The Roles of Osteopontin in Chemotaxis and Haptotaxis Involve the Focal Adhesion Kinase and Integrin-linked Kinase

Abstract: To study the effect of the soluble or anchoring osteopontin (OPN) on focal adhesion kinase (FAK) and integrin-linked kinase (ILK) in vascular smooth muscle cells (VSMCs)， VSMCs were treated with OPN coated on culture flasks or soluble OPN， then the level of FAK and ILK phosphorylation， as well as their interactions were detected. The results showed that OPN coated on culture flasks promoted VSMC adhesion and spreading through haptotaxis. After seeded for 45 min， the number of attached cells on OPN-coated flasks was increased by 1.4 folds compared with control. OPN added in culture media or coated on the culture flasks induced FAK phosphorylation and ILK dephosphorylation， and inhibited FAK interaction with ILK through chemotaxis or haptotaxis. Transfection of the eukaryotic expression vector， pEGFP-C3-β3CD， harboring the cytoplasmic domain of human integrin β3 subunit cDNA inhibited these effects. These results suggest that both soluble and anchoring OPN regulate similarly the integrin downstream molecules FAK and ILK through the cytoplasmic domain of integrin β3 subunit.

CSTR: 32200.14.cjcb.2007.04.0019