Competitive interaction of Seven in absentia homolog-1A and Ca2+/calmodulin with the cytoplasmic tail of group 1 metabotropic glutamate receptors
Competitive interaction of Seven in absentia homolog-1A and Ca2+/calmodulin with the cytoplasmic tail of group 1 metabotropic glutamate receptors
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DOI：
10.1046/j.1365-2443.1999.00269.x
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发表时间：
1999-07-01
期刊：
影响因子：
2.1
通讯作者：
Nakanishi, S
中科院分区：
文献类型：
--
作者：
Ishikawa, K;Nash, SR;Nakanishi, S
背景：1组代谢性谷氨酸受体（mGluR1和mGluR5）通过G蛋白偶联于肌醇三磷酸/Ca2+信号通路，在兴奋性突触传递中发挥重要作用。为了探究1组谷氨酸受体的功能调控，我们利用1组谷氨酸受体胞内羧基末端结构域（1组ct-mGluRs）的酵母双杂交系统，试图鉴定1组谷氨酸受体新的蛋白-蛋白相互作用。结果:双杂交筛选揭示了1组ct-mGluRs与Siah-1A（果蝇7缺失的哺乳动物同源物）之间的特异性相互作用，该相互作用通过泛素/蛋白酶体依赖机制参与光感受器细胞分化，这种相互作用发生在1组ct-mGluRs的同源27-28个氨基酸延伸内，需要后三分之二的Siah-1A。此外，体外结合显示Siah-1A和Ca2+/calmodulin （CaM）结合位点重叠，因此Siah-1A的结合以Ca2+依赖的方式被CaM竞争性地抑制。结论：结果表明1组mGluRs与Siah-1A之间存在直接相互作用，并提示Ca2+/CaM与Siah-1A之间存在竞争性相互作用介导的新型调节机制。
Background: Group 1 metabotropic glutamate receptors (mGluR1 and mGluR5) are coupled to inositol trisphosphate/Ca2+ signaling via G proteins and play an important role in excitatory synaptic transmission, To explore the regulation of group 1 mGluR function, we applied the yeast two-hybrid system using the intracellular carboxy-terminal domain of group 1 mGluRs (group 1 ct-mGluRs) and attempted to identify novel protein-protein interactions of group 1 mGluRs.Results: The two-hybrid screening revealed a specific interaction between group 1 ct-mGluRs and Siah-1A, the mammalian homolog of Drosophila seven in absentia which is involved in photoreceptor cell differentiation via the ubiquitin/proteasome-dependent mechanism, This interaction occurs within a homologous 27-28 amino acid stretch within group 1 ct-mGluRs and requires the latter two-thirds of Siah-1A, Following coexpression in COS-7 cells, myc-tagged Siah-1A was coimmuno-precipitated with the flag-tagged ct-mGluRs by anti-flag antibody, Furthermore, in vitro binding revealed that Siah-1A and Ca2+/calmodulin (CaM) binding sites overlap, such that Siah-1A binding is competitively inhibited by CaM in a Ca2+-dependent manner.Conclusions: The results demonstrate a direct interaction between group 1 mGluRs and Siah-1A and suggest a novel modulatory mechanism mediated by a competitive interaction between Ca2+/CaM and Siah-1A.