Induction of actin remodeling by anti-PECAM/NCs is inhibited in REN cells expressing isoforms lacking tyrosine 686. (A) Transfected and nontransfected REN cells were incubated either in the absence (−) or presence (+) of anti-PECAM/NCs for 15 minutes at 37°C, washed, fixed, and stained with Alexa Fluor 594 phalloidin to label filamentous actin. PECAM-1-negative REN cells were used as a control. Magnification bar represents 10 μm. (B) Quantification of fluorescent phalloidin indicative of filamentous actin, expressed as fold increase of fluorescence for each cell line after induction by anti-PECAM/NCs. Data are mean plus or minus SEM (n ≥ 10 cells; *P < .0001).