Whalen Erin J, Foster Matthew W, Matsumoto Akio, Ozawa Kentaro, Violin Jonathan D, Que Loretta G, Nelson Chris D, Benhar Moran, Keys Janelle R, Rockman Howard A, Koch Walter J, Daaka Yehia, Lefkowitz Robert J, Stamler Jonathan S
Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
Cell. 2007 May 4;129(3):511-22. doi: 10.1016/j.cell.2007.02.046.
beta-adrenergic receptors (beta-ARs), prototypic G-protein-coupled receptors (GPCRs), play a critical role in regulating numerous physiological processes. The GPCR kinases (GRKs) curtail G-protein signaling and target receptors for internalization. Nitric oxide (NO) and/or S-nitrosothiols (SNOs) can prevent the loss of beta-AR signaling in vivo, but the molecular details are unknown. Here we show in mice that SNOs increase beta-AR expression and prevent agonist-stimulated receptor downregulation; and in cells, SNOs decrease GRK2-mediated beta-AR phosphorylation and subsequent recruitment of beta-arrestin to the receptor, resulting in the attenuation of receptor desensitization and internalization. In both cells and tissues, GRK2 is S-nitrosylated by SNOs as well as by NO synthases, and GRK2 S-nitrosylation increases following stimulation of multiple GPCRs with agonists. Cys340 of GRK2 is identified as a principal locus of inhibition by S-nitrosylation. Our studies thus reveal a central molecular mechanism through which GPCR signaling is regulated.
β-肾上腺素能受体（β-ARs）作为典型的G蛋白偶联受体（GPCRs），在调节众多生理过程中发挥着关键作用。GPCR激酶（GRKs）可减少G蛋白信号传导，并将受体靶向内化。一氧化氮（NO）和/或S-亚硝基硫醇（SNOs）能够在体内防止β-AR信号的丧失，但其分子细节尚不清楚。在此，我们在小鼠中发现，SNOs可增加β-AR的表达，并防止激动剂刺激导致的受体下调；在细胞中，SNOs可减少GRK2介导的β-AR磷酸化以及随后β-抑制蛋白向受体的募集，从而导致受体脱敏和内化作用减弱。在细胞和组织中，GRK2均可被SNOs以及一氧化氮合酶进行S-亚硝基化修饰，在用激动剂刺激多个GPCRs后，GRK2的S-亚硝基化水平会升高。GRK2的半胱氨酸340被确定为S-亚硝基化抑制作用的主要位点。因此，我们的研究揭示了一种调节GPCR信号传导的核心分子机制。
