Abstract: Objective: To investigate the effects of DSP^aa183-219 on the intracellular activity of Smad protein through binding to integrin β6. Methods: Immunofluorescence and western blot assay were used to detect the expression levels of Smad1/5/8 and phospho-Smad1/5/8 protein in the odontoblasts after treated with DSP^aa183-219 fragments. Anti-β6 antibody was used to inhibit integrin β6, and immunofluorescence and western blot assay were used to determine the expression pattern of Smad1/5/8 protein in the odontoblasts after treated with DSP^aa183-219 fragments. Results: After stimulated by DSP^aa183-219 fragments, phosphorylated-Smad1/5/8 in the odontoblasts was up-regulated and translocated to the nucleus. After treated with integrin β6 inhibitor (anti-β6 antibody), and followed by adding DSP^aa183-219 to the medium for different time periods, phosphorylation and nuclear translocation of Smad1/5/8 in the odontoblasts induced by DSP^aa183-219 were effectively blocked. Conclusion: DSP^aa183-219 binds to integrin β6 on the cell surface and induces Smad1/5/8 phosphorylation and nuclear translocation in the odontoblasts.

Key words: Dentin sialoprotein Integrin β6, Smad protein, Phosphorylation