Proteinase Inhbitors & Crystallin Fragments in Cataract

产品说明：在老化过程中，由于聚集和/或交联，增加比例的总透镜蛋白质变为水不溶性（W1）。这些物质进一步交联成共价多聚体被认为在年龄相关性（老年性）白内障发展期间引起不透明。晶体蛋白的各种翻译后修饰在文献中被描述为交联机制的致病因素，但它们的相对作用尚不清楚。由于老年性白内障的发展是一个缓慢的过程，有时需要数年，很少有特定的修改可能会作为触发器，加速交联机制，并导致透镜混浊。我们的研究结果表明，修饰的晶体蛋白片段在晶体蛋白交联过程中起着积极的作用。为了理解晶体蛋白片段的这种作用，必须确定它们的来源、翻译后修饰和交联机制，以便将它们作为致病因素。基于我们的结果，我们假设bA 3/A1 -晶状体蛋白具有蛋白酶活性，但活性在体内受到调节，因为酶活性需要活化，并且活性酶被α-晶状体蛋白抑制。bA 3/A1-晶状体蛋白酶蛋白水解a-、B-和g-晶状体蛋白，并且晶状体蛋白片段经历翻译后修饰，导致其本身交联以及与phakinin和filensin（透镜珠状丝蛋白）交联以形成共价多聚体。这些共价多聚体导致透镜不透明。为了验证上述假设，所提出的研究将集中于回答以下三个主要问题：（A）bA 3/ A1-晶状体蛋白的Arg键水解蛋白酶活性的激活的分子机制是什么？(B)体内B A3/A1-晶体蛋白酶活性是如何调节的？(C)什么是后结晶修饰晶体蛋白片段本身和与phakinin和filensin的共价交联机制？上述研究将为年龄相关性白内障发展过程中混浊如何发展这一核心问题提供答案。由于这些研究中将使用人类晶状体，因此这些发现将与阐明B A3/A1-晶状体蛋白酶在晶状体蛋白的蛋白水解中的作用、它们在体内的调节、特别是晶状体蛋白片段本身以及与phakinin和filensin交联的机制有关。

DESCRIPTION: During aging, an increasing proportion of total lens proteins becomes water insoluble (Wl), either due to aggregation and/or cross-linking. A further cross-linking of these species into covalent multimers is believed to cause opacity during age-related (senile) cataract development. A variety of post-translational modifications of crystallins are described in the literature as causative factors for cross-linking mechanism, but their relative roles remain unclear. Because the senile cataract development is a slow process and sometimes takes years, few specific modifications might act as triggers to accelerate the cross-linking mechanism and cause lens opacity. Our results show that modified crystallin fragments play an active role in the crystallin cross-linking process. To understand such a role of crystallin fragments, one must determine their origin, post-translational modifications and cross-linking mechanism in order to implicate them as a causative factor. Based on our results, we have hypothesized that bA3/A1 -crystallin contains proteinase activity, but the activity is regulated in vivo because the enzyme activity needed activation, and the active enzyme is inhibited by a-crystallin. The bA3/A1-crystallin proteinase proteolyses a-, b- and g-crystallins, and the crystallin fragments undergo post-translational modifications, leading to their cross-linking per se and with phakinin and filensin (lens beaded filament proteins) to form covalent multimers. These covalent multimers cause lens opacity. To test the above hypothesis, the proposed studies will be focused to answer the following three major questions: (A) What is the molecular mechanism of activation of an Arg-bond hydrolyzing proteinase activity of bA3/ A1-crystallin? (B) How is the b A3/A1-crystaltin proteinase activity regulated in vivo? (C) What is the covalent crosslinking mechanism of post-translationally modified crystallin fragments per se and with phakinin and filensin? The above studies will provide an answer to the central question of how opacity develops during age-related cataract development. Because human lenses will be used in these studies, the findings will be relevant in elucidating the role of b A3/A1-crystallin proteinase in the proteolysis of crystallins, their regulation in vivo, and in particular the mechanism of cross-linking of crystallin fragments per se and with phakinin and filensin.