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与内源性儿茶酚胺相比,异丙肾上腺素在刺激β肾上腺素能受体(βAR)与β抑制蛋白2(β-arrestin2)相互作用方面表现出独特的激酶依赖性。

Isoprenaline shows unique kinase dependencies in stimulating βAR-β-arrestin2 interaction compared to endogenous catecholamines.

作者信息

Matthees Edda S F, Kletzin Luca E, Löbbert Arnelle, Hoffmann Jana S, Große Carolin, Gossert Alvar D, Hoffmann Carsten

机构信息

Institute for Molecular Cell Biology, Center for Molecular Biomedicine, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Hans-Knöll-Straße 2, Jena, Germany.

Institute for Molecular Cell Biology, Center for Molecular Biomedicine, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, Hans-Knöll-Straße 2, Jena, Germany.

出版信息

Mol Pharmacol. 2025 Jun;107(6):100041. doi: 10.1016/j.molpha.2025.100041. Epub 2025 Apr 21.

Abstract

The β1-adrenergic receptor (βAR) is an essential G protein-coupled receptor in the heart. Its dysregulation represents a hallmark of cardiac diseases. Studies have identified a unique mode of β-arrestin interaction, where βAR briefly engages with β-arrestins before catalytically accumulating them at the plasma membrane (PM) independently of the receptor. Although receptor phosphorylation crucially impacts β-arrestins, the contributions of specific kinases vital in βAR regulation remain unclear. Here, we employed G protein-coupled receptor kinase (GRK) GRK2/3/5/6 knockout cells and the protein kinase A inhibitor H89 in bioluminescence resonance energy transfer-based assays to systematically assess GRKs and protein kinase A in direct β-arrestin2 recruitment to βAR and β-arrestin2 translocation to the PM. Furthermore, we compared the effects of the synthetic agonist isoprenaline with the endogenous catecholamines: epinephrine and norepinephrine. We observed pronounced differences in their kinase dependencies to mediate β-arrestin2 translocation to the PM. Upon isoprenaline stimulation, GRKs strongly influenced β-arrestin2 translocation to the PM but had no effect on direct β-arrestin2 recruitment to βAR. Additionally, in a GRK2-specific context, protein kinase A inhibition primarily reduced the efficacy of isoprenaline for β-arrestin2 translocation, whereas for GRK5, it decreased potency. Strikingly, these kinase-dependent effects were absent for epinephrine and norepinephrine, suggesting distinct underlying molecular mechanisms for β-arrestin2 accumulation at the PM. This observation could be explained by agonist-specific differences in receptor conformational rearrangements, as suggested by distinct changes in the NMR spectra of βAR. Our findings highlight that synthetic and endogenous ligands induce distinct molecular mechanisms in βAR regulation, emphasizing the need to consider these differences when translating molecular insights into physiological contexts. SIGNIFICANCE STATEMENT: Our findings reveal mechanistic differences in β1-adrenergic receptor-mediated catalytic activation of β-arrestin2 by synthetic and endogenous agonists, driven by distinct G protein-coupled receptor kinases and protein kinase A dependencies. Although β-arrestin2 translocation to the PM occurred to similar extents with isoprenaline, epinephrine, and norepinephrine, kinase involvement was crucial only upon Iso stimulation of β1-adrenergic receptor. By elucidating these ligand-specific pathways, this study advances our understanding of β1-adrenergic receptor signaling and regulation while additionally highlighting the importance of considering these differences when translating molecular insights into pathophysiological contexts.

摘要

β1-肾上腺素能受体(βAR)是心脏中一种重要的G蛋白偶联受体。其调节异常是心脏疾病的一个标志。研究已经确定了一种独特的β-抑制蛋白相互作用模式,即βAR在将β-抑制蛋白催化性地积累于质膜(PM)之前,会先短暂地与它们结合,且这一过程独立于受体。尽管受体磷酸化对β-抑制蛋白起着关键作用,但在βAR调节中至关重要的特定激酶的作用仍不清楚。在这里,我们在基于生物发光共振能量转移的实验中使用了G蛋白偶联受体激酶(GRK)GRK2/3/5/6基因敲除细胞和蛋白激酶A抑制剂H89,以系统评估GRK和蛋白激酶A在直接将β-抑制蛋白2募集到βAR以及β-抑制蛋白2转位到质膜过程中的作用。此外,我们比较了合成激动剂异丙肾上腺素与内源性儿茶酚胺(肾上腺素和去甲肾上腺素)的作用效果。我们观察到它们在介导β-抑制蛋白2转位到质膜的激酶依赖性上存在显著差异。在异丙肾上腺素刺激下,GRK强烈影响β-抑制蛋白2转位到质膜,但对直接将β-抑制蛋白2募集到βAR没有影响。此外,在GRK2特异性的情况下,抑制蛋白激酶A主要降低了异丙肾上腺素促进β-抑制蛋白2转位的效力,而对于GRK5,它降低了效能。令人惊讶的是,肾上腺素和去甲肾上腺素不存在这些激酶依赖性效应,这表明在质膜上β-抑制蛋白2积累的潜在分子机制不同。正如βAR的核磁共振光谱的明显变化所表明的,这一观察结果可以通过受体构象重排中激动剂特异性差异来解释。我们的研究结果强调,合成配体和内源性配体在βAR调节中诱导不同的分子机制,这突出了在将分子见解转化为生理背景时考虑这些差异的必要性。重要性声明:我们的研究结果揭示了合成激动剂和内源性激动剂在β1-肾上腺素能受体介导的β-抑制蛋白2催化激活过程中的机制差异,这是由不同的G蛋白偶联受体激酶和蛋白激酶A依赖性驱动的。尽管异丙肾上腺素、肾上腺素和去甲肾上腺素使β-抑制蛋白2转位到质膜的程度相似,但激酶的参与仅在β1-肾上腺素能受体受到异丙肾上腺素刺激时才至关重要。通过阐明这些配体特异性途径,本研究推进了我们对β1-肾上腺素能受体信号传导和调节的理解,同时还强调了在将分子见解转化为病理生理背景时考虑这些差异的重要性。

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