Images of cells showing localization of integrins and heterogeneity in integrin cluster size, shape, and location. Cells shown are plated on coverslips coated with: (a) 5 μg/mL Fg, (b) 20 μg/mL Fg, and (c) 100 μg/mL Fg. In (a), (b), and (c), integrin β3 is shown in red and F-actin is shown in green, and scale bars are 5 μm. (d) shows the cell from (b) following image analysis; white areas are integrin clusters, the red outline indicates the cell periphery, and the red circle identifies the cell centroid. The dotted green lines shows the distances from the cell centroid to several integrin clusters, and the dashed magenta lines show the corresponding distances from the integrin cluster to the cell periphery. The combination of the green line and the magenta line indicates the total distance from the cell centroid to the cell perimeter.