GRK2 and arrestin2 regulate UTP-mediated arterial contraction 9. Otero M, Garrad RC, Velazquez B, Hernandez-Perez MG, Camden JM, Erb L et al. Mechanisms of agonist-dependent and -independent desensitization of a recombinant P2Y2 nucleotide receptor. Mol Cell Biochem 2000;205:115 – 123. 10. Willets JM, Challiss RAJ, Nahorski SR. Non-visual GRKs: are we seeing the whole picture? Trends Pharmacol Sci 2003;24:626 – 633. 11. Luttrell LM, Lefkowitz RJ. The role of b-arrestins in the termination and transduction of G-protein-coupled receptor signals. J Cell Sci 2002;115:455 – 465. 12. Hayabuchi Y, Dart C, Standen NB. Evidence for involvement of A-kinase anchoring protein in activation of rat arterial KATP channels by protein kinase-A. J Physiol 2001;536:421 – 427. 13. Nelson CP, Nahorski SR, Challiss RAJ. Temporal proﬁling of changes in phosphatidyl- inositol 4,5-bisphosphate, inositol 1,4,5-trisphosphate and diacylglycerol allows com- prehensive analysis of phospholipase C-initiated signalling in single neurons. J Neurochem 2008;107:602 – 615. 14. Morris GE, Nelson CP, Standen NB, Challiss RAJ, Willets JM. Endothelin signalling in arterial smooth muscle is tightly regulated by G protein-coupled receptor kinase 2. Cardiovasc Res 2010;85:424 – 433. 15. Willets JM, Taylor AH, Shaw H, Konje JC, Challiss RAJ. Selective regulation of H1 his- tamine receptor signaling by G protein-coupled receptor kinase 2 in uterine smooth muscle cells. Mol Endocrinol 2008;22:1893 – 1907. 16. Gitterman DP, Evans RJ. Properties of P2X and P2Y receptors are dependent on artery diameter in the rat mesenteric bed. Br J Pharmacol 2000;131:1561 – 1568. 17. Erlinge D, Hou M, Webb TE, Barnard EA, Moller S. Phenotype changes of the vascular smooth muscle cell regulate P2 receptor expression as measured by quantitative RT-PCR. Biochem Biophys Res Commun 1998;248:864 – 870. 18. Santiago-Perez LI, Flores RV, Santos-Berrios C, Chorna NE, Krugh B, Garrad RC et al. P2Y2 nucleotide receptor signaling in human monocytic cells: activation, desensitiza- tion and coupling to mitogen-activated protein kinases. J Cell Physiol 2001;187: 196 – 208. 19. von Kugelgen I. Pharmacological proﬁles of cloned mammalian P2Y-receptor sub- types. Pharmacol Ther 2006;110:415 – 432. 203 20. Willets JM, Nahorski SR, Challiss RAJ. Roles of phosphorylation-dependent and -independent mechanisms in the regulation of M1 muscarinic acetylcholine recep- tors by G protein-coupled receptor kinase 2 in hippocampal neurons. J Biol Chem 2005;280:18950 – 18958. 21. Harris DM, Cohn HI, Pesant S, Zhou RH, Eckhart AD. Vascular smooth muscle Gq signaling is involved in high blood pressure in both induced renal and genetic vascular smooth muscle-derived models of hypertension. Am J Physiol 2007;293: H3072 – H3079. 22. Cohn HI, Harris DM, Pesant S, Pfeiffer M, Zhou RH, Koch WJ et al. Inhibition of vas- cular smooth muscle G protein-coupled receptor kinase 2 enhances a1D-adrenergic receptor constriction. Am J Physiol 2008;295:H1695 – H1704. 23. Willets JM, Mistry R, Nahorski SR, Challiss RAJ. Speciﬁcity of G protein-coupled receptor kinase 6-mediated phosphorylation and regulation of single-cell m3 muscar- inic acetylcholine receptor signaling. Mol Pharmacol 2003;64:1059 – 1068. 24. Willets JM, Brighton PJ, Mistry R, Morris GE, Konje JC, Challiss RAJ. Regulation of oxy- tocin receptor responsiveness by G protein-coupled receptor kinase 6 in human myometrial smooth muscle. Mol Endocrinol 2009;23:1272 – 1280. 25. Eckhart AD, Ozaki T, Tevaearai H, Rockman HA, Koch WJ. Vascular-targeted over- expression of G protein-coupled receptor kinase-2 in transgenic mice attenuates b-adrenergic receptor signaling and increases resting blood pressure. Mol Pharmacol 2002;61:749 – 758. 26. Hoffmann C, Ziegler N, Reiner S, Krasel C, Lohse MJ. Agonist-selective, receptor- speciﬁc interaction of human P2Y receptors with b-arrestin-1 and -2. J Biol Chem 2008;283:30933 – 30941. 27. Kim J, Zhang L, Peppel K, Wu JH, Zidar DA, Brian L et al. b-Arrestins regulate ather- osclerosis and neointimal hyperplasia by controlling smooth muscle cell proliferation and migration. Circ Res 2008;103:70 – 79. 28. Kim J, Ahn S, Rajagopal K, Lefkowitz RJ. Independent b-arrestin2 and Gq/protein kinase Cz pathways for ERK stimulated by angiotensin type 1A receptors in vascular smooth muscle cells converge on transactivation of the epidermal growth factor receptor. J Biol Chem 2009;284:11953 – 11962.