Regulatory Pathways of SR Protein Kinases

项目概要/摘要： mRNA的剪接是一个复杂的生物学过程，它极大地增强了 细胞中有限的蛋白质编码基因组中的蛋白质多样性。虽然积分为 正常的功能，拼接错误可能会发生，并导致各种疾病，包括肌肉 营养不良、阿尔茨海默病、帕金森综合征、心血管疾病、共济失调和癌症。 剪接依赖于称为SR蛋白的基本因子，其结合前体mRNA， 选择性地掺入其他蛋白质/RNA元件，最终导致大分子 一种称为剪接体的机器，它执行某些非编码的必要切除 元素SRPKs是磷酸化和指导SR的蛋白激酶家族 蛋白质进入细胞核，在那里它们参与这些基本的剪接功能。虽然 关于SRPK在细胞质中的功能知道得很多，关于它们在细胞内的作用知之甚少。 原子核此外，尽管SRPKs最为人所知的是它们在剪接中的作用，但我们发现， 最近，SRPK 1磷酸化鱼精蛋白，从而调节鱼精蛋白到组蛋白 在受精时父方基因组的交换。我们将研究SRPK 1如何形成一个 与细胞核中的第二种蛋白激酶复合以激活磷酸化， 释放SR蛋白和用于剪接功能的U1 snRNP组分U1- 70 K。我们将 还探索SRPK 1如何使用一种新的识别机制相比，SR蛋白， 磷酸化鱼精蛋白并诱导DNA相变和基因组解凝聚 卵母细胞发育所必需的。这些研究将涉及广泛的生物物理 和生物技术，包括质谱、分子和细胞生物学、酶 动力学和共聚焦显微镜。总的来说，本提案中概述的实验将 解决蛋白激酶SRPK 1在控制蛋白质多样性中的关键功能 在生命的最早阶段。

Project Summary/Abstract: The splicing of mRNA is a complex biological process that enormously enhances the diversity of proteins within a limited set of protein-coding genes in the cell. While integral for normal function, errors in splicing can occur and lead to various diseases including muscular dystrophy, Alzheimer's disease, parkinsonism, cardiovascular disease, ataxias and cancers. Splicing relies on essential factors known as SR proteins that bind precursor mRNA and then selectively incorporate other protein/RNA elements ultimately leading to a macromolecular machine known as the spliceosome that performs the necessary excision of certain non-coding elements. The SRPKs are a family of protein kinases that phosphorylate and direct SR proteins to the nucleus where they participate in these essential splicing functions. Although much is known about SRPK function in the cytoplasm, less is known about their role in the nucleus. Furthermore, although SRPKs are best known for their role in splicing, we showed recently that SRPK1 phosphorylates protamines, thereby regulating protamine-to-histone exchange on the paternal genome upon fertilization. We will investigate how SRPK1 forms a complex with a second protein kinase in the nucleus to activate the phosphorylation and release of SR proteins and the U1 snRNP component U1-70K for splicing function. We will also explore how SRPK1 uses a novel recognition mechanism compared to SR proteins to phosphorylate protamines and induce DNA phase transitions and genomic decondensation necessary for oocyte development. These studies will involve a broad range of biophysical and biological techniques including mass spectrometry, molecular and cell biology, enzyme kinetics, and confocal microscopy. Overall, the experiments outlined in this proposal will address the key functions of the protein kinase SRPK1 in controlling protein diversity as well as at the earliest stages of life.