Integrin engagement in MK adhesion to type I collagen. (A) Subcellular localization of cFN (red), CD49e (green, top panel), CD49b (green, bottom panel) in MK spread on type I collagen. Colocalization between cFN and the receptor components was analyzed by merging images obtained in green and red channels in each confocal optical section (composite). In the right panels, image magnification shows protein colocalization on the MK plasma membrane (yellow staining, arrows). All slides were also incubated with Hoechst 33288 for nuclear staining (blue). Scale bar = 10 μm. (B) Effect of RGDS, CD49e, and CD49d antibodies and their combination on MK spreading upon incubation for 16 hours. Results are reported as a percentage of inhibitor-treated MKs adherent to collagen type I compared with MKs treated with PBS alone, and are the means ± SD of 3 different experiments. *P < .05.