Protein Kinase A Anchoring in Spermatozoan Function

描述：(申请人提供)cAMP依赖的蛋白激酶(PKA)是 通过与A的相互作用靶向特定的亚细胞隔室 激酶锚定蛋白(AKAP)。膜透性多肽，设计用于 破坏PKA/AKAP相互作用，抑制精子活力，提示PKA锚定 是维持运动能力所必需的。这项提案的总体目标是 是研究精子AKAP与第二类调控蛋白的相互作用 PKA亚单位(RII)和RII-同系物，并确定这些相互作用是如何 调节精子功能(S)。我们将重点关注两个精子AKAP。AKAP110是 一种占主导地位的精子AKAP，也是我们之前提案的重点。径向辐条 蛋白3(Protein 3，RSP3)是衣藻中新发现的一种AKAP。这是第一次 在轴丝中发现鞭毛AKAP。这种蛋白质的突变会破坏 鞭毛跳动。我们最近已经鉴定、克隆并表达了人 这种蛋白质的同源物。根据这一AKAP的位置，我们假设 RSP3通过协调激酶和/或 轴丝中的磷酸酶。我们最近鉴定出了四种精子特异性 除PKA外，还有与精子AKAP110相互作用的人类蛋白质。所有的 这些蛋白质与AKAP对接和AKAP对接具有很强的序列相似性 RII的二聚化结构域。尽管这些精子蛋白似乎是 RII的功能同系物在结合AKAP的能力方面，它们没有共享 RII的其他功能，如结合cAMP或催化的能力 PKA亚基。其中两个RII同源基因似乎是RHO的一部分 信号通路。其中一种与小鼠罗布菌素同源。Ropporin被发现 沿着鞭毛的主要部分并与嗜血杆菌亲和素结合，一个靶标 Rho的蛋白质。第二种蛋白质名为AKAP相关精子蛋白(ASP)， 与罗布林有39%的同源性。抑制Rho信号转导的药物 抑制精子运动。这项提议的一个目标是检验这一假设 Rho信号通过与此类似的机制调节精子活力 在平滑肌中观察到的，精子AKAP通过 充当脚手架分子。本提案中概述的研究应 促进设计新的和高度特异的药理试剂 体内抑制精子功能。从这些研究中获得的知识也可能 有助于精子缺陷患者的诊断和治疗 运动和生育能力。

DESCRIPTION: (provided by applicant) The cAMP-dependent protein kinase (PKA) is targeted to specific subcellular compartments through its interaction with A kinase anchoring proteins (AKAPs). Membrane permeable peptides, designed to disrupt PKA/AKAP interaction, inhibit sperm motility, suggesting PKA anchoring is required for the maintenance of motility. The overall goal of this proposal is to characterize the interaction of sperm AKAPs with the type two regulatory subunit of PKA (RII) and RII-homologues, and determine how these interactions regulate spermatozoan function(s). We will focus on two sperm AKAPs. AKAP110 is a predominant sperm AKAP and the focus of our previous proposal. Radial Spoke Protein 3 (RSP3) is a newly discovered AKAP in Chlamydomonas. It is the first flagellar AKAP to be found in the axoneme. Mutation of this protein disrupts flagellar beating. We have recently identified, cloned and expressed the human homolog of this protein. Based on the location of this AKAP, we hypothesize that RSP3 regulates motility by coordinating the action of kinases and/or phosphatases in the axoneme. We have recently identified four sperm-specific human proteins, in addition to PKA, which interact with sperm AKAP110. All of these proteins have a strong sequence similarity to the AKAP docking and dimerization domains of RII. Although these sperm proteins appear to be functional homologues of RII in their ability to bind AKAPs, they do not share other functions of RII such as the ability to bind cAMP or the catalytic subunit of PKA. Two of these RII homologues appear to be part of the Rho signaling pathway. One is homologous to murine ropporin. Ropporin is found along the principal piece of the flagellum and binds to rhophilin, a target protein for Rho. A second protein, named AKAP-associated sperm protein (ASP), is 39 percent identical with ropporin. Agents that inhibit Rho signaling inhibit sperm motility. One goal of this proposal is to test the hypothesis that Rho signaling regulates sperm motility via a mechanism similar to that observed in smooth muscle and that sperm AKAPs coordinate this mechanism by acting as scaffolding molecules. Studies outlined in this proposal should facilitate the design of new and highly specific pharmacological reagents for inhibiting sperm function in vivo. Knowledge gained from these studies may also be useful for the diagnosis and treatment of patients with defects in sperm movement and fertility.