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Protein kinase C switches the Raf kinase inhibitor from Raf-1 to GRK-2


Feedback inhibition is a fundamental principle in signal transduction allowing rapid adaptation to different stimuli. In mammalian cells, the major feedback inhibitor for G-protein-coupled receptors (GPCR) is G-protein-coupled receptor kinase 2 (GRK-2), which phosphorylates activated receptors, uncouples them from G proteins and initiates their internalization1,2. The functions of GRK-2 are indispensable and need to be tightly controlled3. Dysregulation promotes disorders such as hypertension4 or heart failure5. In our search for a control mechanism for this vital kinase, here we show that the Raf kinase inhibitor protein6,7,8 (RKIP) is a physiological inhibitor of GRK-2. After stimulation of GPCR, RKIP dissociates from its known target, Raf-1 (refs 6–8), to associate with GRK-2 and block its activity. This switch is triggered by protein kinase C (PKC)-dependent phosphorylation of the RKIP on serine 153. The data delineate a new principle in signal transduction: by activating PKC, the incoming receptor signal is enhanced both by removing an inhibitor from Raf-1 and by blocking receptor internalization. A physiological role for this mechanism is shown in cardiomyocytes in which the downregulation of RKIP restrains β-adrenergic signalling and contractile activity.

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Figure 1: RKIP inhibits GRK-2-mediated GPCR phosphorylation.
Figure 2: The RKIP-mediated inhibition of GRK-2 correlates with enhanced signalling and decreased internalization.
Figure 3: PKC switches RKIP from Raf-1 to GRK-2.
Figure 4: Endogenously expressed RKIP enhances receptor-stimulated signalling.


  1. Krupnick, J. G. & Benovic, J. L. The role of receptor kinases and arrestins in G protein-coupled receptor regulation. Annu. Rev. Pharmacol. Toxicol. 38, 289–319 (1998)

    Article  CAS  Google Scholar 

  2. Lefkowitz, R. J., Pitcher, J., Krueger, K. & Daaka, Y. Mechanisms of β-adrenergic receptor desensitization and resensitization. Adv. Pharmacol. 42, 416–420 (1998)

    Article  CAS  Google Scholar 

  3. Jaber, M. et al. Essential role of β-adrenergic receptor kinase 1 in cardiac development and function. Proc. Natl Acad. Sci. USA 93, 12974–12979 (1996)

    Article  ADS  CAS  Google Scholar 

  4. Gros, R., Benovic, J. L., Tan, C. M. & Feldman, R. D. G-protein-coupled receptor kinase activity is increased in hypertension. J. Clin. Invest. 99, 2087–2093 (1997)

    Article  CAS  Google Scholar 

  5. Ungerer, M., Böhm, M., Elce, J. S., Erdmann, E. & Lohse, M. J. Altered expression of β-adrenergic receptor kinase and β2-adrenergic receptors in the failing human heart. Circulation 87, 454–463 (1993)

    Article  CAS  Google Scholar 

  6. Yeung, K. et al. Suppression of Raf-1 kinase activity and MAP kinase signalling by RKIP. Nature 401, 173–177 (1999)

    Article  ADS  CAS  Google Scholar 

  7. Yeung, K. et al. Mechanism of suppression of the Raf/MEK/extracellular signal-regulated kinase pathway by the raf kinase inhibitor protein. Mol. Cell. Biol. 20, 3079–3085 (2000)

    Article  CAS  Google Scholar 

  8. Corbit, K. C. et al. Activation of Raf-1 signaling by protein kinase C through a mechanism involving Raf kinase inhibitory protein. J. Biol. Chem. 278, 13061–13068 (2003)

    Article  CAS  Google Scholar 

  9. Slupsky, J. R. et al. Binding of Gβγ subunits to cRaf1 downregulates G-protein-coupled receptor signalling. Curr. Biol. 9, 971–974 (1999)

    Article  CAS  Google Scholar 

  10. Diviani, D. et al. Effect of different G protein-coupled receptor kinases on phosphorylation and desensitization of the α1B-adrenergic receptor. J. Biol. Chem. 271, 5059–5058 (1996)

    Article  Google Scholar 

  11. Dicker, F., Quitterer, U., Winstel, R., Honold, K. & Lohse, M. J. Phosphorylation-independent inhibition of parathyroid hormone receptor signaling by G protein-coupled receptor kinases. Proc. Natl Acad. Sci. USA 96, 5476–5481 (1999)

    Article  ADS  CAS  Google Scholar 

  12. Lohse, M. J., Benovic, J. L., Caron, M. G. & Lefkowitz, R. J. Multiple pathways of rapid β2-adrenergic receptor desensitization. Delineation with specific inhibitors. J. Biol. Chem. 265, 3202–3211 (1990)

