Fig. 6. Involvement of the Rho GTPase in cell polarization. NG2-transfected B28 cells were serum-starved overnight, resuspended in DMEM/BSA for 1 hour, then allowed to spread for 8 hours on PLL- or mAb-coated plates. Cells were then fixed with paraformaldehyde and stained with poly-specific rabbit antibody against B28 cells. The percentage of morphologically polarized cells was determined under a variety of conditions. On PLL plates the control condition was 1% BSA in DMEM, to which were added either 10 ng/ml of PDGF-AA and PDGF-BB or 1 µg/ml LPA. For mAb-coated plates the control condition is mAb CD44 coating, whereas the stimulatory condition is mAb D120 coating. When used, the C3 exoenzyme (3 µg/ml) and the Y27632 (Y) rho-associated kinase inhibitor (20 µM) were added to cells during the 1 hour suspension period and maintained in the cultures throughout the spreading phase of the experiment. Mean and standard error values for each condition were calculated from data obtained from three replicate plates.
