Growth of cells on fibronectin alters polarization of cell surface molecules.

CAG cells were grown on fibronectin-coated chamber slides, stained against ICAM-1 or syndecan-1, fixed, and photographed through an inverted phase contrast or a fluorescence microscope. The phase contrast image (A) shows cell morphology with filopodia extending from the uropods. Cells in picture (B) (same field as A) are stained against ICAM-1 and cells in pictures (C-D) against syndecan-1. Both these molecules are polarized to an area located on the cell body at the neck of the uropod. (E-F) show syndecan-1 expression in uropods pointing toward the outer environment. In (E), the microscope is focused on the interface between the glass surface and the cells and the syndecan hotspots in the uropods appear blurred. (F) shows the same cells as in (E) with the focal plane elevated some 10 μm above the slide surface. Syndecan is now in focus, showing that the uropods are oriented upward.