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

• 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; calmodulin; calpastatin; CaMKII; Ca^<2+> channel; run-down; CaMK; Ca^<2+> channel

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+>控制多种生理功能，包括基因转录，有节奏的发射，突触传播，激素分泌和激发触发偶联。当通道的胞质侧用人工生理溶液（分摊现象）灌注时，L型Ca^<2+>通道的活性会降低。拆卸的机制仍然未知。我们以前已经报道说，calpastatin（CS）和钙调蛋白（CAM）都可以在破败后恢复Ca^<2+>通道活动。在这项研究中，我们研究了钙调蛋白和钙蛋白酶在Ca^<2+>频道激活中的关系和机制，以及倒下的恢复。主要结果如下。 （1）CAM的分支反向效应取决于通道磷酸化状态。 CAM激酶II将通道保持在可以被CAM重新激活的状态。 （2）CS的域L重新激活L型Ca^<2+>通道。通过筛选域L的短肽，我们发现CS的有效区域位于域L的氨基酸残基45-64中。结果表明，在存在Ca^<2+>的情况下，CS和CAM相互结合。 （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。