Allosteric modulation of binding properties between units of chemokine receptor homo- and hetero-oligomers
Allosteric modulation of binding properties between units of chemokine receptor homo- and hetero-oligomers
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DOI：
10.1124/mol.105.019414
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发表时间：
2006-05-01
影响因子：
3.6
通讯作者：
Parmentier, M
中科院分区：
文献类型：
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作者：
Springael, JY;Le Minh, PN;Parmentier, M
我们之前已经证明，趋化因子受体CCR2和CCR5形成同源二聚体和异源二聚体，并且二聚体只能以高亲和力结合单个趋化因子分子。我们在此提供来自生物发光共振能量转移实验的证据，表明趋化因子的刺激不会影响 CCR2/CCR5 异二聚化状态。此外，我们还表明，在“无限”示踪剂稀释条件下，当另一单元的未标记趋化因子配体存在时，放射性配体从异二聚体的一个单元解离的速率急剧增加。这些结果明确证明异二聚体单元之间的相互作用具有变构性质。激动剂以及一些单克隆抗体可以促进这种负结合协同性，表明这种现象不需要与受体激活相关的完全构象变化。最后，我们表明，巨噬细胞炎症蛋白 1 β (CCL4) 与 CCR5 高亲和力结合需要 G 蛋白偶联，并且与 Gpp(NH)p 孵育后，G 蛋白解离会促进预结合放射性标记趋化因子的释放，其动力学与添加过量未标记趋化因子后测得的动力学相似。这些观察结果表明，与 G 蛋白的关联可能参与了受体单体之间观察到的负协同性。我们认为，趋化因子受体和其他 G 蛋白偶联受体的同二聚体和异二聚体之间的负协同作用可能对其体内药理学和与其相关疾病的病理生理学产生重大影响。
We have demonstrated previously that the chemokine receptors CCR2 and CCR5 form homo- and heterodimers and that dimers can only bind a single chemokine molecule with high affinity. We provide here evidence from bioluminescence resonance energy transfer experiments that stimulation by chemokines does not influence the CCR2/CCR5 heterodimerization status. In addition, we show that the rate of radioligand dissociation from one unit of the heterodimer in "infinite" tracer dilution conditions is strongly increased in the presence of an unlabeled chemokine ligand of the other unit. These results demonstrate unambiguously that the interaction between heterodimer units is of allosteric nature. Agonists, but also some monoclonal antibodies, could promote such negative binding cooperativity, indicating that this phenomenon does not require the full conformational change associated with receptor activation. Finally, we show that G protein coupling is required for high-affinity binding of macrophage inflammatory protein-1 beta (CCL4) to CCR5 and that the dissociation from G proteins, after incubation with Gpp(NH)p, promotes the release of prebound radiolabeled chemokines with kinetics similar to those measured after the addition of an excess of unlabeled chemokines. These observations suggest that the association with G proteins probably participates in the negative cooperativity observed between receptor monomers. We propose that negative cooperativity within homo- and heterodimers of chemokine receptors and probably other G protein-coupled receptors will probably have major implications in their pharmacology in vivo and in the physiopathology of the diseases with which they are associated.