T, Johnson SA, Bushweller JH Structure. 2012 Dec 19. pii: S0969-2126(12)00426-1. doi:, 10.1016/j.str.2012.11.011. PMID:23260655[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lin C, Smith ER, Takahashi H, Lai KC, Martin-Brown S, Florens L, Washburn MP, Conaway JW, Conaway RC, Shilatifard A. AFF4, a component of the ELL/P-TEFb elongation complex and a shared subunit of MLL chimeras, can link transcription elongation to leukemia. Mol Cell. 2010 Feb 12;37(3):429-37. doi: 10.1016/j.molcel.2010.01.026. PMID:20159561 doi:10.1016/j.molcel.2010.01.026
- ↑ He N, Liu M, Hsu J, Xue Y, Chou S, Burlingame A, Krogan NJ, Alber T, Zhou Q. HIV-1 Tat and host AFF4 recruit two transcription elongation factors into a bifunctional complex for coordinated activation of HIV-1 transcription. Mol Cell. 2010 May 14;38(3):428-38. doi: 10.1016/j.molcel.2010.04.013. PMID:20471948 doi:10.1016/j.molcel.2010.04.013
- ↑ Leach BI, Kuntimaddi A, Schmidt CR, Cierpicki T, Johnson SA, Bushweller JH. Leukemia Fusion Target AF9 Is an Intrinsically Disordered Transcriptional Regulator that Recruits Multiple Partners via Coupled Folding and Binding. Structure. 2012 Dec 19. pii: S0969-2126(12)00426-1. doi:, 10.1016/j.str.2012.11.011. PMID:23260655 doi:http://dx.doi.org/10.1016/j.str.2012.11.011
