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Functional relationship between Ca^<2+>-dependent cation channel and Ca^<2+>-permeable channel

Ca^<2>依赖性阳离子通道与Ca^<2>渗透通道之间的功能关系

基本信息

批准号：
13670052
负责人：
WAKAMORI Minoru
金额：
$ 2.37万
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：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670052/
关键词：
calcium channel cation TRP Patch-clamp

项目摘要

Ca^<2+> controls diverse cellular processes, which include muscle contraction, neurotransmitter release and other forms of secretion, gene expression, and cell proliferation. To evoke these cellular responses, Ca^<2+> influx across the plasma membrane makes a major contribution to augmenting the cytosolic free Ca^<2+> concentration ([Ca^<2+>]_i). In addition to the well-characterized voltage-gated Ca^<2+> channels and Ca^<2+>-permeable ligand-gated channels, Ca^<2+>-permeable cation channels, activated by downstream of GTP binding protein (G-protein) coupled receptors, have been recognized to be one of the major transmembrane pathways. An important clue to understand the molecular basis of these mammalian Ca^<2+>-permeable cation channels came from the findings of Drosophila visual transduction cascade, since some of the Ca^<2+>-permeable cation channels may be formed by the mammalian homologues of the Drosophila cation channel TRP (the gene product of the transient receptor potential, trp).Currents from HEK cells expressing the TRP3 or the TRP5 were recorded at room temperature using the conventional patch-clamp technique of the whole-cell mode with an Axopatch 200B amplifier. ATP 0.1 mM induced the TRP3 and the TRP5 channel currents at a holding potential of -50 mV in HEK cells expressing the TRP3 and the TRP5, respectively. In the HEK cells expressing the TRP5, extracellular Ca^<2+> at 10 mM induced currents without application of ATP. The current-voltage (I-V) relationships were linear for the TRP3 channel, and outwardly rectified at negative potentials for the TRP5 channel. Ca^<2+> is permeable to TRP5 channel and regulates TRP5 channel.

Ca ^2+控制着多种细胞过程，包括肌肉收缩、神经递质释放和其他形式的分泌、基因表达和细胞增殖。为了引起这些细胞反应，跨质膜的Ca ^2+内流对增加胞质游离Ca ^2+浓度（[Ca ^2 +] i）做出了主要贡献。除了已被充分表征的电压门控Ca ^2+通道和Ca ^2+渗透性配体门控通道外，由GTP结合蛋白（G蛋白）偶联受体下游激活的Ca ^2+渗透性阳离子通道已被认为是主要的跨膜途径之一。理解这些哺乳动物Ca ^2+渗透性阳离子通道的分子基础的一个重要线索来自果蝇视觉转导级联的发现，因为某些Ca ^2+渗透性阳离子通道可能是由果蝇阳离子通道TRP的哺乳动物同系物形成的（瞬时受体电位的基因产物，在室温下使用常规的全细胞膜片钳技术记录来自表达TRP3或TRP5的HEK细胞的电流。使用Axopatch 200B放大器的电池模式。在分别表达TRP3和TRP5的HEK细胞中，0.1 mM ATP在-50 mV的保持电位下诱导TRP3和TRP5通道电流。在表达TRP5的HEK细胞中，在不应用ATP的情况下，10 mM的细胞外Ca ^2+诱导电流。TRP 3通道的电流-电压（I-V）关系呈线性，TRP 5通道在负电位下向外整流。Ca ^<2 +>可渗透TRP 5通道并调节TRP 5通道。