Distinct Agonist Regulation of Muscarinic Acetylcholine M2-M3 Heteromers and Their Corresponding Homomers.
Distinct Agonist Regulation of Muscarinic Acetylcholine M2-M3 Heteromers and Their Corresponding Homomers.
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DOI：
10.1074/jbc.m115.649079
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发表时间：
2015-06-05
期刊：
影响因子：
--
通讯作者：
Milligan G
中科院分区：
文献类型：
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作者：
Aslanoglou D;Alvarez-Curto E;Marsango S;Milligan G
背景：毒蕈碱受体可以形成同源寡聚物和异源寡聚物。结果：M2 和 M3 受体的共表达导致同聚体和异聚体相互作用的同时检测以及激动剂对含 M2 形式的调节。结论：共存的受体寡聚物表现出差异调节。意义：密切相关受体的寡聚物显示出可作为治疗目标的独特特性。 G 蛋白偶联受体的毒蕈碱受体家族的每种亚型均被相似浓度的神经递质乙酰胆碱或密切相关的合成类似物（例如卡巴胆碱）激活。然而，可以通过引入一对突变产生仅由合成配体激活的受体（RASSSL）形式的毒蕈碱受体来产生药理学选择性。这些显示出乙酰胆碱/卡巴胆碱的效力丧失，同时配体氯氮平 N-氧化物的效力增加。野生型人 M2 形式和人 M3 受体 RASSL 变体的共表达导致在稳定转染的 Flp-InTM T-RExTM 293 细胞表面同时检测到 M2-M2 和 M3-M3 同聚体以及 M2-M3 异聚体。在这种情况下，毒蕈碱拮抗剂占据受体对任何毒蕈碱寡聚物都没有可检测到的影响。然而，M2受体的选择性激动剂占据导致M2-M2同聚体相互作用增强，但M2-M3异聚体相互作用减弱。相比之下，M3 RASSSL 受体的选择性激活并没有显着改变 M3-M3 同聚体或 M2-M3 异聚体相互作用。选择性靶向密切相关的受体寡聚体可能提供新的治疗机会。
Background: Muscarinic receptors can form both homo- and hetero-oligomers. Results: Co-expression of M2 and M3 receptors resulted in concurrent detection of both homomer and heteromer interactions and regulation of M2-containing forms by agonist. Conclusion: Co-existing receptor oligomers display differential regulation. Significance: Oligomers of closely related receptors display distinct properties that may be targeted therapeutically. Each subtype of the muscarinic receptor family of G protein-coupled receptors is activated by similar concentrations of the neurotransmitter acetylcholine or closely related synthetic analogs such as carbachol. However, pharmacological selectivity can be generated by the introduction of a pair of mutations to produce Receptor Activated Solely by Synthetic Ligand (RASSL) forms of muscarinic receptors. These display loss of potency for acetylcholine/carbachol alongside a concurrent gain in potency for the ligand clozapine N-oxide. Co-expression of a form of wild type human M2 and a RASSL variant of the human M3 receptor resulted in concurrent detection of each of M2-M2 and M3-M3 homomers alongside M2-M3 heteromers at the surface of stably transfected Flp-InTM T-RExTM 293 cells. In this setting occupancy of the receptors with a muscarinic antagonist was without detectable effect on any of the muscarinic oligomers. However, selective agonist occupancy of the M2 receptor resulted in enhanced M2-M2 homomer interactions but decreased M2-M3 heteromer interactions. By contrast, selective activation of the M3 RASSL receptor did not significantly alter either M3-M3 homomer or M2-M3 heteromer interactions. Selectively targeting closely related receptor oligomers may provide novel therapeutic opportunities.