Regulatory Pathways of SR Protein Kinases

项目概要/摘要： 剪接将单个基因转化为多个独特的mRNA片段，以扩增多个mRNA片段。 蛋白质组的大小和调节细胞功能。虽然拼接是不可或缺的正常功能， 在复杂的生物体中，剪接选择的错误会导致疾病。事实上，拼接错误 与许多人类疾病有关，包括肌肉萎缩症，阿尔茨海默氏症， 疾病、帕金森综合征、心血管疾病、共济失调和癌症。剪接发生在 剪接体是一种包括RNA和蛋白质的大分子复合物。在后一 SR蛋白是控制剪接体组装位置的重要剪接因子 前体mRNA上。SR蛋白含有富含丝氨酸-丝氨酸重复序列的C端结构域 其多磷酸化控制剪接位点选择。SRPK蛋白激酶家族 磷酸化这些RS结构域，引导SR蛋白进入细胞核进行剪接活性。 虽然SRPKs通常定位于细胞质以实现这一功能，但它们可以进入细胞内。 细胞核在一定条件下，但他们的功能，在这个细胞隔室是不好的 明白我们现在将研究SRPKs在细胞质中的功能， 细胞核全基因组剪接分析，细胞成像，快速混合动力学，蛋白酶 足迹和结构技术。我们将确定唯一的SRPK 磷酸化机制控制SR蛋白从细胞质转运到 原子核我们将探索通过一种新的激酶调节SRPK核输入的因素- 激酶复合物最后，我们将研究这种复合物如何影响剪接反应， SR蛋白在细胞核中的移动。总体而言，本提案中概述的研究将 大大扩展了我们对SRPK诱导的SR蛋白磷酸化及其 拼接功能

Project Summary/Abstract: Splicing converts a single gene into multiple unique mRNA fragments to expand the size of the proteome and regulate cell function. While splicing is integral for normal function in complex organisms, mistakes in splice-selection can lead to disease. In fact, splicing errors are associated with numerous human disorders including muscular dystrophy, Alzheimer's disease, parkinsonism, cardiovascular disease, ataxias and cancers. Splicing occurs at the spliceosome, a macromolecular complex that includes both RNA and protein. In the latter group, SR proteins are essential splicing factors that control where the spliceosome assembles on precursor mRNA. SR proteins contain C-terminal domains rich in arginine-serine repeats whose polyphosphorylation controls splice-site selection. The SRPK family of protein kinases phosphorylates these RS domains directing SR proteins into the nucleus for splicing activity. While SRPKs are normally localized to the cytoplasm for this function, they can enter the nucleus under certain conditions but their function in this cellular compartment is not well understood. We will now investigate the functions of SRPKs in both the cytoplasm and nucleus using genome-wide splicing assays, cell imaging, fast-mixing kinetics, protease footprinting and structural techniques. We will determine how the unique SRPK phosphorylation mechanism governs transport of SR proteins from the cytoplasm to the nucleus. We will explore factors that regulate SRPK nuclear import through a novel kinase- kinase complex. Finally, we will investigate how this complex affects splicing reactions through the mobilization of SR proteins in the nucleus. Overall, the studies outlined in this proposal will greatly expand our knowledge of SRPK-induced phosphorylation of SR proteins and their splicing function.