FIGURE 4.

Confocal microscopy imaging of intracellular trafficking of internalized CCK2R. HEK cells were transfected with cDNA encoding CCK2R-GFP and Rab5-DsRed, Rab11-DsRed, or Rab7-DsRed. Images were captured at the times indicated after stimulation by CCK (0.1 μm). Arrows show predominant co-localization of CCK2R with Rab5 in early endosomes at initial steps of internalization (time 0 (To) and 1 h), whereas strong co-localization with Rab7 in late endosomes was observed at 5–6 h. Co-localization with Rab11 in recycling endosomes was observed at times longer than 2 h. Each image is representative of 5–7 observations from three separate experiments.