Figure 4.

cAMP-induced circumferential actin bundling does not depend upon VE-cadherin–based cell–cell adhesions. (A–D) HUVECs were transfected with control siRNA (top panels of each figure) or with siRNAs targeting against VE-cadherin (A), α-catenin (B), β-catenin (C), and p120-catenin (D) (bottom panels of each figure), cultured for 48 h, and replated onto the collagen-coated glass-base dish. After 24 h, the cells were starved in medium 199 containing 0.5% BSA for 3 h and stimulated with vehicle (control) or 10 μM FSK for 30 min as indicated at the left of each figure. The cells were stained with anti-VE-cadherin (A), anti-α-catenin (B), anti-β-catenin (C), and anti-p120-catenin (D) antibodies and visualized with Alexa 488-conjugated secondary antibody as described in Figure 2A. The cells were also stained with rhodamine-phalloidin to visualize F-actin. Alexa 488 and rhodamine images were obtained through a confocal microscope. Alexa 488 images for VE-cadherin (A), α-catenin (B), β-catenin (C), and p120-catenin (D) are shown at the left column. Rhodamine (F-actin) and the merged (merge) images are shown at the middle and right columns, respectively. The boxed areas marked by dotted line in the images are enlarged in the bottom right corner of each image. Bars, 50 μm.