Low activity by the calpain system in primate lenses causes resistance to calcium-induced proteolysis
Low activity by the calpain system in primate lenses causes resistance to calcium-induced proteolysis
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DOI：
10.1016/j.exer.2006.02.014
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发表时间：
2006-09-01
影响因子：
3.4
通讯作者：
Azuma, M.
中科院分区：
文献类型：
--
作者：
Nakajima, E.;Walkup, R. D.;Azuma, M.
人类基因组包含钙激活蛋白酶钙蛋白酶 (EC 34.22.17) 80 kDa 催化亚基的 14 个基因，但在体内人晶状体蛋白上尚未检测到钙蛋白酶样切割位点。本研究的目的是对由于离子载体 A23187 中的晶状体培养而导致实验性白内障的人类和猕猴晶状体中钙蛋白酶的激活进行全面研究。使用酶谱法测量钙蛋白酶活性；使用 SDS-PAGE 和免疫印迹来检测潜在晶状体蛋白底物的水解。定量 PCR 用于测量钙蛋白酶和内源性抑制剂钙蛋白酶抑制素的转录物。我们发现，灵长类动物晶状体中缺乏明显的钙蛋白酶诱导的蛋白水解很可能是由于与高水平的内源性钙蛋白酶抑制剂钙蛋白酶抑制素相比，内源性钙蛋白酶活性水平相对较低。 (c) 2006 Elsevier Ltd. 保留所有权利。
The human genome contains 14 genes for 80 kDa catalytic subunit of the calcium-activated protease calpain (EC 34.22.17), yet no calpain-like cleavage sites have been detected on human lens crystallins in vivo. The purpose of the present study was to provide a comprehensive study of calpain activation in human and macaque lenses developing experimental cataract due to lens culture in ionophore A23187. Zymography was used to measure calpain activity; SDS-PAGE and immunoblotting were used to detect hydrolysis of potential lens protein substrates. Quantitative PCR was used to measure transcripts for calpains and the endogenous inhibitor calpastatin. We found that the lack of appreciable calpain-induced proteolysis in primate lenses is most likely due to relatively low levels of endogenous calpain activity compared to the high levels of endogenous calpain inhibitor, calpastatin. (c) 2006 Elsevier Ltd. All rights reserved.