CALCIUM ACTIVATED PROTEASE IN CATARACT FORMATION

这项资助的重点是提供一个详细的机制，以控制钙蛋白酶家族的晶状体。这一点很重要，因为我们实验室的研究表明，钙蛋白酶活性过剩是导致多种啮齿类动物白内障的根本潜在机制，并且在几种动物的老化晶体中发现了钙蛋白酶裂解位点。然而，有两个主要问题需要解决：1)钙蛋白酶在人体晶状体中的作用是什么？2)新发现的晶状体特异性钙蛋白酶与先前鉴定的晶状体蛋白酶m-钙蛋白酶的功能和关系是什么？为了回答这些问题，将追求以下具体目标：1)确定晶状体中晶状体特异性calpain （Lp82）的功能和生化特性及其与先前表征的晶状体m-calpain的关系。2)确定不同钙蛋白酶缺乏对转基因小鼠晶状体发育和白内障发生的影响。3)确定晶状体钙蛋白的功能。这些实验将测试从非人类晶状体中获得的钙蛋白酶阳性数据对人类晶状体情况的适用性，以及测试新发现的晶状体蛋白酶的作用。希望这些生化数据将导致基于蛋白酶抑制剂的抗白内障药物的合理开发。

This grant is focused on providing a detailed mechanism for control of calcium activated proteases of the calpain family in lens. This is important because research from our laboratories established that excess calpain activity is the fundamental underlying mechanism causing a variety of rodent cataracts, and that calpain cleavage sites are found in aging lenses from several types of animals. However, two major questions need to be addressed: 1) What is the role of calpain in human lens? and 2) What is the function and relationship of the newly discovered lens-specific calpains to the previously characterized lens protease m-calpain? In order to answer these questions, these specific aims will be pursued: 1) Determine the function and biochemical properties of lens-specific calpain (Lp82) in lens and its relationship to previously characterized lens m-calpain. 2) Determine the effects of various calpain deficiencies on lens development and cataractogenesis in transgenic mice. 3) Determine the functions of calpains in human lens. These experiments will test the applicability of the positive data on calpain obtained from non-human lenses to the human lens situation, as well as testing the role of a newly discovered lens protease. The hope is that these biochemical data will lead to rational development of anticataract drugs based protease inhibitors.