Abstract
We previously demonstrated that in astrocytes, SDF-1/CXCL12 exclusively signals through CXCR7 despite the additional presence of the alternate SDF-1/CXCL12 receptor, CXCR4. In addition, we provided evidence that astrocytic CXCR7-signalling involves a G protein-dependent mechanism. This is insofar remarkable as in all other cell types studied to date, CXCR7 either acts as a scavenger chemokine receptor, a modulator of CXCR4, or a non-classical chemokine receptor, signalling through ß-arrestin. To begin to unravel the molecular framework impinging the selective function of CXCR7 on a given cell type, we have now analysed the role of G protein-coupled receptor kinases (Grks) in astrocytic CXCR7 signalling. We demonstrate that Grk2 mediates signalling of SDF-1/CXCL12-bound CXCR7 as suggested by the finding that SDF-1/CXCL12-induced activation of Erk1/2 and Akt is abrogated following RNAi-mediated inhibition of Grk2, but not of Grk3, Grk5, or Grk6. We further unravel that Grk2 additionally controls signalling of SDF-1/CXCL12-bound CXCR7 in astrocytes by mediating internalization and subsequent silencing of CXCR7. Finally, we demonstrate that Grk2 is likewise expressed by microglial cells and Schwann cells, cell types in which CXCR7 does not act as a classical chemokine receptor. In conclusion, our findings establish that Grk2 tightly controls CXCR7 signalling in astrocytes, but does not imprint the cell type-specific function of this chemokine receptor.
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References
Balabanian K, Lagane B, Infantino S, Chow KY, Harriague J, Moepps B, Arenzana-Seisdedos F, Thelen M, Bachelerie F (2005) The chemokine SDF-1/CXCL12 binds to and signals through the orphan receptor RDC1 in T lymphocytes. J Biol Chem 280:35760–35766
Balabanian K, Levoye A, Klemm L, Lagane B, Hermine O, Harriague J, Baleux F, Arenzana-Seisdedos F, Bachelerie F (2008) Leukocyte analysis from WHIM syndrome patients reveals a pivotal role for GRK3 in CXCR4 signaling. J Clin Invest 118:1074–1084
Boldajipour B, Mahabaleshwar H, Kardash E, Reichman-Fried M, Blaser H, Minina S, Wilson D, Xu Q, Raz E (2008) Control of chemokine-guided cell migration by ligand sequestration. Cell 132:463–473
Brockes JP, Fields KL, Raff MC (1979) Studies on cultured rat Schwann cells. I. Establishment of purified populations from cultures of peripheral nerve. Brain Res 165:105–118
Burns JM, Summers BC, Wang Y, Melikian A, Berahovich R, Miao Z, Penfold ME, Sunshine MJ, Littman DR, Kuo CJ, Wei K, McMaster BE, Wright K, Howard MC, Schall TJ (2006) A novel chemokine receptor for SDF-1 and I-TAC involved in cell survival, cell adhesion, and tumor development. J Exp Med 203:2201–2213
Busillo JM, Armando S, Sengupta R, Meucci O, Bouvier M, Benovic JL (2010) Site-specific phosphorylation of CXCR4 is dynamically regulated by multiple kinases and results in differential modulation of CXCR4 signaling. J Biol Chem 285:7805–7817
Décaillot FM, Kazmi MA, Lin Y, Ray-Saha S, Sakmar TP, Sachdev P (2011) CXCR7/CXCR4 heterodimer constitutively recruits beta-arrestin to enhance cell migration. J Biol Chem 286:32188–32197
Dorf ME, Berman MA, Tanabe S, Heesen M, Luo Y (2000) Astrocytes express functional chemokine receptors. J Neuroimmunol 111:109–121
Evron T, Daigle TL, Caron MG (2012) GRK2: multiple roles beyond G protein-coupled receptor desensitization. Trends Pharmacol Sci 33:154–164
