The asp-rich region at the carboxyl-terminus of calsequestrin binds to Ca2+ and interacts with triadin
The asp-rich region at the carboxyl-terminus of calsequestrin binds to Ca2+ and interacts with triadin
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DOI：
10.1016/s0014-5793(00)02246-8
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发表时间：
2000-12-08
期刊：
影响因子：
3.5
通讯作者：
Kim, DH
中科院分区：
文献类型：
--
作者：
Shin, DW;Ma, JJ;Kim, DH
钙调蛋白(CSQ)是横纹肌连接肌浆网中一种高容量的钙离子结合蛋白，已被证明通过Triadin和Junctin来调节Ryanodine受体(RyR)。为了确定CSQ中特定区域的功能作用，通过分子克隆和大肠杆菌表达，制备了几个CSQ缺失突变体。利用天然凝胶体系进行的Ca-45(2+)重叠分析表明，CSQ的主要钙结合基序位于富含天冬氨酸的区域(氨基酸354-367)。在谷胱甘肽-S-转移酶亲和层析柱的体外结合实验中，发现CSQ与Triadin的相互作用是钙依赖的，并且相互作用的部位局限于CSQ的富含天冬氨酸的区域。我们的结果表明，CSQ富含天冬氨酸的区域可能通过提供一个与鲁米那钙和Triadin直接结合的部位，参与RyR介导的钙释放过程。(C)2000年欧洲生化学会联合会。爱思唯尔科学公司出版。版权所有。
Calsequestrin (CSQ) is a high capacity Ca2+ binding protein in the junctional sarcoplasmic reticulum of striated muscles, and has been shown to regulate the ryanodine receptor (RyR) through triadin and junctin. In order to identify the functional roles of specific regions on CSQ, several CSQ deletion mutants were prepared by molecular cloning and Escherichia coli expression. Ca-45(2+) overlay assay using a native gel system revealed that the major Ca2+ binding motif of CSQ resides in the asp-rich region (amino acids 354-367). In an in vitro binding assay using a glutathione-S-transferase affinity column, the interaction between CSQ and triadin was found to be Ca2+-dependent, and the site of interaction was confined to the asp-rich region of CSQ. Our results suggest that the asp-rich region of CSQ could participate in the RyR-mediated Ca2+ release process by offering a direct binding site to luminal Ca2+ as well as triadin. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.