Calpastatin binds to a calmodulin-binding site of cardiac Cav1.2 Ca2+ channels
Calpastatin binds to a calmodulin-binding site of cardiac Cav1.2 Ca2+ channels
复制标题
Calpastatin 与心脏 Cav1.2 Ca2 通道的钙调蛋白结合位点结合
DOI：
10.1016/j.bbrc.2007.10.017
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发表时间：
2007-12-14
影响因子：
3.1
通讯作者：
Kameyama, Masaki
中科院分区：
文献类型：
--
作者：
Saud, Zahangir A.;Minobe, Etsuko;Kameyama, Masaki
钙蛋白酶抑制素（Calpastatin）是钙蛋白酶的内源性抑制剂，由与Cav1.2通道相互作用的结构域L（CSL）和四个重复的钙蛋白酶抑制结构域组成。我们先前已经发现CSL重新激活心肌细胞的无细胞斑块中Cavl. 2通道的活性[L.Y. Hao，中国粘蝇A.龟山、S. Kuroki，J. Takano，E. Takano，M. Maki，M. Kameyama，Calpastatin domain L is involved in the regulation L-type of Ca2+ channels in guinea pig cardiac myocytes，Biochem. Biophys. Res. Commun. 279（2000）756-761; E. Minobe，L.Y. Hao，Z.A. Saud，J.J. Xu，A.龟山湾Maki，K.K.朱厄尔，T. Parr，R.G. Bardsley，M. Kameyama，A region of calpastatin domain L that reremes cardiac L-type Ca2+ channels，Biochem. Biophys. Res. Commun. 348（2006）288-294]。在这项研究中，我们探索CSL的相互作用网站的Ca 2+通道的下拉方法，使用谷胱甘肽-S-转移酶融合片段肽的Cav1.2通道。CSL直接结合到通道的C末端尾的近端区域，但不与N末端尾、C末端尾的远端区域或重复I-II、II-III或III-IV之间的细胞质环结合。此外，IQ结构域，而不是EF-手样区或CB结构域，在C-末端尾部被发现与CSL结合在一个部分Ca 2+依赖的方式，并在一个可能的竞争方式与钙调素。这些结果表明CSL通过与CavI.2通道C-末端尾部上的钙调蛋白结合位点相互作用来调节Ca 2+通道活性。(C)2007年爱思唯尔公司All rights reserved.
Calpastatin is an endogenous inhibitor of calpain and composed of domain L (CSL), which interacts with the Cavl.2 channels, and four repetitive calpain inhibitory domains. We have previously found that CSL reprimes activity of the Cavl.2 channels in cell-free patches of cardiac myocytes [L.Y. Hao, A. Kameyama, S. Kuroki, J. Takano, E. Takano, M. Maki, M. Kameyama, Calpastatin domain L is involved in the regulation L-type of Ca2+ channels in guinea pig cardiac myocytes, Biochem. Biophys. Res. Commun. 279 (2000) 756-761; E. Minobe, L.Y. Hao, Z.A. Saud, J.J. Xu, A. Kameyama, M. Maki, K.K. Jewell, T. Parr, R.G. Bardsley, M. Kameyama, A region of calpastatin domain L that reprimes cardiac L-type Ca2+ channels, Biochem. Biophys. Res. Commun. 348 (2006) 288-294]. In this study, we explored the CSL interaction site in the Ca2+ channel by the pull-down method, using glutathione-S-transferase-fused fragment peptides of the Cavl.2 channel. CSL bound directly to a proximal region of the C-terminal tail of the channel, but not with the N-terminal tail, a distal region of the C-terminal tail or cytoplasmic loops between repeats I-II, II-III or III-IV. Furthermore IQ domain, but not EF-hand-like region or CB domain, in the C-terminal tail was found to bind with CSL in a partially Ca2+-dependent manner and in a probably competitive manner with calmodulin. These results suggest that CSL modulates Ca2+-channel activity through interacting with the calmodulin-binding site on the C-terminal tail of the CavI.2 channel. (C) 2007 Elsevier Inc. All rights reserved.