Ferguson SS (2007) Phosphorylation-independent attenuation of GPCR signalling. Trends Pharmacol Sci 28:173–179
Figiel M, Maucher T, Rozyczka J, Bayatti N, Engele J (2003) Regulation of glial glutamate transporter expression by growth factors. Exp Neurol 183:124–135
Fong AM, Premont RT, Richardson RM, Yu YR, Lefkowitz RJ, Patel DD (2002) Defective lymphocyte chemotaxis in beta-arrestin2- and GRK6-deficient mice. Proc Natl Acad Sci USA 99:7478–7483
Furusato B, Mohamed A, Uhlén M, Rhim JS (2010) CXCR4 and cancer. Pathol Int 60:497–505
Giulian D, Baker TJ (1986) Characterization of ameboid microglia isolated from developing mammalian brain. J Neurosci 6:2163–2178
Hattermann K, Held-Feindt J, Lucius R, Müerköster SS, Penfold ME, Schall TJ, Mentlein R (2010) The chemokine receptor CXCR7 is highly expressed in human glioma cells and mediates antiapoptotic effects. Cancer Res 70:3299–3308
Jones KL, Maguire JJ, Davenport AP (2011) Chemokine receptor CCR5: from AIDS to atherosclerosis. Br J Pharmacol 162:1453–1469
Kalatskaya I, Berchiche YA, Gravel S, Limberg BJ, Rosenbaum JS, Heveker N (2009) AMD3100 is a CXCR7 ligand with allosteric agonist properties. Mol Pharmacol 75:1240–1247
Kim JI, Chakraborty P, Wang Z, Daaka Y (2012) G-protein coupled receptor kinase 5 regulates prostate tumor growth. J Urol 187:322–329
Levoye A, Balabanian K, Baleux F, Bachelerie F, Lagane B (2009) CXCR7 heterodimerizes with CXCR4 and regulates CXCL12-mediated G protein signaling. Blood 113:6085–6093
Li M, Ransohoff RM (2008) Multiple roles of chemokine CXCL12 in the central nervous system: a migration from immunology to neurobiology. Prog Neurobiol 84:116–131
Luker KE, Gupta M, Steele JM, Foerster BR, Luker GD (2009) Imaging ligand-dependent activation of CXCR7. Neoplasia 11:1022–1035
Luo Y, Berman MA, Zhai Q, Fischer FR, Abromson-Leeman SR, Zhang Y, Kuziel WA, Gerard C, Dorf ME (2002) RANTES stimulates inflammatory cascades and receptor modulation in murine astrocytes. Glia 39:19–30
Ma Q, Jones D, Borghesani PR, Segal RA, Nagasawa T, Kishimoto T, Bronson RT, Springer TA (1998) Impaired B-lymphopoiesis, myelopoiesis, and derailed cerebellar neuron migration in CXCR4- and SDF-1-deficient mice. Proc Natl Acad Sci USA 95:9448–9453
Maksym RB, Tarnowski M, Grymula K, Tarnowska J, Wysoczynski M, Liu R, Czerny B, Ratajczak J, Kucia M, Ratajczak MZ (2009) The role of stromal-derived factor-1–CXCR7 axis in development and cancer. Eur J Pharmacol 625:31–40
Moser E, Kargl J, Whistler JL, Waldhoer M, Tschische P (2010) G protein-coupled receptor-associated sorting protein 1 regulates the postendocytic sorting of seven-transmembrane-spanning G protein-coupled receptors. Pharmacology 86:22–29
Naumann U, Cameroni E, Pruenster M, Mahabaleshwar H, Raz E, Zerwes HG, Rot A, Thelen M (2010) CXCR7 functions as a scavenger for CXCL12 and CXCL11. PLoS ONE 5:e9175
Ödemis V, Lamp E, Pezeshki G, Moepps B, Schilling K, Gierschik P, Littman DR, Engele J (2005) Mice deficient in the chemokine receptor CXCR4 exhibit impaired limb innervation and myogenesis. Mol Cell Neurosci 30:494–505
Ödemis V, Boosmann K, Heinen A, Küry P, Engele J (2010) CXCR7 is an active component of SDF-1 signalling in astrocytes and Schwann cells. J Cell Sci 123:1081–1088
Ödemis V, Lipfert J, Kraft R, Hajek P, Abraham G, Hattermann K, Mentlein R, Engele J (2012) The presumed atypical chemokine receptor CXCR7 signals through G(i/o) proteins in primary rodent astrocytes and human glioma cells. Glia 60:372–381
