Fig. 2.

CCL19, but not CCL21, leads to ß-arrestin2 trafficking to endocytic vesicles and desensitization. (A) HEK-293 cells were transiently transfected with CCR7 and ß-arrestin2-GFP. Cells were left unstimulated or stimulated with 100 nM CCL19 or 100 nM CCL21 for 1 h. Live cells were imaged by confocal microscopy, and representative images from three independent experiments are shown. (B) HEK-293 cells stably expressing CCR7 and the cAMP biosensor ICUE2 were pretreated with 100 nM CCL19 or 100 nM CCL21 for 1 h as indicated. Cells were washed and stimulated with forskolin alone (50 μM) or 100 nM CCL21 + forskolin. The bar graft shows cAMP responses as measured by the integrated ICUE2 FRET after 10 min. Statistical significance was determined by paired two-tailed t tests. **, P < 0.01.