人源趋化因子受体 CXCR4 的早期信号转导的动力学分析。
Kinetic Analysis of the Early Signaling Steps of the Human Chemokine Receptor CXCR4.
机构信息
Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.).
Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), University Hospital Jena, University of Jena, Jena, Germany (C.P.-V., C.H.); Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany (C.P.-V., A.I., M.J.L., C.H.); Max-Delbrück Center for Molecular Medicine, Berlin, Germany (A.I., M.J.L.); Amsterdam Institute for Molecules Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Vrije Universiteit, Amsterdam, The Netherlands (A.Z., M.J.S.); Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Medical School, Queen's Medical Centre, Nottingham, United Kingdom (B.C., L.E.K., S.J.H.); and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands, United Kingdom (B.C., L.E.K., S.J.H.)
出版信息
Mol Pharmacol. 2020 Aug;98(2):72-87. doi: 10.1124/mol.119.118448. Epub 2020 May 30.
G protein-coupled receptors (GPCRs) are biologic switches that transduce extracellular stimuli into intracellular responses in the cell. Temporally resolving GPCR transduction pathways is key to understanding how cell signaling occurs. Here, we investigate the kinetics and dynamics of the activation and early signaling steps of the CXC chemokine receptor (CXCR) 4 in response to its natural ligands CXC chemokine ligand (CXCL) 12 and macrophage migration inhibitory factor (MIF), using Förster resonance energy transfer-based approaches. We show that CXCR4 presents a multifaceted response to CXCL12, with receptor activation (≈0.6 seconds) followed by a rearrangement in the receptor/G protein complex (≈1 seconds), a slower dimer rearrangement (≈1.7 seconds), and prolonged G protein activation (≈4 seconds). In comparison, MIF distinctly modulates every step of the transduction pathway, indicating distinct activation mechanisms and reflecting the different pharmacological properties of these two ligands. Our study also indicates that CXCR4 exhibits some degree of ligand-independent activity, a relevant feature for drug development. SIGNIFICANCE STATEMENT: The CXC chemokine ligand (CXCL) 12/CXC chemokine receptor (CXCR) 4 axis represents a well-established therapeutic target for cancer treatment. We demonstrate that CXCR4 exhibits a multifaceted response that involves dynamic receptor dimer rearrangements and that is kinetically embedded between receptor-G protein complex rearrangements and G protein activation. The alternative endogenous ligand macrophage migration inhibitory factor behaves opposite to CXCL12 in each assay studied and does not lead to G protein activation. This detailed understanding of the receptor activation may aid in the development of more specific drugs against this target.
G 蛋白偶联受体（GPCRs）是一种生物开关，可将细胞外刺激转换为细胞内反应。解析 GPCR 转导途径的时间是理解细胞信号转导如何发生的关键。在这里，我们使用基于Förster 共振能量转移的方法研究了 CXC 趋化因子受体（CXCR）4 对其天然配体 CXC 趋化因子配体（CXCL）12 和巨噬细胞移动抑制因子（MIF）的激活和早期信号转导步骤的动力学和动态。我们表明，CXCR4 对 CXCL12 表现出多方面的反应，受体激活（≈0.6 秒）后，受体/G 蛋白复合物发生重排（≈1 秒），较慢的二聚体重排（≈1.7 秒），以及延长的 G 蛋白激活（≈4 秒）。相比之下，MIF 明显调节信号转导途径的每个步骤，表明存在不同的激活机制，并反映了这两种配体的不同药理学特性。我们的研究还表明，CXCR4 表现出一定程度的配体非依赖性活性，这是药物开发的一个相关特征。
意义
CXC 趋化因子配体（CXCL）12/CXC 趋化因子受体（CXCR）4 轴是癌症治疗的一个成熟的治疗靶点。我们证明，CXCR4 表现出一种多方面的反应，涉及动态受体二聚体重排，并且在受体-G 蛋白复合物重排和 G 蛋白激活之间在动力学上嵌入。在研究的每种测定中，替代的内源性配体巨噬细胞移动抑制因子的行为与 CXCL12 相反，并且不会导致 G 蛋白激活。对受体激活的这种详细了解可能有助于开发针对该靶标的更特异性药物。
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