Working mechanism of Ca^<2+>/calmodulin-dependent protein kinase II in synaptic plasticity

Ca^2/钙调蛋白依赖性蛋白激酶II在突触可塑性中的作用机制

• 批准号: 09670096
• 负责人: FUKUNAGA Kohji
• 金额: $ 2.3万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09670096/
• 关键词: CaM kinase II; autophosphorylation; hippocampus; synaptic plasticity; long-term potentiation; NMDA receptor; CA1; protein phosphatase 2A; 長期増強; スパイン; CAI領域; グルタミン酸受容体; カルシニューリン; カルモデュリン

The observation that autophosphorylation of threonine at position 286 (Thr-286) in Ca^<2+>/calmodulin-dependent protein kinase II (CaM kinase II) converts it from the Ca^<2+>-dependent form to the Ca^<2+>-independent form (constitutively active form) have led to hypothesis that the formation of Ca^<2+>-independent form of the enzyme could encode the frequency of synaptic usage and serve as a molecular switch of "memory". Indeed, induction of long-term potentiation (LTP) in CA1 region of hippocampal slices was associated with long-lasting increases in Ca^<2+>-independent and total activities of CaM kinase IL as well as an increase in the autophosphorylation. We further confirmed with a specific antibody recognized the autophosphorylation of Thr-286 that high, but not low frequency stimulation applied to CA1 afferents resulted in increases in immunofluorescent intensity in the cell bodies and dendrites in the CA1 neurons after LTP induction. The strong immunoreactivities with the anti-ph … More ospho-specific antibody were co-localized with immunoreactivities against NMDA receptor in the CA1 regions. Since the Ca^<2+>-independent activity can be reversed by protein phosphatases, we next investigated regulation of protein phosphatase activity during LTP induction. A significant decrease in protein phosphatase 2A activity in the soluble fractions was observed in the CA1 regions following LTP induction without change in protein phosphatase 2C activity using autophosphorylated CaM kinase II as substrate. In vitro and in vivo studies revealed that phosphorylation of B'alpha subunit, a regulatory subunit of protein phosphatase 2A, by CaM kinase II is underlying the inhibition of the protein phosphatase activity during LTP induction. These results suggest that the decreased protein phosphatase 2A activity by CaM kiriase II can synergistically contribute to the expression of LTP by favoring generation of the constitutively active CaM kinase II and by regulating the phosphorylation of specific synaptic proteins. Less

Ca^2+/钙调素依赖性蛋白激酶II中286位苏氨酸（Thr-286）自身磷酸化的观察CaM激酶II将其从依赖Ca^2+的形式转化为不依赖Ca^2+的形式（组成型活性形式）导致了一种假设，即Ca^<2+>-这种酶的独立形式可以编码突触使用的频率，并作为“记忆”的分子开关。事实上，海马脑片CA 1区长时程增强（LTP）的诱导与钙调素激酶IL的非Ca^<2+>依赖性活性和总活性的长期增加以及自身磷酸化的增加有关。我们进一步证实了一个特定的抗体识别的Thr-286的自磷酸化，高，但不是低频率的刺激施加到CA 1传入导致在LTP诱导后，在CA 1神经元的细胞体和树突的免疫荧光强度增加。抗ph抗体的强免疫反应性 ...更多信息 Opho特异性抗体与NMDA受体的免疫反应共定位于CA 1区。由于不依赖Ca^<2+>的活性可以被蛋白磷酸酶逆转，我们接下来研究了LTP诱导过程中蛋白磷酸酶活性的调节。使用自磷酸化CaM激酶II作为底物，LTP诱导后，在CA 1区观察到可溶性组分中蛋白磷酸酶2A活性显着降低，而蛋白磷酸酶2C活性没有变化。体外和体内研究表明，在LTP诱导过程中，CaM激酶II对蛋白磷酸酶2A的调节亚基B 'α亚基的磷酸化是抑制蛋白磷酸酶活性的基础。这些结果表明，降低蛋白磷酸酶2A活性的CaM kiriase II可以协同有助于LTP的表达，有利于生成的组成型活性的CaM激酶II，并通过调节特定的突触蛋白的磷酸化。少

项目成果

M.Ohmitsu, K.Fukunaga, H.Yamamoto and E.Miyamoto: "Phosphorylation of myristolated alanine-rich protein kinase C substrate by mitogen-activated protein kinase in cultured rat hippocampal neurons following stimulation of glutamate receotors." J.Biol.Chem.2

M.Ohmitsu、K.Fukunaga、H.Yamamoto 和 E.Miyamoto：“在刺激谷氨酸受体后，培养的大鼠海马神经元中丝裂原激活的蛋白激酶对肉豆蔻酸富含丙氨酸的蛋白激酶 C 底物进行磷酸化。”

K.Fukunaga and E.Miyamoto: "Neuronal plasticity and protein phosphatase. (in Japanese) (Special Issue "Structure and function of protein phosphatase")." Tanpakushitsu Kakusan Kohso. 43. 1062-1071 (1998)

K.Fukunaga 和 E.Miyamoto：“神经元可塑性和蛋白磷酸酶。（日语）（特刊“蛋白磷酸酶的结构和功能”）。

Motohiro Morioka: "Serine/threonine phosphatase activity of calcineurin is inhibited by sodium orthovanadate and dithiothreitol reverses the inhibitory effect." Biochem. Biophys. Res. Commun.253. 342-345 (1998)

Motohiro Morioka：“钙调神经磷酸酶的丝氨酸/苏氨酸磷酸酶活性被原钒酸钠抑制，而二硫苏糖醇则逆转了抑制作用。”

H.Kimura, K.Fukunaga, Y.Ushio and E.Miyamoto: "Basic fibroblast growth factor stimulates phosphorylation of CCAAT/enhancer-binding protein d by activation of mitogen-activated protein kinase." Biomedical Res.19. 65-75 (1998)

H.Kimura、K.Fukunaga、Y.Ushio 和 E.Miyamoto：“碱性成纤维细胞生长因子通过激活丝裂原激活蛋白激酶来刺激 CCAAT/增强子结合蛋白 d 的磷酸化。”

Kohji Fukunaga: "current studies on a working model of CaM kinase II in hippocampal long-term potentiation and memory." Jpn.J.Pharmacol.79. 7-15 (1999)

Kohji Fukunaga：“目前关于 CaM 激酶 II 在海马长时程增强和记忆中的工作模型的研究。”