Laser scanning confocal microscopy analysis revealed CD9 colocalized with integrin α5β1, but not all integrin subunit β1, on the basal surface of subconfluent FN-adherent CHO A6 cells.
Cell cycle–synchronized CHO A6 cells were grown on FN-coated slides for 3 hours, as described in “Materials and methods.” (A) mAb7-labeled CD9 (green) and PB1-labeled α5β1 (red) were located in punctate clusters (large arrows), particularly at the cell margin (arrowheads) and along filipodia. Colocalization of CD9 and α5β1 (yellow) was nearly total. Note the CD9-integrin α5β1–deficient zone just inside the cell margin (small arrows). (B) mAb7-labeled CD9 (green) and 7E2-labeled integrin subunit β1(red) were found in punctate patches, particularly at the cell margin (large arrows) on the basal surface. Most integrin β1colocalized (yellow) with CD9. However, the zone just inside the cell margin previously described as CD9 and integrin subunit α5β1-free contained integrin subunit β1 not colocalized with CD9. Original magnification × 100.
