D4476, a cell-permeant inhibitor of CK1, suppresses the site-specific phosphorylation and nuclear exclusion of FOXO1a
D4476, a cell-permeant inhibitor of CK1, suppresses the site-specific phosphorylation and nuclear exclusion of FOXO1a
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DOI：
10.1038/sj.embor.7400048
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发表时间：
2004-01-01
期刊：
影响因子：
7.7
通讯作者：
Cohen, P
中科院分区：
文献类型：
--
作者：
Rena, G;Bain, J;Cohen, P
蛋白激酶CK1磷酸化的丝氨酸残基与pSer-Xaa-Xaa-Ser序列中的另一个丝氨酸残基接近。这种特异性在其靶蛋白中产生含有两个或多个相邻丝氨酸残基的区域，这里称为多位点磷酸化结构域（MPDs）。在本文中，我们证明了D4476在体外和细胞中是一种有效的、选择性的CK1抑制剂。在H4IIE肝癌细胞中，D4476特异性抑制其MPD内内源性叉头盒转录因子O1a （FOXO1a）在Ser322和Ser325上的磷酸化，而不影响其他位点的磷酸化。我们的研究结果表明，这些残基在体内被CK1靶向，并且CK1介导的MPD磷酸化是在IGF-1和胰岛素反应中加速FOXO1a核排斥所必需的。D4476比IC261或CKI-7更有效和特异，因此是目前可用来鉴定CK1生理底物的最有用的CK1抑制剂。
The protein kinase CK1 phosphorylates serine residues that are located close to another phosphoserine in the consensus pSer-Xaa-Xaa-Ser. This specificity generates regions in its target proteins containing two or more neighbouring phosphoserine residues, termed here multisite phosphorylation domains (MPDs). In this paper, we demonstrate that D4476 is a potent and rather selective inhibitor of CK1 in vitro and in cells. In H4IIE hepatoma cells, D4476 specifically inhibits the phosphorylation of endogenous forkhead box transcription factor O1a (FOXO1a) on Ser322 and Ser325 within its MPD, without affecting the phosphorylation of other sites. Our results indicate that these residues are targeted by CK1 in vivo and that the CK1-mediated phosphorylation of the MPD is required for accelerated nuclear exclusion of FOXO1a in response to IGF-1 and insulin. D4476 is much more potent and specific than IC261 or CKI-7, and is therefore the most useful CK1 inhibitor currently available for identifying physiological substrates of CK1.