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

Pharmacological studies of calmodulin-dependent tau factor phosphorylation in cultured cerebellar granule cells.

培养小脑颗粒细胞中钙调蛋白依赖性 tau 因子磷酸化的药理学研究。

基本信息

批准号：
02671056
负责人：
FUKUNAGA Kohji
金额：
$ 1.28万
依托单位：
Kumamoto Research (C)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Ca^<2+>/calmodulin-dependent protein kinase II(CaM kinase II), which is highly enriched in neural tissues, is a multifunctional protein kinase that is involved in regulation of biosynthesis and release of neurotransmitter, and expression of long-term potentiation(LTP)in CAl region of the hippocampus. Recently, it has been shown in vitro that autophosphorylation of Thr-286/287(alpha/beta subunits)in the CaM kinase II converts it from the Ca^<2+>-dependent form to a partially Ca^<2+>-independent species. We reported evidence for the formation of Ca^<2+>-independent CaM kinase II in cerebellar granule cells following the activation of the glutamate-induced NMDA receptor. In the granule cells, there was a good temporal correlation between autophosphorylation of Thr-287 in CaM kinase II and generation of Ca^<2+>-independent kinase activity. However, as brief exposure(30 sec)of granule cells to glutamate resulted in a relatively transient(<5 min)increase in the Ca^<2+>-independent activity o … More f CaM kinase II. Therefore, we have focused attention on the hippocampal tissue, since involvement of NMDA receptor in the LTP has been clearly shown in the tissue. In cultured hippocampal neurons, glutamate did elevated the Ca^<2+>-independent activity of CaM kinase II as in cerebellar granule cells. The maximal effect on the Ca^<2+>-independence was greater than that in the granule cells and the activity was more stable for at least 30 min in the continued presence of glutamate. In the experiments with _<32>P-labeled cells, the phosphorylation of MAP2 as well as autophosphorylation of CaM kinase II were found to be stimulated by the exposure to glutamate. These results were consistent with the hypothesis that the increase in the postsynaptic Ca^<2+> influx through the NMDA receptor-gated ion channel converts CaM kinase II to a constitutively active, Ca^<2+>-independent form in the hippocampal neurons, and results in an increase in the phosphorylation of target proteins such as MAP2 for the enzyme. Less

钙调素依赖性蛋白激酶II(CaM Kinase II)是一种多功能蛋白激酶，参与调节神经递质的生物合成和释放，参与海马钙区长时程增强(LTP)的表达，在神经组织中高度丰富。最近，体外研究表明，CaM激酶II中Thr-286/287(α/β亚基)的自动磷酸化使其从依赖于钙的形式转变为部分依赖于钙的物种。我们报道了在谷氨酸诱导的NMDA受体激活后，在小脑颗粒细胞中形成钙非依赖性CaM激酶II的证据。在颗粒细胞中，CaM激酶II中Thr-287的自动磷酸化与产生不依赖于Ca~(2+)和Gt；的激酶活性之间存在良好的时间相关性。然而，由于颗粒细胞短暂暴露于谷氨酸(30秒)会导致相对短暂(5分钟)的…钙非依赖性活性增加因此，我们将注意力集中在海马组织上，因为NMDA受体参与LTP在组织中已经被清楚地显示出来。在培养的海马神经元中，谷氨酸确实提高了小脑颗粒细胞中钙非依赖性的CaM激酶II的活性。谷氨酸对钙非依赖性的最大影响大于颗粒细胞，在谷氨酸持续存在的情况下，该活性至少在30min内更稳定。在_&lt；32&gt；P标记细胞的实验中，发现谷氨酸可刺激MAP2的磷酸化和CaM激酶II的自磷酸化。这些结果与以下假设是一致的，即突触后通过NMDA受体门控离子通道的钙离子内流的增加将使海马神经元中的CaM激酶II转变为一种结构性活性的、非钙依赖性的形式，并导致目标蛋白如MAP2对该酶的磷酸化增加。较少