权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Analysis of Mechanism of Calcium Activation toward to Ras in Neuronal Cell

神经细胞中钙对Ras的激活机制分析

基本信息

批准号：
15500253
负责人：
GOTOH Takaya
金额：
$ 2.3万
依托单位：
Jichi Medical School School of Medicine (2004)The University of Tokyo (2003)
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-15500253/
关键词：
Ras NMDA receptor Neuronal Cell Calcium Channel Knock out Mouse ヌクレオチド交換因子

项目摘要

Previous study showed Ras is key molecule and important player for learning and memory in the brain. However, the signaling pathway of Ras signals is still unclear. We analyzed the calcium and Ras signal pathway that works in the neuron. Last 2 years, we have focused and investigated potential dependent type calcium ion channel using reconstruction ion channel system on the neuronal cell membrane. And we have already reported Ras activator RasGRF1/2 works under calcium signals. Thus, we also analyze RasGRF1/2 function under the reconstruction system. During this study, the research group of the US and France reported the research result which RasGRF1 joins to the NR2B subunit of the Calcium coupled NMDA glutamate receptor (Neuron Vol.40,775-784). Based of these reports, we established the RasGRFs knock-out mouse for studying RasGRF1/2 function in the neuron. We analyzed the tissue slice and primary cell culture from the KO mouse brain and studied protein expression difference of signal molecules. RasGRF1 and RasGRF2 deficient mouse survive respectively. We additionally established RasGRF1/2 double deficient mouse for this study. The double deficient mouse also survived and the neurological development looked normal. Studies on lacking mice revealed that both RasGRF1and RasGRF2 couple NMDA receptors to the activation of the Ras/Erk signaling cascade and to the maintenance of CREB transcription factor activity in cortical neurons of adult mice. Consistent with this function for RasGRFs and the known neuroprotective effect of CREB activity, ischemia-induced CREB activation is reduced in the brains of adult RasGRFs knockout mice and neuronal damage is enhanced. We also found that NMDAs signal through SOS rather than RasGRF in cortical neurons of neonatal. These result imply that Ras-GRFs endow NMDARs with functions unique to mature neurons.

以往的研究表明，Ras是大脑中学习和记忆的关键分子和重要参与者。然而，Ras信号的信号通路仍然不清楚。我们分析了在神经元中起作用的钙和Ras信号通路。近两年来，我们利用神经元细胞膜上的离子通道重建系统，对电位依赖型钙离子通道进行了研究。我们已经报道了Ras激活剂RasGRF 1/2在钙信号下起作用。因此，我们还分析了RasGRF 1/2功能的重建系统。在本研究中，美国和法国的研究小组报道了RasGRF 1与钙偶联NMDA谷氨酸受体的NR 2B亚基连接的研究结果（Neuron Vol.40，775 -784）。在此基础上，我们建立了RasGRFs基因敲除小鼠，用于研究RasGRF 1/2在神经元中的功能。我们分析了KO小鼠脑组织切片和原代细胞培养物，研究了信号分子的蛋白表达差异。RasGRF 1和RasGRF 2缺陷小鼠分别存活。我们还建立了RasGRF 1/2双缺陷小鼠用于本研究。双缺陷小鼠也存活，神经发育看起来正常。对缺失小鼠的研究表明，RasGRF 1和RasGRF 2都将NMDA受体偶联到成年小鼠皮层神经元中Ras/Erk信号级联的激活和CREB转录因子活性的维持。与RasGRF的这种功能和CREB活性的已知神经保护作用一致，在成年RasGRF敲除小鼠的脑中，缺血诱导的CREB活化减少，神经元损伤增强。我们还发现，在新生儿皮层神经元中，NMDA通过SOS而不是RasGRF信号。这些结果意味着Ras-GRF赋予NMDAR成熟神经元特有的功能。