Phosphorylated Intrinsically Disordered Region of FACT Masks Its Nucleosomal DNA Binding Elements*
Phosphorylated Intrinsically Disordered Region of FACT Masks Its Nucleosomal DNA Binding Elements*
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DOI：
10.1074/jbc.m109.001958
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发表时间：
2009-07
期刊：
影响因子：
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通讯作者：
Y. Tsunaka;Junko Toga;H. Yamaguchi;S. Tate;S. Hirose;K. Morikawa
中科院分区：
文献类型：
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作者：
Y. Tsunaka;Junko Toga;H. Yamaguchi;S. Tate;S. Hirose;K. Morikawa
FACT是SPT16和SSRP 1的异二聚体，它们各自在一级结构中包含几个保守区域。FACT与核小体的相互作用通过其不同功能蛋白区域的组合作用诱导染色质重塑。然而，很少有机制的洞察这些地区如何合作有助于FACT功能，特别是关于核小体DNA的识别。在这里，我们报告的新的果蝇FACT（dFACT）在Sf9细胞中表达的磷酸化位点的鉴定。这些位点密集地集中在SSRP 1亚基的酸性固有无序（ID）区域，并通过dFACT控制核小体DNA结合。该区域和HMG结构域的相邻片段形成弱的静电分子内相互作用，其通过磷酸化增强，从而竞争性地阻断DNA结合。重要的是，这种控制机制似乎支持快速染色质交易在早期胚胎发生通过去磷酸化的一些网站在母体传播的dSSRP1。
FACT is a heterodimer of SPT16 and SSRP1, which each contain several conserved regions in the primary structure. The interaction of FACT with nucleosomes induces chromatin remodeling through the combinatorial action of its distinct functional protein regions. However, there is little mechanistic insight into how these regions cooperatively contribute to FACT functions, particularly regarding the recognition of nucleosomal DNA. Here, we report the identification of novel phosphorylation sites of Drosophila melanogaster FACT (dFACT) expressed in Sf9 cells. These sites are densely concentrated in the acidic intrinsically disordered (ID) region of the SSRP1 subunit and control nucleosomal DNA binding by dFACT. This region and the adjacent segment of the HMG domain form weak electrostatic intramolecular interactions, which is reinforced by the phosphorylation, thereby blocking DNA binding competitively. Importantly, this control mechanism appears to support rapid chromatin transactions during early embryogenesis through the dephosphorylation of some sites in the maternally transmitted dSSRP1.