Baughman Brandi M, Pattenden Samantha G, Norris Jacqueline L, James Lindsey I, Frye Stephen V
Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
ACS Chem Biol. 2016 Mar 18;11(3):722-8. doi: 10.1021/acschembio.5b00632. Epub 2015 Sep 2.
L3MBTL3 recognizes mono- and dimethylated lysine residues on histone tails. The recently reported X-ray cocrystal structures of the chemical probe UNC1215 and inhibitor UNC2533 bound to the methyl-lysine reading MBT domains of L3MBTL3 demonstrate a unique and flexible 2:2 dimer mode of recognition. In this study, we describe our in vitro analysis of L3MBTL3 dimerization via its MBT domains and additionally show that this dimerization occurs within a cellular context in the absence of small molecule ligands. Furthermore, mutations to the first and second MBT domains abrogated L3MBTL3 dimerization both in vitro and in cells. These observations are consistent with the hypothesis that L3MBTL3 engages methylated histone tails as a dimer while carrying out its normal function and provides an explanation for the presence of repeated MBT domains within L3MBTL3.
L3MBTL3可识别组蛋白尾部的单甲基化和二甲基化赖氨酸残基。最近报道的与L3MBTL3的甲基赖氨酸识别MBT结构域结合的化学探针UNC1215和抑制剂UNC2533的X射线共晶体结构显示了一种独特且灵活的2:2二聚体识别模式。在本研究中，我们描述了通过其MBT结构域对L3MBTL3二聚化的体外分析，此外还表明这种二聚化在没有小分子配体的细胞环境中也会发生。此外，对第一个和第二个MBT结构域的突变在体外和细胞中都消除了L3MBTL3的二聚化。这些观察结果与以下假设一致，即L3MBTL3在执行其正常功能时以二聚体形式结合甲基化组蛋白尾部，并为L3MBTL3中重复MBT结构域的存在提供了解释。