Penela P, Murga C, Ribas C, Lafarga V, Mayor F Jr (2010) The complex G protein-coupled receptor kinase 2 (GRK2) interactome unveils new physiopathological targets. Br J Pharmacol 160:821–832
Premont RT, Gainetdinov RR (2007) Physiological roles of G protein-coupled receptor kinases and arrestins. Annu Rev Physiol 69:511–534
Rajagopal S, Kim J, Ahn S, Craig S, Lam CM, Gerard NP, Gerard C, Lefkowitz RJ (2010) Beta-arrestin- but not G protein-mediated signaling by the “decoy” receptor CXCR7. Proc Natl Acad Sci USA 107:628–632
Ray P, Mihalko LA, Coggins NL, Moudgil P, Ehrlich A, Luker KE, Luker GD (2012) Carboxy-terminus of CXCR7 regulates receptor localization and function. Int J Biochem Cell Biol 44:669–678
Reiter E, Lefkowitz RJ (2006) GRKs and beta-arrestins: roles in receptor silencing, trafficking and signaling. Trends Endocrinol Metab 17:159–165
Ribas C, Penela P, Murga C, Salcedo A, García-Hoz C, Jurado-Pueyo M, Aymerich I, Mayor F Jr (2007) The G protein-coupled receptor kinase (GRK) interactome: role of GRKs in GPCR regulation and signaling. Biochim Biophys Acta 1768:913–922
Sierro F, Biben C, Martínez-Muñoz L, Mellado M, Ransohoff RM, Li M, Woehl B, Leung H, Groom J, Batten M, Harvey RP, Martínez-A C, Mackay CR, Mackay F (2007) Disrupted cardiac development but normal hematopoiesis in mice deficient in the second CXCL12/SDF-1 receptor, CXCR7. Proc Natl Acad Sci USA 104:14759–14764
Sun X, Cheng G, Hao M, Zheng J, Zhou X, Zhang J, Taichman RS, Pienta KJ, Wang J (2010) CXCL12/CXCR4/CXCR7 chemokine axis and cancer progression. Cancer Metastasis Rev 29:709–722
Tachibana K, Hirota S, Iizasa H, Yoshida H, Kawabata K, Kataoka Y, Kitamura Y, Matsushima K, Yoshida N, Nishikawa S, Kishimoto T, Nagasawa T (1998) The chemokine receptor CXCR4 is essential for vascularization of the gastrointestinal tract. Nature 393:591–594
Thelen M, Thelen S (2008) CXCR7, CXCR4 and CXCL12: an eccentric trio? J Neuroimmunol 198:9–13
Vroon A, Heijnen CJ, Raatgever R, Touw IP, Ploemacher RE, Premont RT, Kavelaars A (2004) GRK6 deficiency is associated with enhanced CXCR4-mediated neutrophil chemotaxis in vitro and impaired responsiveness to G-CSF in vivo. J Leukoc Biol 75:698–704
Zabel BA, Wang Y, Lewén S, Berahovich RD, Penfold ME, Zhang P, Powers J, Summers BC, Miao Z, Zhao B, Jalili A, Janowska-Wieczorek A, Jaen JC, Schall TJ (2009) Elucidation of CXCR7-mediated signaling events and inhibition of CXCR4-mediated tumor cell transendothelial migration by CXCR7 ligands. J Immunol 183:3204–3211
Zou YR, Kottmann AH, Kuroda M, Taniuchi I, Littman DR (1998) Function of the chemokine receptor CXCR4 in haematopoiesis and in cerebellar development. Nature 393:595–599
Acknowledgments
We thank Patrick Küry for providing us with primary Schwann cells. This work was supported by the Deutsche Forschungsgemeinschaft (En 187/5-9).
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Authors Jana Lipfert and Veysel Ödemis contributed equally.
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Lipfert, J., Ödemis, V. & Engele, J. Grk2 is an Essential Regulator of CXCR7 Signalling in Astrocytes. Cell Mol Neurobiol 33, 111–118 (2013). https://doi.org/10.1007/s10571-012-9876-5
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DOI: https://doi.org/10.1007/s10571-012-9876-5