Abstract
Osteoblast migration and proliferation are fundamental processes in bone healing. We demonstrated that the G-protein-coupled receptor kinase interacting protein 1(GIT1) is a key regulator of bone mass and osteoblast cell migration, but little is known about GIT1 regulation by upstream signaling systems or the impact of GIT1 on downstream effectors. We found that platelet-derived growth factor (PDGF) stimulated the GIT1 tyrosine phosphorylation in osteoblast cells and increased the association of GIT1 with focal adhesion kinase (FAK) at osteoblast focal adhesions. The Src inhibitor PP2 and FAK siRNA inhibited GIT1 tyrosine phosphorylation and the increased association between GIT1 and FAK following stimulation with PDGF. The spa2 homology domain (SHD) of GIT1 was required for association with FAK. Furthermore, phosphorylation of tyrosine 321 of GIT1, which is localized within the SHD, was critical for association with FAK. Mutagenesis analysis revealed that GIT1Y321F inhibited the increased association between GIT1 and FAK. Immunofluorescent staining revealed that GIT1Y321F inhibited FAK activation in focal adhesions after PGDF stimulation. A cell spreading assay demonstrated that GIT1Y321F also inhibited osteoblast cell motility, while the Boyden chamber assay demonstrated that the GIT1Y321F mutation inhibited PDGF-induced osteoblastic cell migration. Phosphorylation of tyrosine 321 of GIT1 is necessary for PDGF-induced association with FAK, FAK activation in focal adhesions, and for osteoblastic cell migration.
Similar content being viewed by others
References
Tsiridis E, Upadhyay N, Giannoudis P (2007) Molecular aspects of fracture healing: which are the important molecular? Injury 38(suppl 1):S11–S25
Roelofsen T, Akkers R, Beumer W, Apotheker M, Steeghs I, Van de Ven J, Gelderblom C, Garritsen A, Dechering K (2008) Sphingosine-1-phosphate acts as a developmental stage specific inhibitor of PDGF-induced chemotaxis of osteoblasts. J Cell Biochem 105:1128–1138
Gerstenfeld LC, Cullinane DM, Barnes GL et al (2003) Fracture healing as a post-natal developmental process: molecular, spatial, and temporal aspects of its regulation. J Cell Biochem 88:873–884
Mehrotra M, Krane SM, Walters K, Pilbeam C (2004) Differential regulation of platelet-derived growth factor stimulated migration and proliferation in osteoblastic cells. J Cell Biochem 93:741–752
Saldana L, Vilaboa N (2010) Effect of micrometric titanium particles on osteoblast attachment and cytoskeleton architecture. Acta Biomater 6:1649–1660
Bertolucci CM, Guibao CD, Zheng JJ (2008) Phosphorylation of paxillin LD4 destabilizes helix formation and inhibits binding to focal adhesion kinase. Biochemistry 147:548–554
Hoefen R, Berk B (2006) The multifunctional GIT family of proteins. J Cell Sci 119:1469–1475
Yin G, Haendeler J, Yan C, Berk BC (2004) GIT1 functions as a scaffold for MEK1-extracellular signal-regulated kinase 1 and 2 activation by angiotensin II and epidermal growth factor. Mol Cell Biol 24:875–885
Pang J, Hoefen R, Pryhuber G, Wang J, Yin G, White R, Xu X, O’Dell M, Mohan A, Michaloski H, Massett M, Yan C, Berk B (2009) G-protein-coupled receptor kinase interacting protein-1 is required for pulmonary vascular development. Circulation 119:1524–1532
Yin G, Zheng QL, Yan Chen, Bradford CBerk (2005) GIT1 is a scaffold for ERK1/2 activation in focal adhesion. J Biol Chem 280:27705–27712
Menon P, Yin G, Smolock EM, Zuscik MJ, Yan C, Berk BC (2010) GPCR kinase 2 interacting protein 1 (GIT1) regulates osteoclast function and bone mass. J Cell Physiol 225:77–85
Hu Z, Zhang N, Yin G (2007) Src activation required fir pERK1/2 activation in focal adhesions in osteoblasts induced by platelet-derived growth factor. Zhongguo Xiu Fu chong Jian Wai Ke Za Zhi 21:1179–1183
