High mobility group protein-B1 interacts with sterol regulatory element-binding proteins to enhance their DNA binding
High mobility group protein-B1 interacts with sterol regulatory element-binding proteins to enhance their DNA binding
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DOI：
10.1074/jbc.m414549200
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发表时间：
2005-07-29
影响因子：
4.8
通讯作者：
Shimano, H
中科院分区：
文献类型：
--
作者：
Najima, Y;Yahagi, N;Shimano, H
甾醇调节元件结合蛋白（SREBPs）是主要参与脂肪生成和胆固醇生成酶基因表达调控的转录因子。为了鉴定与SREBP相互作用的未知蛋白，我们用s -35标记的SREBP-1诱饵在Far Western blotting分析中筛选核提取物蛋白。利用这种方法，高迁移率组蛋白- b1 （HMGB1）被鉴定为一种新的SREBP相互作用蛋白。体外谷胱甘肽s转移酶拉降和体内共免疫沉淀研究证实了HMGB1与SREBP-1和-2之间的相互作用。蛋白-蛋白相互作用通过SREBP-1的螺旋-环-螺旋结构域、309-344残基和HMGB1的A盒介导。此外，电泳迁移率转移实验表明，HMGB1增强了SREBPs与其同源DNA序列的结合。此外，包括RNA干扰技术在内的荧光素酶报告基因分析显示，HMGB1增强了培养细胞中SREBP的转录活性。这些发现提出了一种有趣的可能性，即HMGB1可能参与了脂肪生成和胆固醇生成基因转录的调节。
Sterol regulatory element-binding proteins (SREBPs) are transcription factors that are predominately involved in the regulation of lipogenic and cholesterogenic enzyme gene expression. To identify unknown proteins that interact with SREBP, we screened nuclear extract proteins with S-35-labeled SREBP-1 bait in Far Western blotting analysis. Using this approach, high mobility group protein-B1 (HMGB1), a chromosomal protein, was identified as a novel SREBP interacting protein. In vitro glutathione S-transferase pull-down and in vivo coimmunoprecipitation studies confirmed an interaction between HMGB1 and both SREBP-1 and -2. The protein-protein interaction was mediated through the helix-loop-helix domain of SREBP-1, residues 309-344, and the A box of HMGB1. Furthermore, an electrophoretic mobility shift assay demonstrated that HMGB1 enhances SREBPs binding to their cognate DNA sequences. Moreover, luciferase reporter analyses, including RNA interference technique showed that HMGB1 potentiates the transcriptional activities of SREBP in cultured cells. These findings raise the intriguing possibility that HMGB1 is potentially involved in the regulation of lipogenic and cholesterogenic gene transcription.