Two isoforms of the protein kinase pUL97 of human cytomegalovirus are differentially regulated in their nuclear translocation.
Two isoforms of the protein kinase pUL97 of human cytomegalovirus are differentially regulated in their nuclear translocation.
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人巨细胞病毒蛋白激酶 pUL97 的两种亚型在核易位方面受到差异性调节。
DOI：
10.1099/vir.0.026799-0
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M. Marschall
中科院分区：
文献类型：
--
作者：
Rike Webel;Jens Milbradt;S. Auerochs;V. Schregel;C. Held;Katharina Nöbauer;E. Razzazi;Christophe Jardin;T. Wittenberg;H. Sticht;M. Marschall
由人巨细胞病毒编码的pUL 97蛋白激酶是病毒复制效率的多功能决定因素，并使病毒和细胞底物蛋白磷酸化。在这里，我们报告说，pUL 97表达在两个异构体的分子量约为90和100 kDa。ORF UL 97包含一种不寻常的编码策略，即在N-末端157个氨基酸内含有5个框内ATG起始密码子。定点诱变，瞬时表达的点和缺失突变体和蛋白质组学分析积累的证据表明，形成的大和小的异构体的翻译结果从替代启动，与起始点分别在氨基酸1和74。在体外激酶试验表明，催化活性，在自磷酸化和组蛋白底物磷酸化，是不可区分的两种亚型。通过共聚焦激光扫描显微镜对pUL 97的细胞内分布的分析表明，这两种亚型具有明显的核定位。令人惊讶的是，为鉴定pUL 97的核定位信号（NLS）而进行的绘图实验强烈表明，这两种亚型的核转运机制是不同的。虽然末端N末端（大同种型）包含高效的二分NLS（氨基酸6-35），但在氨基酸74（小和大同种型）下游鉴定出明显赋予较低效率的核易位模式的第二序列。综上所述，研究结果表明pUL 97的核转位机制复杂，可能与两种亚型之间的精细调控差异有关。
The pUL97 protein kinase encoded by human cytomegalovirus is a multifunctional determinant of the efficiency of viral replication and phosphorylates viral as well as cellular substrate proteins. Here, we report that pUL97 is expressed in two isoforms with molecular masses of approximately 90 and 100 kDa. ORF UL97 comprises an unusual coding strategy in that five in-frame ATG start codons are contained within the N-terminal 157 aa. Site-directed mutagenesis, transient expression of point and deletion mutants and proteomic analyses accumulated evidence that the formation of the large and small isoforms result from alternative initiation of translation, with the start points being at amino acids 1 and 74, respectively. In vitro kinase assays demonstrated that catalytic activity, in terms of autophosphorylation and histone substrate phosphorylation, was indistinguishable for the two isoforms. An analysis of the intracellular distribution of pUL97 by confocal laser-scanning microscopy demonstrated that both isoforms have a pronounced nuclear localization. Surprisingly, mapping experiments performed to identify the nuclear localization signal (NLS) of pUL97 strongly suggest that the mechanism of nuclear transport is distinct for the two isoforms. While the extreme N terminus (large isoform) comprises a highly efficient, bipartite NLS (amino acids 6-35), a second sequence apparently conferring a less efficient mode of nuclear translocation was identified downstream of amino acid 74 (small and large isoforms). Taken together, the findings argue for a complex mechanism of nuclear translocation for pUL97 which might be linked with fine-regulatory differences between the two isoforms.
DOI：
10.1073/pnas.98.4.1895
发表时间：
2001-02
影响因子：
11.1
作者：
D. Wolf;C. T. Courcelle;M. Prichard;E. Mocarski
通讯作者：
D. Wolf;C. T. Courcelle;M. Prichard;E. Mocarski
影响因子：
3.8
作者：
Becke, Sabine;Fabre-Mersseman, Veronique;Reyda, Sabine
通讯作者：
Reyda, Sabine