Figure 4.
Active Vinculin Holds Integrin in an Active Conformation
(A and B) Expression of vinT12 or vin880, but not vinFL, in MEFvin−/− cells increases the maximal detachment force and working energy when compared to control cells. (A schematic of the experimental setup is in Figure S4A.)
(C) U2-OS cells were seeded on poly-D-lysine to hold them in a nonspread and tensionless shape. Note the increase in antibody staining for activated β1-integrins (12G10) upon expression of vin258, vin880, and vinT12 compared to control cells expressing vinFL (Movie S4). Scale bar represents 5 μm.
(D and E) Quantification of the intensity of 12G10 labeling under control conditions (D) and after addition of Y-27632 (E).
(F) Quantification of total β1-integrin labeling under indicated conditions, using an antibody that binds to all conformations of β1-integrins (K20). All quantifications are expressed as ratios over the vinFL sample in the same condition (p < 0.01; ±SEM, n ≥ 15 cells from two independent experiments per condition).