Identification of heterochromatin protein 1 (HP1) as a phosphorylation target by Pim-1 kinase and the effect of phosphorylation on the transcriptional repression function of HP1
Identification of heterochromatin protein 1 (HP1) as a phosphorylation target by Pim-1 kinase and the effect of phosphorylation on the transcriptional repression function of HP1
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DOI：
10.1016/s0014-5793(00)01105-4
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发表时间：
2000-02-04
期刊：
影响因子：
3.5
通讯作者：
Iguchi-Ariga, SMM
中科院分区：
文献类型：
--
作者：
Koike, N;Maita, H;Iguchi-Ariga, SMM
Pim-1是一种原癌基因产物，是一种丝氨酸/苏氨酸激酶，被认为在血细胞的信号转导中起作用。然而，很少有磷酸化的Pim-1的靶蛋白已被确定。在本研究中，进行双杂交筛选以克隆编码与Pim-1结合的蛋白质的cDNA，并获得异染色质蛋白1 y（HP 1 gamma）的cDNA。使用纯化的HP 1 γ和在大肠杆菌中表达的Pim-1在酵母中和体外下拉的结合测定表明，Pim-1直接结合到HP 1 γ的Chrome阴影结构域。在人HeLa细胞中，HP 1 γ也与Pim-1相关，并且位于HP 1 γ中心的丝氨酸簇在体外被Pim-1磷酸化。此外，通过Pim-1靶向的丝氨酸簇的缺失进一步刺激了HP 1 γ的转录抑制活性。这些结果表明，Pim-1通过磷酸化HP 1来影响染色质的结构或沉默。(C)2000年欧洲生物化学学会联合会。
Pim-1, a protooncogene product, is a serine/threonine kinase and is thought to play a role in signal transduction in blood cells. Few phosphorylated target proteins for Pim-1 however, have been identified. In the present study, two-hybrid screening to clone cDNAs encoding proteins binding to Pim-1 was carried out, and a cDNA for heterochromatin protein 1y (HP1 gamma) was obtained. Binding assays both in yeast and in vitro pull-down using the purified HP1 gamma and Pim-1 expressed in Escherichia coli showed that Pim-1 directly bound to the chrome shadow domain of HP1 gamma. HP1 gamma was also associated with Pim-1 in human HeLa cells and the serine clusters located at the center of HP1 gamma mere phosphorylated by Pim-1 in vitro. Furthermore, a transcription repression activity of HP1 gamma was further stimulated by the deletion of the serine clusters targeted by Pim-1, These results suggest that Pim-1 affects the structure or silencing of chromatin by phosphorylating HP1. (C) 2000 Federation of European Biochemical Societies.