The extreme C-terminus of GluRδ2 is essential for induction of long-term depression in cerebellar slices
The extreme C-terminus of GluRδ2 is essential for induction of long-term depression in cerebellar slices
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DOI：
10.1111/j.1460-9568.2007.05412.x
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发表时间：
2007-03-01
影响因子：
3.4
通讯作者：
Yuzaki, Michisuke
中科院分区：
文献类型：
--
作者：
Kohda, Kazuhisa;Kakegawa, Wataru;Yuzaki, Michisuke
小脑中平行纤维（PF）-浦肯野细胞突触的长期抑制（LTD）被认为是运动学习的细胞基础。尽管 delta 2 谷氨酸受体 (GluR delta 2) 已被证明对于 LTD 至关重要，但 GluR delta 2 发挥作用的机制仍然难以捉摸。在这项研究中，我们开发了一种基于病毒载体的基因转移方法，以挽救小脑切片制剂中 GluR δ 2 缺失浦肯野细胞中受损的 LTD。我们证明，在用野生型转导的 GluR delta 2 缺失浦肯野细胞中，LTD 得到恢复，而用突变型 GluR delta 2 则不能恢复，突变型 GluR delta 2 在 C 末端缺乏 PDZ 配体结构域。免疫组织化学分析显示，病毒引入的野生型和突变型 GluR delta 2 蛋白之间的表达水平或脊柱定位模式没有差异。同样，在用肽急剧灌注的浦肯野细胞中，LTD 被消除，阻碍了 GluR delta 2 与 PDZ 蛋白（如 PSD-93、PTPMEG 和 S-SCAM）的相互作用，但不与飞燕草蛋白相互作用。总之，这些结果表明，与 GluR delta 2 C 末端结合的 PDZ 蛋白对于在突触处定位 GluR delta 2 并不是必需的，但对于传递诱导 LTD 所需的信号至关重要。
Long-term depression (LTD) of parallel fibre (PF)-Purkinje cell synapses in the cerebellum is recognized as a cellular substrate of motor learning. Although the delta 2 glutamate receptor (GluR delta 2) has been shown to be crucial for LTD, the mechanisms by which GluR delta 2 functions remain elusive. In this study, we developed a virus vector-based gene transfer approach to rescue impaired LTD in GluR delta 2-null Purkinje cells in cerebellar slice preparations. We demonstrated that LTD was restored in GluR delta 2-null Purkinje cells transduced with wild-type but not with mutant GluR delta 2, which lacked the PDZ-ligand domain in the C-terminus. Immunohistochemical analysis revealed no difference in expression levels or spine localization patterns between virally introduced wild-type and mutant GluR delta 2 proteins. Similarly, LTD was abrogated in Purkinje cells that had been acutely perfused with peptides, hampering the interaction of GluR delta 2 with PDZ proteins such as PSD-93, PTPMEG and S-SCAM but not with delphilin. Together, these results indicate that PDZ proteins that bind to the C-terminus of GluR delta 2 are not essential for localizing GluR delta 2 at synapses but are crucial for conveying signals necessary for the induction of LTD.