Activation of Pre-mRNA Splicing by Human RNPS1 Is Regulated by CK2 Phosphorylation
Activation of Pre-mRNA Splicing by Human RNPS1 Is Regulated by CK2 Phosphorylation
复制标题
DOI：
10.1128/mcb.25.4.1446-1457.2005
复制
发表时间：
2005-02
影响因子：
5.3
通讯作者：
J. Trembley;S. Tatsumi;E. Sakashita;P. Loyer;C. Slaughter;H. Suzuki;H. Endo;V. Kidd;A. Mayeda
中科院分区：
文献类型：
--
作者：
J. Trembley;S. Tatsumi;E. Sakashita;P. Loyer;C. Slaughter;H. Suzuki;H. Endo;V. Kidd;A. Mayeda
摘要人RNPS 1最初在体外被鉴定为前体mRNA剪接激活剂，并被证明在体内调节选择性剪接。RNPS 1也被鉴定为剪接依赖性mRNP复合物或外显子-外显子连接复合物（EJC）的蛋白质组分，并提出了RNPS 1在剪接后过程中的作用。在这里，我们证明RNPS 1纳入到活跃的spliceosomes，增强ATP依赖的A复合物的形成，并促进中间和最终剪接产物的产生。RNPS 1在体内被磷酸化，并与CK 2（酪蛋白激酶II）蛋白激酶相互作用。RNPS 1的丝氨酸53（Ser-53）被鉴定为CK 2在体外的主要磷酸化位点，并且同一位点在体内也被磷酸化。Ser-53的磷酸化状态显著影响体外剪接激活，但它不会干扰RNPS 1的核定位。体内实验表明RNPS 1在Ser-53的磷酸化影响剪接和翻译的效率。我们认为RNPS 1是一种剪接调节因子，其激活功能部分受CK 2磷酸化控制。
ABSTRACT Human RNPS1 was originally characterized as a pre-mRNA splicing activator in vitro and was shown to regulate alternative splicing in vivo. RNPS1 was also identified as a protein component of the splicing-dependent mRNP complex, or exon-exon junction complex (EJC), and a role for RNPS1 in postsplicing processes has been proposed. Here we demonstrate that RNPS1 incorporates into active spliceosomes, enhances the formation of the ATP-dependent A complex, and promotes the generation of both intermediate and final spliced products. RNPS1 is phosphorylated in vivo and interacts with the CK2 (casein kinase II) protein kinase. Serine 53 (Ser-53) of RNPS1 was identified as the major phosphorylation site for CK2 in vitro, and the same site is also phosphorylated in vivo. The phosphorylation status of Ser-53 significantly affects splicing activation in vitro, but it does not perturb the nuclear localization of RNPS1. In vivo experiments indicated that the phosphorylation of RNPS1 at Ser-53 influences the efficiencies of both splicing and translation. We propose that RNPS1 is a splicing regulator whose activator function is controlled in part by CK2 phosphorylation.