Effects of the α4 tail mutations on cell migration in microchannels. (A) The migration speed and velocity of CHO-α4WT, CHO-α4Y991A, and CHO-α4S988A cells through 50- or 6-µm microchannels as a function of VCAM-1–coating concentration. Data represent means ± SEM of >20 cells from three independent experiments. (B and C) The influence of channel width on cell migration velocity through microchannels coated with 1 µg/ml VCAM-1 (B) or 5 µg/ml fibronectin (FN; C). Data represent means ± SEM of >30 cells from three independent experiments. In B, the images of migrating cells in designated channel widths and time points are also shown. White arrowheads show the centroid of cell body. *, P < 0.005 relative to CHO-α4WT.