EMR2/1-5 mediates cell attachment. (A) Graph showing the effects of EMR2 protein concentration on cell attachment. □ and ♦ denote EMR2/1-5 mouse Fc and EMR2/1,2 mouse Fc proteins, respectively (n = 3). Error bars are equal to one standard deviation. (B) Top row: morphology of attached CHO-K1 cells. Cells spread when incubated with fibronectin for 60 minutes. However, cells incubated only with EMR2/1-5 mouse Fc attach. Original magnification, × 400. Lower panels: confocal microscopy showing actin staining of cells attached to either fibronectin or different EMR2 protein isoforms. Original magnification, × 600.