Fig. 8. Quantitation of cell polarization. B28 cells transfected with wild-type NG2 (clone 6) and with NG2/S1342A (clones 42 and 44) and NG2/S999A (clones 51 and 65) were compared with parental B28 cells (P) for their ability to polarize after 8 hours of spreading on PLL-coated (A) and mAb-coated dishes (B). After spreading, the cells were fixed with paraformaldehyde and stained with poly-specific anti-B28 antibody as shown in Fig. 7 to allow determination of the percentage of polarized cells. Mean and standard error values were calculated from data obtained with three replicate plates for each cell type. On PLL dishes the addition of LPA to the control BSA-containing medium stimulated polarization in wild-type and NG2/S1342A transfectants, but not in parental cells or NG2/S999A transfectants. On D120-coated dishes, wild-type and NG2/S1342A transfectants had much a greater tendency to polarize than on mAb CD44-coated dishes, whereas NG2/S999A transfectants did not distinguish significantly between the two surfaces.