Ilic D, Furuta Y, Kanazawa S, Take N, Sobue K, Nakatsuji N et al (1995) Reduced cell motility and enhanced focal adhesion contact formation in cells from FAK-deficient mice. Nature 377:539–544
Sotobori T, Ueda T, Myoui A, Yoshioka K, Nakasaki M, Yoshikawa H, Itoh K (2006) BMP promotes the hyptotactic migration of murine osteoblastic and osteosarcoma cells by enhancing incorporation of integrin beta 1 into lipid rafts. Exp Cell Res 312:27–38
Van Nieuw Amerongen GP, Natarajan K, Yin G (2004) GIT1 mediates thrombin signaling in endothelial cells: role in turnover of RhoA-type focal adhesion. Cir Res 94:1041–1049
Daher Zeinab, Noel Josette, Claing Audrey (2008) Endothelin-1 promotes migration of endothelial cells through the activation of Arf6 and the regulation of FAK activity. Cell Signal 20:56–65
Schaller MD, Hildebrand JD, Shannon JD, Fox JW, Vines RR, Parsons JT (1994) Autophosphorylation of the focal adhesion kinase, pp 125FAK, directs SH2-dependent binding of pp60src. Mol Cell Biol 14:1680–1688
Schlaepfer DD, Hanks SK, Hunter T, van der Geer P (1994) Integrin-mediated signal transduction linked to Ras pathway by GRB2 binding to focal adhesion kinase. Nature 372:786–791
Brown MC, Cary LA, Jamieson JS, Cooper JA, Turner CE (2005) Src and FAK kinases cooperate to phosphorylate paxillin kinase linker, stimulate its focal adhesion localization, and regulate cell spreading and protrusiveness. Mol Biol Cell 16:4316–4328
Zhang Ning Hu, Zhiyi YinGuoyong (2007) Mechanism of G protein coupled receptor kinase interacting protein 1 RNA hairpin inhibiting osteoblasts migration. Chin J Reparative Reconstr Surg 21:1–5
Tiscornia G, Singer O, Verma IM et al (2006) Production and purification of lentiviral vectors. J Nat Protoc 1:241–245
Walter C, Pabst A, Ziebart T et al (2011) Bisphosphonates affect migration ability and cell viability of HUVEC, fibroblasts and osteoblasts in vitro. Oral Dis 17:194–199
Arkowitz RA, Lowe N (1997) A small conserved domain in the yeast Spa2p is necessary and sufficient for its polarized localization. J Cell Biol 138:17–36
Webb DJ, Mayhew MW, Kovalenko M, Schroeder MJ, Jeffery ED, Whitmore L, Shabanowitz J, Hunt DF, Horwitz AF (2006) Identification of phosphorylation sites in GIT1. J Cell Sci 15:2847–2850
Nakamura M, Nagai A, Tanaka Y, Sekijima Y, Yamashita K (2010) Polarized hydroxyapatite promotes spread and motility of osteoblastic cells. J Biomed Mater Res A 92:783–790
Saura M, Tarin C, Zaragoza C (2010) Recent insights into the implication of nitric oxide in osteoblast differentiation and proliferation during bone development. Sci W J 13:624–632
Kim J-B, Leucht P, Cynthia A et al (2007) Reconciling the role of FAK in osteoblast differentiation, osteoclast remodeling, and bone regeneration. Bone 41:39–51
Smilenov LB, Mikhailov A, Marcantonio EE (1999) Focal adhesion motility revealed in stationary fibroblasts. Science 286:1172–1174
Acknowledgment
This study was supported by National Natural and Science Foundation (81071481), Talent Person in Medicine Foundation (RC2007059) (all foundations to GY).
Author information
Authors and Affiliations
Corresponding author
Additional information
Yongxin Ren and Lipeng Yu contributed equally to this study.
Rights and permissions
About this article
Cite this article
Ren, Y., Yu, L., Fan, J. et al. Phosphorylation of GIT1 tyrosine 321 is required for association with FAK at focal adhesions and for PDGF-activated migration of osteoblasts. Mol Cell Biochem 365, 109–118 (2012). https://doi.org/10.1007/s11010-012-1249-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11010-012-1249-3