The roles of calpastatin and calmodulin in the regulation of calcium channel

钙蛋白酶抑制剂和钙调蛋白在钙通道调节中的作用

基本信息

批准号：
15570137
负责人：
HAO Li-ying
金额：
$ 1.34万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15570137/
关键词：
calmodulin calpastatin CaMKII Ca^<2+> channel run-down CaMK Ca^<2+> channel

项目摘要

Voltage-gated L-type Ca^<2+> channels control diverse physiological functions including gene transcription, rhythmic firing, synaptic transmission, hormone secretion and excitation-contraction coupling. Activity of L-type Ca^<2+> channel decreases when the cytoplasmic side of the channel is perfused with an artificial physiological solution (run-down phenomenon). The mechanism of run-down is still unknown. We have previously reported that both calpastatin(CS) and calmodulin(CaM) can recover Ca^<2+> channel activity after run-down. In this study, we have investigated the relations and the mechanisms of calmodulin and calpastatin in the activation of Ca^<2+> channel and the reversion of run-down. The main results are as follows. (1)The run-down reversing effect of CaM depends on channel phosphorylation state. CaM kinase II keeps the channel in a state that can be reactivated by CaM. (2)Domain L of CS reactivates the L-type Ca^<2+> channel. By screening the short peptides of domain L, we found that the effective region of CS is located in the amino acid residues 45-64 of domain L. (3)To investigate the relations of CS and CaM, binding between these two molecules were examined with GST-fusion protein pull-down assay. The result shows that CS and CaM bind each other in the presence of Ca^<2+>. (4)Binding sites of CS to Ca^<2+> channel were also investigated. CS might bind to the region that has already confirmed as CaM binding region.

电压门控L-型Ca ^ 2+ 通道控制多种生理功能，包括基因转录、节律性放电、突触传递、激素分泌和兴奋-收缩耦合。当通道的细胞质侧灌注人工生理溶液时，L型Ca 2+ 通道的活性降低(耗尽现象)。衰退的机制仍不清楚。我们之前报道过钙蛋白酶抑制素(CS)和钙调蛋白(CaM)都可以在衰退后恢复Ca^<2+>通道活性。本研究主要研究了钙调蛋白和钙蛋白酶抑制素在Ca^2+通道激活和衰弱逆转中的关系和机制。主要结果如下。 (1)CaM的衰退逆转作用取决于通道磷酸化状态。 CaM 激酶 II 使通道保持在可以被 CaM 重新激活的状态。 (2)CS的L结构域重新激活L型Ca^<2+>通道。通过筛选L结构域的短肽，我们发现CS的有效区域位于L结构域的45-64位氨基酸残基。 (3)为了研究CS和CaM的关系，检测了这两个分子之间的结合。 GST-融合蛋白下拉分析。结果显示CS和CaM在Ca ^ 2+ 存在下彼此结合。 (4)还研究了CS与Ca^2+通道的结合位点。 CS可能与已经确认为CaM结合区域的区域结合。