The CRES Gene in Reproduction

描述（由申请人提供）：我们研究的长期目标是确定CRES （Cystatin-Related Epididymal Spermatogenic）蛋白在附睾精子成熟和精子功能中的作用。我们已经确定，CRES在半胱氨酸蛋白酶抑制剂胱抑素超家族2胱抑素家族中定义了一个新的亚群。虽然预测在结构上与原型家族的两种胱抑素相似，但我们最近证明了CRES不作为典型的胱抑素起作用。我们确定CRES不抑制半胱氨酸蛋白酶，而是丝氨酸蛋白酶激素原转化酶2 （PC2）的竞争性抑制剂（Ki = 25 nM）。由于PC2是一个在原激素和原蛋白的蛋白水解成熟中起关键作用的蛋白酶家族的成员，我们提出CRES可能是一种新的转化酶抑制剂，介导对生殖功能重要的蛋白水解加工事件。我的短期目标是确定CRES是否与体内PC2或其他转化酶相互作用，以及更详细地检查CRES作为转化酶抑制剂，并特别检查其对细胞中蛋白加工的影响。其他短期目标是研究CRES在体内的生物学作用，包括其在精子顶体和受精中的功能。我的长期目标是帮助我们理解原蛋白是如何被激活为成熟的功能形式的，特别是在精子和附睾中，以及这些过程被调节的机制。最终，这可能为男性避孕药具的发展提供目标机制。如果获得RCDA，将帮助我实现我的目标。具体来说，它将使我从包括医学院大体解剖的大量教学在内的部门义务中解脱出来，从而使我能够全身心地投入到研究中。此外，有了这个奖项，我将不需要在机构和部门层面的其他委员会任职。细胞生物与生物化学系为我的研究生涯提供了良好的发展环境。该系内有一大群由美国国立卫生研究院资助的生殖生物学家，他们提供专业知识和学院式的互动工作环境。此外，新购买的质谱仪将使上述研究的现场蛋白质分析成为可能。总之，TTUHSC的环境是特殊的，将完全支持我的研究计划。

DESCRIPTION (provided by applicant): The long-term objective of our research is to determine the role of the CRES (Cystatin-Related Epididymal Spermatogenic) protein in epididymal sperm maturation and sperm function. We have established that CRES defines a new subgroup in the family two cystatins of the cystatin superfamily of cysteine protease inhibitors. Although predicted to structurally resemble the archetype family two cystatins, we have recently demonstrated that CRES does not function as a typical cystatin. We determined that CRES does not inhibit cysteine proteases but rather is a competitive inhibitor (Ki = 25 nM) of the serine protease prohormone convertase 2 (PC2). Because PC2 is a member of a family of proteases with critical roles in the proteolytic maturation of prohormones and proproteins, we propose that CRES may be a new convertase inhibitor that mediates proteolytic processing events important for reproductive function. My short-term goals are to establish whether CRES interacts with PC2 or other convertases in vivo as well as to examine CRES as a convertase inhibitor in greater detail and specifically examine its effects on proprotein processing in cells. Other short-term goals are to examine the biological roles of CRES in vivo including its function in the sperm acrosome and fertilization. My long-term goals are to contribute to our understanding of how proproteins are activated to their mature and functional forms, specifically within spermatozoa and the epididymis, and the mechanisms by which these processes are regulated. Ultimately this may provide mechanisms to target for male contraceptive development. The RCDA, if awarded, will assist me in accomplishing my goals. Specifically, it will release me from Departmental obligations including substantial teaching in medical school gross anatomy, thereby allowing me to devote my full attention to research. In addition, with this award I will not be required to serve on additional committees both at the institutional and departmental levels. The Department of Cell Biology and Biochemistry provides a supportive environment for the development of my research career. Within the department is a large group of NIH-funded reproductive biologists who provide expertise and a collegial, interactive working environment. Also, the newly purchased mass spec will enable on site protein analysis for the studies described above. In short, the environment at TTUHSC is exceptional and will fully support my proposed studies.