CALCIUM ACTIVATED PROTEASE IN CATARACT FORMATION

这项资助的重点是提供一种详细的机制来控制晶状体中钙激活的钙蛋白酶家族的酶。这一点很重要，因为我们实验室的研究证实，过度的钙蛋白酶活性是导致各种啮齿动物白内障的基本机制，并且在几种动物老化的晶状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)钙蛋白在人类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表征的晶状体蛋白水解酶m-calain的功能和关系是什么？为了回答这些问题，我们将致力于以下几个方面的研究：1)确定晶状体特异性钙蛋白(Lp82)在晶状体中的功能和生化特性，以及它与先前研究过的晶状体m-calain的关系。2)研究不同钙蛋白酶缺陷对转基因小鼠晶状体发育和白内障发生的影响。3)确定钙调蛋白在人晶状体中的功能。这些实验将测试从非人类晶状体中获得的有关钙蛋白酶的积极数据是否适用于人类晶状体的情况，以及测试一种新发现的晶状体蛋白水解酶的作用。希望这些生化数据将有助于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.