Figure 4.

Cell rear is detached for upstream-bound cells and cell front for downstream-bound cells. Shown is the representative image sequence of crawling cells under a flow of 8 dyn/cm⁻² in phase contrast (top) and reflection interference contrast microscopy (RICM) (center). On the merged images, the RICM image is contrast inverted and colored in red. The black arrow indicates flow direction, and the white arrow indicates the direction of cell migration. The adhesion zone (dark in RICM, red in merge) is positioned in cell front for upstream crawling cells and in cell rear for downstream crawling cells. Scale bars, 10 μm. To see this figure in color, go online.