Fig. 2.
Human lung fibroblasts express multiple integrins that recognize provisional matrix binding proteins. A: immunoprecipitation analysis of cell surface integrins in fibroblasts. Cells were surface labeled with biotin and immunoprecipitated using integrin-specific antibodies as indicated. Telative migration of the individual integrin subunits is indicated at left. Expression of integrins αvβ5 (lane 2) and αvβ3 (lane 3) was detected using heterodimeric-specific integrin antibodies. In the αv-immunoprecipitate (lane 4), bands at 160, 120, and 100 kDa were detected consistent with the αv-, β1-, and β3/β5-subunits, respectively, indicating αv pairs with β1 and β3/β5 in these cells. In the anti-β1-immunoprecipitate (lane 5), bands at 220, 160, and 120 kDa were detected, consistent with expression of the α1-, αv-, and β1-subunits, respectively, indicating expression of α1β1 and αvβ1. No expression of α8- or α9-integrins was detected (lanes 6 and 7). B: flow cytometry detection of cell surface integrin expression in fibroblasts. Cell surface expression of integrins were detected by monoclonal antibodies against integrins u-PAR (No. 3936 American Diagnostica), α1 (Mab 1973; Chemicon), α2 (clone A2-IIE10), α3 (clone P1B5), α5 (clone SAM-1), β1 (clone P4C10), αvβ3 (clone LM609), and αvβ5 (clone P1F6), and Mac-1 (Clone ICRF-44), respectively.