Inhibition of the Arp2/3 complex leads to separation of linear AJs. (A and B) Fluorescence staining of control HUVECs (A) and HUVECs treated with 100 µM CK666 (B) with phalloidin (red) and VE-cadherin antibody (yellow). Boxed regions in A and B are enlarged at right. The asterisk marks VE-cadherin at the edge of a gap. (C and D) Two examples of GFP–VE-cadherin (green) and mCherry-LifeAct (red) dynamics at AJs in the course of CK666 treatment. CK666 was added at time 0. Arrows mark CK666-induced intercellular gaps; arrowheads mark VE-cadherin at gap edges. Bars: (A and B, left, and C and D) 10 µm; (A and B, right) 5 µm.