    CAS  PubMed  Google Scholar 

  13. Pitcher, J. A. et al. Role of βγ subunits of G proteins in targeting the β-adrenergic receptor kinase to membrane-bound receptors. Science 257, 1264–1267 (1992)

    Article  ADS  CAS  Google Scholar 

  14. Krasel, C. et al. Phosphorylation of GRK2 by protein kinase C abolishes its inhibition by calmodulin. J. Biol. Chem. 276, 1911–1915 (2001)

    Article  CAS  Google Scholar 

  15. Eichmann, T. et al. The amino-terminal domain of G-protein-coupled receptor kinase 2 is a regulatory Gβγ binding site. J. Biol. Chem. 278, 8052–8057 (2003)

    Article  CAS  Google Scholar 

  16. Yu, Q. M. et al. The amino terminus with a conserved glutamic acid of G protein-coupled receptor kinases is indispensable for their ability to phosphorylate photoactivated rhodopsin. J. Neurochem. 73, 1222–1227 (1999)

    Article  CAS  Google Scholar 

  17. Maudsley, S. et al. The β2-adrenergic receptor mediates extracellular signal-regulated kinase activation via assembly of a multi-receptor complex with the epidermal growth factor receptor. J. Biol. Chem. 275, 9572–9580 (2000)

    Article  CAS  Google Scholar 

  18. Hasuwa, H., Kaseda, K., Einarsdottir, T. & Okabe, M. Small interfering RNA and gene silencing in transgenic mice and rats. FEBS Lett. 532, 227–230 (2002)

    Article  CAS  Google Scholar 

  19. Kallal, L., Gagnon, A. W., Penn, R. B. & Benovic, J. L. Visualization of agonist-induced sequestration and down-regulation of a green fluorescent protein-tagged β2-adrenergic receptor. J. Biol. Chem. 273, 322–328 (1998)

    Article  CAS  Google Scholar 

  20. Mason, C. S. et al. Serine and tyrosine phosphorylations cooperate in Raf-1, but not B-Raf activation. EMBO J. 18, 2137–2148 (1999)

    Article  CAS  Google Scholar 

  21. AbdAlla, S., Lother, H. & Quitterer, U. AT1-receptor heterodimers show enhanced G-protein activation and altered receptor sequestration. Nature 407, 94–98 (2000)

    Article  ADS  CAS  Google Scholar 

  22. AbdAlla, S., Lother, H., el Massiery, A. & Quitterer, U. Increased AT1 receptor heterodimers in preeclampsia mediate enhanced angiotensin II responsiveness. Nature Med. 7, 1003–1009 (2001)

    Article  CAS  Google Scholar 

  23. Darman, R. B. & Forbush, B. A regulatory locus of phosphorylation in the N terminus of the Na-K-Cl cotransporter, NKCCl. J. Biol. Chem. 277, 37542–37550 (2002)

    Article  CAS  Google Scholar 

  24. AbdAlla, S., Lother, H., Abdel-tawab, A. M. & Quitterer, U. The angiotensin II AT2 receptor is an AT1 receptor antagonist. J. Biol. Chem. 276, 39721–39726 (2001)

    Article  CAS  Google Scholar 

  25. Ritter, O. et al. AT2 receptor activation regulates myocardial eNOS expression via the calcineurin-NFAT pathway. FASEB J. 17, 283–285 (2003)

    Article  CAS  Google Scholar 

  26. Wu, J. C., Tsai, R. Y. & Chung, T. H. Role of catenins in the development of gap junctions in rat cardiomyocytes. J. Cell. Biochem. 88, 823–835 (2003)

    Article  CAS  Google Scholar 

  27. Dunigan, C. D., Curran, P. K. & Fishman, P. H. Detection of β-adrenergic receptors by radioligand binding. Methods Mol. Biol. 126, 329–343 (2000)

    CAS  PubMed  Google Scholar 

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We thank W. Kolch for RKIP cDNA plasmids, M. Hoffmann for technical assistance, C. Dees for purification of GRK-2, M. Philipp for help with mouse tissue preparation, H. Mischak for PKCα and PKCδ, N. Burkard and S. Oberdorf-Maass for assistance in preparing cardiomyocytes, and S. Freund for determination of cardiomyocyte beating frequency. This work was supported by the Deutsche Forschungsgemeinschaft.

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Correspondence to Ursula Quitterer.

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Lorenz, K., Lohse, M. & Quitterer, U. Protein kinase C switches the Raf kinase inhibitor from Raf-1 to GRK-2. Nature 426, 574–579 (2003).

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