Cell Adhesion Molecules of Mammalian Fertilization

描述(申请人提供)：受精取决于精子和卵子的成功相互作用。从细胞生物学的角度来看，配子膜之间的相互作用是一个有趣的过程，从精子接触并附着到卵膜，发展到牢固的细胞-细胞黏附，最后到膜融合。我们对配子膜相互作用的分子机制的了解还很不完整。该项目的总体和长期目标是了解哺乳动物配子之间细胞黏附的机制和调节。参与哺乳动物配子膜相互作用的两种精子蛋白是ADAM(A DisIntegrin And A Metals Protease)家族的成员，即受精素α(Fertilinα，ADAM1)和受精素β(Fertilin beta，ADAM2)。我们对受精素β中与鸡蛋质膜相互作用的关键氨基酸的测定导致了卵子上潜在的受精素β结合伙伴的确定。这项提案的具体目标1将建立在这项工作的基础上，研究候选整合素与受精素β的相互作用，包括对缺乏β1整合素亚单位的鸡蛋的研究。我们对受精素a的研究表明，这种精子蛋白可以使用两个不同的结构域与卵膜相互作用。在此基础上，特殊目标2将确定这些受精蛋白α区域如何与卵膜相互作用，包括结构-功能分析和结合伙伴的鉴定。除了对特定分子相互作用的分析外，该项目还将研究精子-卵子通过这些配子分子和其他配子分子的协调功能发生粘连的机制。很明显，配子之间的相互作用是一个复杂的事件，可能由精子和卵子上的多个分子介导，并以循序渐进的方式发生。我们在其他细胞黏附系统的基础上提出了一个配子细胞黏附模型，其中多个分子参与，配子黏附分子的相互作用在精子和卵子之间形成牢固的黏附。具体目标3将测试这一模型的各个方面，包括研究卵细胞骨架和卵膜蛋白CD9在加强与精子亚当斯的粘连中的作用。这些研究的结果将应用于人类生殖健康，并对不孕不育和生育的管理产生影响。这项研究还将通过研究这一有趣的、具有生物学意义的细胞-细胞相互作用事件来解决细胞黏附生物学中的基本问题。

DESCRIPTION (provided by applicant): Fertilization depends on the successful interaction of the sperm with the egg. The interactions between the gamete membranes is a fascinating process from a cell biological standpoint, beginning with the sperm contacting and attaching to the egg membrane, progressing to firm cell-cell adhesion, and culminating in membrane fusion. Our understanding of the molecular mechanisms underlying gamete membrane interactions is still very incomplete. The overall, long term goal of this project is to understand the mechanism and regulation of cell adhesion between mammalian gametes. Two sperm proteins that participate in mammalian gamete membrane interactions are members the ADAM (A Disintegrin and A Metalloprotease) family of proteins, fertilin alpha (ADAM1) and fertilin beta (ADAM2). Our determination of the key amino acids in fertilin beta that interact with the egg plasma membrane has led to the identification of potential fertilin beta binding partners on eggs. Specific Aim 1 of this proposal will build on this work with investigation of the interactions of candidate integrins with fertilin beta, including studies of eggs deficient in the beta1 integrin subunit. Our studies of fertilin a indicate that this sperm protein can use two different domains to interact with the egg membrane. Following up on this, Specific Aim 2 will determine how these domains of fertilin alpha interact with the egg membrane, including structure-function analysis and identification of binding partners. In addition to this analysis of specific molecular interactions, this project also will examine the mechanism by which sperm-egg adhesion occurs via the coordinated function of these and other gamete molecules. It has become clear that the interaction between the gametes is a complex event, likely to be mediated by multiple molecules on the sperm and egg and to occur in a step-wise fashion. We propose a model for gamete cell adhesion, based on other cell adhesion systems, in which multiple molecules participate and the interactions of gamete adhesion molecules progress to form firm adhesions between the sperm and egg. Specific Aim 3 will test aspects of this model, including studies of the roles of the egg cytoskeleton and the egg membrane protein CD9 in the strengthening of adhesions to sperm ADAMs. Results of these studies will have applications to human reproductive health, with implications for the management of infertility and fertility. This research also will also address fundamental questions in cell adhesion biology by examining this interesting, biologically relevant cell-cell interaction event.