Phosphoinositide signaling and sperm fertility

描述(申请人提供)：哺乳动物精子以静止和不育的状态储存在男性生殖道中。只有在雌性生殖道内孵化时，才有能力到达受精地点并成功地与卵子相互作用。导致精子功能成熟的分子变化统称为获能。这些过程对于繁殖是必不可少的。因此，获能的生理调节机制可能为避孕干预提供新的靶点。精子膜上的多聚磷酸肌醇在获能和精子-卵子相互作用的关键步骤中起中介作用。然而，人们对调节这些磷脂酰肌醇水平的脂蛋白激酶和磷酸酶知之甚少。在这里，我们关注的是3‘-磷脂酰肌醇磷酸酶，TPTE。正如将要讨论的，TPTE转录本只在生精细胞中被检测到，并且预期的酶活性表明在获能中起作用。此外，提供的初步数据显示，小鼠附睾尾精子的前头和鞭毛中含有具有酶活性的Tpte蛋白。然而，由于缺乏试剂，我们没有关于这种蛋白质在精子中的作用的直接信息。在这项探索性研究中，我们将建立一个Tpte基因突变且缺乏磷酸酶活性的小鼠系，并检测这些小鼠的生殖表型。此外，我们还将开始分析TPTE磷酸酶的催化活性。这项探索性研究代表了一项长期努力的第一阶段，目的是确定TPTE以及其他磷酸肌醇激酶和磷酸酶在精子功能和生殖中的作用。 公共卫生相关性：该项目的重点是控制精子受精率。因此，它直接涉及两个与健康相关的问题。首先，在美国，10%-15%的夫妇会受到不孕症的影响，这项研究可能会带来治疗这种疾病的新方法。其次，据估计，全球人口目前已超过67亿。这个项目研究了一种精子特异性脂质磷酸酶，它将为避孕干预提供一个新的靶点。在这里进行的实验将确定这种磷酸酶在精子受精率中的作用，并开始表征磷酸酶的活性。

DESCRIPTION (provided by applicant): Mammalian sperm are stored in the male reproductive tract in an immotile and infertile state. The ability to reach the site of fertilization and to interact with eggs successfully is only developed during incubation within the female reproductive tract. The molecular alterations in sperm that account for this functional maturation are, collectively, known as capacitation. These processes are essential for reproduction. As such, the physiological regulators of capacitation may provide novel targets for contraceptive intervention. Polyphosphorylated phosphoinositides in the sperm membrane mediate key steps in capacitation and sperm-egg interaction. However, little is known about the lipid kinases and phosphatases that regulate the levels of these phosphoinositides. Here, we focus on the 3'-phosphoinositide phosphatase, Tpte. As will be discussed, Tpte transcripts are detected only in spermatogenic cells and the anticipated enzymatic activity suggests a role in capacitation. In addition, preliminary data is presented showing that cauda epididymal mouse sperm contain enzymatically-active Tpte protein in the anterior head and in the flagellum. However, we have no direct information regarding the role of this protein in sperm due to a lack of reagents. In this exploratory study we will generate a mouse line in which the Tpte locus is mutated and lacking phosphatase activity, and examine the reproductive phenotype of these mice. In addition we will begin an analysis of the catalytic activity of Tpte phosphatase activity. This exploratory study represents the first stage of a long-term effort to determine the role of Tpte, as well as other phosphoinositide kinases and phosphatases, in sperm function and reproduction. PUBLIC HEALTH RELEVANCE: This project focuses on the control of sperm fertility. As such, it directly relates to two issues of health relevance. First, episodes of infertility affect 10-15% of couples in the US and this work may lead to new treatments for this condition. Second, population is now estimated to exceed 6,700 million world-wide. This project examines a sperm-specific lipid phosphatase that would provide a novel target for contraceptive intervention. The experiments carried out here will determine the role of this phosphatase in sperm fertility and begin characterization of phosphatase activity.