Different requirements of the kinase and UHM domains of KIS for its nuclear localization and binding to splicing factors
Different requirements of the kinase and UHM domains of KIS for its nuclear localization and binding to splicing factors
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DOI：
10.1016/j.jmb.2008.06.026
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发表时间：
2008-09-05
影响因子：
5.6
通讯作者：
Maucuer, Alexandre
中科院分区：
文献类型：
--
作者：
Manceau, Valerie;Kielkopf, Clara L.;Maucuer, Alexandre
蛋白激酶KIS是由一个独特的激酶结构域和一个具有U2 AF同源基序（UHM）的C-末端结构域并置而成，U2 AF同源基序是一种最初在异源二聚体前mRNA剪接因子U2 AE中鉴定的蛋白质相互作用的序列基序。KIS的该结构域与U2 AF大亚基U2 AF的C-末端UHM结构域密切相关（65）。KIS磷酸化剪接因子SF 1，进而增强SF 1与U2 AF（65）和3'剪接位点的结合，这是已知发生在剪接体组装早期的事件。在这里，突变形式的KIS的亚细胞定位的分析表明，KIS的激酶结构域是其核定位的必要结构域。与U2 AF（65）的情况一样，KIS的含UHM的C端结构域是与剪接因子SF 1和SF 3b结合所必需的155。在下拉试验中，KIS与SF 1和SF 3b 155的结合效率与U2 AF（65）相似。这些结果进一步支持KIS与剪接因子的功能联系。有趣的是，当与其他含有UHM的蛋白质相比时，KIS对SF 3b 155的N-末端区域中存在的UHM对接位点呈现出不同的特异性，从而为UHM结构域介导的各种相互作用提供了新的见解。(C)2008爱思唯尔有限公司保留所有权利。
The protein kinase KIS is made by the juxtaposition of a unique kinase domain and a C-terminal domain with a U2AF homology motif (UHM), a sequence motif for protein interaction initially identified in the heterodimeric pre-mRNA splicing factor U2AE This domain of KIS is closely related to the C-terminal UHM domain of the U2AF large subunit, U2AF(65). KIS phosphorylates the splicing factor SF1, which in turn enhances SF1 binding to U2AF(65) and the 3' splice site, an event known to take place at an early step of spliceosome assembly. Here, the analysis of the subcellular localization of mutated forms of KIS indicates that the kinase domain of KIS is the necessary domain for its nuclear localization. As in the case of U2AF(65), the UHM-containing C-terminal domain of KIS is required for binding to the splicing factors SF1 and SF3b155. The efficiency of KIS binding to SF1 and SF3b155 is similar to that of U2AF(65) in pull-down assays. These results further support the functional link of KIS with splicing factors. Interestingly, when compared to other UHM-containing proteins, KIS presents a different specificity for the UHM docking sites that are present in the N-terminal region of SF3b155, thus providing a new insight into the variety of interactions mediated by UHM domains. (C) 2008 Elsevier Ltd. All rights reserved.