Mechanism for the regulation of sperm flagellar motility by ubiquitin/proteasome system

泛素/蛋白酶体系统调节精子鞭毛运动的机制

基本信息

批准号：
12640660
负责人：
INABA Kazuo
金额：
$ 2.37万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Ubiquitin/proteasome system is involved in the degradation of short life-time proteins and the regulation of several important intracellular processes. It also plays important roles in the process of fertilization, such as sperm-egg interaction and the regulation of sperm motility. In this research several approach were conducted to reveal the mechanism for the regulation of sperm motility by this system, with salmonid fish and ascidian as experimental materials. First, apart from a dynein light chain which is closely related to sperm proteasome system, I have identified a novel 15 kDa protein of which phosphorylation is regulated by proteasome. The protein is shown to be located at the base of the flagellum. Second, the proteasome system is shown to be upstream regulated by membrane hyperpolarization exerted by a pottasium channel. Third, research was conducted to reveal if ubiquitinated proteins were present in broad range of organisms. It was shown that salmonid fish sperm contain no detectable ubiquitinated protein, however ascidian sperm show high content in ubiquitinated proteins. In ascidian sperm, ubiquitin is localized in the region between sperm nucleus and mitochondrion. These suggest that ubiquitin is involved not in the general aspect of sperm function such as sperm motility but in ascidian-specific process, most likely in mitochndrial discrimination observed at fertilization. Finally several genes for ubiquitin/ proteasome system have been isolated by overall anaysis of genes expressed in Ciona testis. The 12,000 ESTs so far analyzed contain several enzymes for protein ubiquitination and components of 26 S proteins. These cDNAs would surely provide a powerful tools for further research on the function of ubiquitin/ proteasome system in sperm cells.

泛素/蛋白酶体系统参与了短期蛋白质的降解以及几个重要的细胞内过程的调节。它在受精过程中也起着重要作用，例如精子相互作用和精子运动的调节。在这项研究中，采用了几种方法，以揭示该系统调节精子运动的机制，鲑鱼和海鞘作为实验材料。首先，除了与精子蛋白酶体系统密切相关的动力蛋白轻链外，我已经确定了一种新型的15 kDa蛋白，其中磷酸化受蛋白酶体调节。该蛋白质显示位于鞭毛的底部。其次，蛋白酶体系统被证明是由盆腔通道施加的膜超极化调节的上游。第三，进行了研究以揭示是否存在于广泛的生物体中是否存在泛素化蛋白。结果表明，鲑鱼鱼精子没有可检测到的泛素化蛋白，但是海囊的精子在泛素化蛋白中含量很高。在海囊的精子中，泛素位于精子核和线粒体之间的区域中。这些表明，泛素不参与精子功能的一般方面，例如精子运动，而是在海囊特异性过程中，最有可能在受精时观察到的线性散布。最后，已经通过在ciona睾丸中表达的基因的整体anaysis分离出了几种泛素/蛋白酶体系统的基因。到目前为止，分析的12,000个EST含有几种用于蛋白质泛素化的酶和26 s蛋白的成分。这些cDNA肯定会提供有力的工具，以进一步研究精子细胞中泛素/蛋白酶体系统的功能。