Fission Yeast Mitotic Regulator Dsk1 Is an SR Protein-specific Kinase*
Fission Yeast Mitotic Regulator Dsk1 Is an SR Protein-specific Kinase*
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DOI：
10.1074/jbc.273.10.5963
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发表时间：
1998-03
期刊：
影响因子：
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通讯作者：
Zhaohua Tang;M. Yanagida;R. Lin
中科院分区：
文献类型：
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作者：
Zhaohua Tang;M. Yanagida;R. Lin
前体mRNA剪接和细胞分裂周期之间可能存在复杂的相互作用，裂变酵母Dsk 1似乎在这种连接中发挥作用。以前的遗传分析表明，Dsk 1在中期/后期过渡期的染色体分离的调节。然而，其蛋白质序列表明，Dsk 1可能作为一个激酶特异性SR蛋白，一个家庭的前mRNA剪接因子含有丝氨酸-丝氨酸重复。使用纯化的成分在体外系统，我们表明，DSK 1磷酸化的人和酵母SR蛋白具有高特异性。Dsk 1-磷酸化的SF 2/ASF蛋白被一种单克隆抗体（mAb 104）强烈地识别，该单克隆抗体已知结合SR蛋白所共有的体内磷酸化表位，这表明磷酸化位点位于RS结构域中。此外，裂殖酵母U2 AF 65同源物，Prp 2/Mis 11蛋白，磷酸化更有效地由Dsk 1比由人类SR蛋白特异性激酶，SRPK 1。因此，这些体外结果表明，Dsk 1是一个分裂酵母SR蛋白特异性激酶，Prp 2/Mis 11可能是Dsk 1的体内靶点。结合先前的遗传数据，这些研究支持Dsk 1可能在协调前mRNA剪接和细胞分裂周期中发挥作用的观点。
Intricate interplay may exist between pre-mRNA splicing and the cell division cycle, and fission yeast Dsk1 appears to play a role in such a connection. Previous genetic analyses have implicated Dsk1 in the regulation of chromosome segregation at the metaphase/anaphase transition. Yet, its protein sequence suggests that Dsk1 may function as a kinase specific for SR proteins, a family of pre-mRNA splicing factors containing arginine-serine repeats. Using an in vitro system with purified components, we showed that Dsk1 phosphorylated human and yeast SR proteins with high specificity. The Dsk1-phosphorylated SF2/ASF protein was recognized strongly by a monoclonal antibody (mAb104) known to bind the in vivo phosphoepitope shared by SR proteins, indicating that the phosphorylation sites resided in the RS domain. Moreover, the fission yeast U2AF65 homolog, Prp2/Mis11 protein, was phosphorylated more efficiently by Dsk1 than by a human SR protein-specific kinase, SRPK1. Thus, these in vitroresults suggest that Dsk1 is a fission yeast SR protein-specific kinase, and Prp2/Mis11 is likely an in vivo target for Dsk1. Together with previous genetic data, the studies support the notion that Dsk1 may play a role in coordinating pre-mRNA splicing and the cell division cycle.