Degradation of Internalized αvβ5 Integrin Is Controlled by uPAR Bound uPA: Effect on β1 Integrin Activity and α-SMA Stress Fiber Assembly
Figure 6
Cell-surface integrin β1 binding to collagen is increased after uPA-silencing but β1 activation is decreased.
(A) HCFs were transfected with uPA siRNA or control siRNA. After 24 hours HCF were crosslinked to collagen. After cells were removed with 0.1% SDS, matrix-bound cross-linked proteins were released and equal amounts of protein were analyzed for integrins β5 and β1 by Western blot. (B) Cell adhesion: HCFs were transfected with uPA siRNA. After 24 hours cells were detached and seeded with blocking antibody to β5, β1 or control IgG. After 1 hour, adherent cells were quantified. **p value<0.01. (C–F) HCFs were transfected with either uPA siRNA or control siRNA and cells were analyzed after 24 hours. (C) Cell-surface biotinylation for integrin β1.(D) RT-PCR for uPA and integrin β1, *p value<0.05 and ***p value<0.001. (E) Flow cytometry for integrin β1. (F) Flow cytometry for activated integrin β1. N = 3–5 for each experiment.