Prorenin processing by cathepsin B in vitro and in transfected cells
Prorenin processing by cathepsin B in vitro and in transfected cells
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DOI：
10.1016/s0014-5793(98)01672-x
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发表时间：
1999-01-22
期刊：
影响因子：
3.5
通讯作者：
Reudelhuber, TL
中科院分区：
文献类型：
--
作者：
Jutras, I;Reudelhuber, TL
在血管紧张素的产生中催化初始蛋白水解切割反应的Renin首先合成为酶原，即前肾素，并且需要蛋白水解去除氨基末端前片段才能在体内激活。根据某些组织分泌颗粒中与肾素共定位的报道及其在体外激活原肾素的能力，已提出溶酶体水解酶组织蛋白酶B是原肾素加工酶。在本研究中，扫描诱变用于确定氨基酸决定的位点选择性切割的人组织蛋白酶B在体外的原肾素。还使用AtT-20细胞中的共表达测定来测试组织蛋白酶B在细胞内切割人原肾素的能力。我们的研究结果表明，一个基本的赖氨酸残基在-2位置的切割位点是必需的组织蛋白酶B在体外切割的原肾素和原肾素本身的结构可能占适当的切割位点的选择。此外，虽然组织蛋白酶B似乎被正确地分选到溶酶体中，但该酶在转染的AtT-20细胞中表现出原肾素加工活性，这引起了加工事件发生的细胞定位的问题。(C)1999年欧洲生物化学学会联合会。
Renin, which catalyzes the initial proteolytic cleavage reaction in the production of angiotensins, is first synthesized as a zymogen, prorenin, and requires the proteolytic removal of an amino-terminal prosegment for activation in vivo. The lysosomal hydrolase cathepsin B has been proposed as a prorenin processing enzyme based on reports of its co-localization with renin in the secretory granules of certain tissues and its ability to activate prorenin in vitro. In the current study, scanning mutagenesis was used to identify the amino acids which determine the site selectivity of prorenin cleavage by human cathepsin B in vitro. Co-expression assays in AtT-20 cells were also used to test for the ability of cathepsin B to cleave human prorenin within cells. Our results suggest that a basic lysine residue at the -2 position from the cleavage site is required for cathepsin B cleavage of prorenin in vitro and that the structure of prorenin itself may account for the selection of the proper cleavage site. In addition, although cathepsin B appears to be correctly sorted to lysosomes, the enzyme exhibits prorenin processing activity in transfected AtT-20 cells, raising the question of the cellular localization in which the processing event occurs. (C) 1999 Federation of European Biochemical Societies.