Fig. 4. High-affinity mutants of β3 integrin fail to stimulate RhoA activity and fibronectin fibrillogenesis. (A) Images of β1-integrin-deficient GE11 cells expressing indicated β3 integrin affinity mutants stained for paxillin (green), F-actin (red) and the nucleus (blue). Scale bar: 10 µm. (B) Western blot analysis of RhoA activity assay on lysates of GE11 cells expressing indicated constructs. Quantification shows relative RhoA activation ± s.d. compared with GEβ1 cells from two experiments. (C) Western blot analysis of assembled fibronectin-biotin and vimentin (loading control) in DOC-insoluble lysates of GE11 cells expressing indicated constructs.