Metabolism and biological activities of lnsP5 and InsP6 in neuronal cells

lnsP5和InsP6在神经元细胞中的代谢和生物活性

基本信息

批准号：
09670104
负责人：
SASAKAWA Nobuyuki
金额：
$ 2.43万
依托单位：
Sophia University (1998)Keio University (1997)
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-09670104/
关键词：
Inositol polyphosphates exocytosis adrenal chromaffin cell シナプトタグミン

项目摘要

Several kinds of stimulants are known to induce inositol1,3,4,5,6-pentakisphosphate (InsP5) and inositol hexakisphosphate (InsP6) accumulations in intact adrenal chromaffin cells, N1E-115 cells and rat cerebellar granule cells. Recently, we suggested that the binding of inositol polyphosphates to the C2B domain of synaptotagmin may clamp spontaneous fusion of the docked or primed vesicles in adrenal chromaffin cells. In this study, we investigated the CaィイD12+ィエD1-evoked release of InsP5 and InsP6, and the effects of the antibodies against synaptotagmin C2A and C2B domains in digitonin-permeabilized adrenal chromaffin cells. When the cells were stimulated with CaィイD12+ィエD1 (100μM), transient increase of InsP5 and InsP6 in the cytosolic medium were observed. Upon a CaィイD12+ィエD1-challenge, amount of InsP5 and InsP6 in the cytosolic medium reached the maximum at 15 sec. Anti-C2A antibody (C2A Ab) completely inhibited CaィイD12+ィエD1-induced InsP5 and InsP6 accumulation in cytosolic medium. Anti-C2B antibody (C2B Ab) also inhibited CaィイD12+ィエD1-induced InsP5 and InsP6 accumulation in the cytosolic medium. Since pretreatment with C2B Ab during permeabilization, but not with C2A Ab, induced increase of InsP5 and InsP6 in the permeabilizing buffer, the mechanisms of the inhibitory effects of the C2B Ab is different from those of C2A Ab. These results strongly suggest that the binding of increased intracellular CaィイD12+ィエD1 to the C2A domain liberate InsP5 and InsP6 from the C2B domain of synaptotagmin, supporting our idea of the clamp of fusion by synaptotagmin and inositol polyphosphates.

已知几种刺激剂在完整的肾上腺染色体细胞，N1E-E-115细胞和大鼠小脑颗粒细胞中，诱导inositol1,3,4,5,6-磷酸盐（INSP5）（INSP5）（INSP5）和肌醇六磷酸磷酸盐（INSP6）。在这项研究中，肌醇整磷酸与C2B域的结合可能会自发融合或FFIN细胞。在胞质培养基中，在胞质培养基中观察到透明度的肾上腺染色体细胞（100μm），在胞质培训中观察到INSP6的透射率，在胞质介质中，INSP6在胞质培养基中观察到INSP6的转移，在15秒内，Y d12+YIE D1诱导的INSP5和INSP6在胞质培养基中的积累也抑制了抗C2B抗体（C2B AB）。在渗透性期间撤退，但在C2A AB期间恢复了渗透性缓冲液中INSP5和INSP6的增加，至C2B AB的抑制作用的机制与C2A AB的抑制作用不同。 D12+IE D1到C2A结构域从突触of的C2B结构域中释放INSP6，支持我们对突触蛋白和肌醇多磷酸盐融合夹的想法。