Change in CIB localization as platelets undergo morphologic changes on immobilized Fg. Immunofluorescence staining of washed platelets that were allowed to spread on Fg for various periods of time. Platelets were then fixed and immunostained for CIB (red; upper row) and F-actin (green; middle row). The bottom row shows the merged confocal image. Images are representative of 4 different progressive stages of platelet spreading on Fg. Original magnification, × 1600.