β1 integrin redistributes to focal adhesion upon stimulation by matrix-bound VEGF₁₆₅. HUVECs treated at the conditions indicated for 15 min were fixed and stained for β1 integrin (red), paxillin (green), and TOPRO3 (blue). Arrows (A and B) indicate colocalization of β1 integrin and paxillin, arrowheads in B show focal adhesions without β1 integrin–positive staining. Asterisks in A indicate cells with higher expression of β1 integrin, to indicate that regardless of the diffused expression of β1 integrin only, Vb, but not Vs, resulted in redistribution of the integrin to focal adhesions. (A) Lower magnification; (B) higher magnification of independent experiments.