Discoidin Domain Receptors Promote α1β1- and α2β1-Integrin Mediated Cell Adhesion to Collagen by Enhancing Integrin Activation
Figure 3
Cell spreading on collagen I, integrin ligand GFOGER or DDR ligand GVMGFO.
293-DDR1 cells (A) or 293-DDR2 cells (B) were allowed to adhere to substrate-coated ibidi dishes as described in Materials and Methods. Cell spreading was observed using interference reflection microscopy (IRM) to view the attachment sites between the cell membrane and the substrate. (A) and (B): Reflective images show the footprint of cell-substrate contact areas (upper panels). The bright field images show intact cells (lower panels). White bars, 10 µm. The data are representative of three independent experiments, in which 3–6 independent optical fields were taken. (C) Quantification of contact area showing the means ± SEM of 20–45 cells for each condition. Statistical analysis was performed using unpaired, two tailed, T-test with unequal variances, and statistical significance was defined as P<0.05 (*), P<0.01 (**), and P<0.001 (***).