Figure 2

Trafficking of yeast Ste2, human β ₂ AR, and a yeast Ste2/human β ₂ AR chimera expressed in human HEK293 cells in response stimulation by insulin: analysis by confocal microscopy. HEK293 cells were transiently transfected to express either β₂AR-GFP (panels a, b), Ste2-GFP (panels c, d), or the Ste2/β₂AR-GFP chimeric receptor (panels e,f). For each of these GPCRs, localization of the receptors in the untreated cells was dominant at the cell membrane (white arrows). Cells were treated without (panels a, c, e) or with (panels b, d, f) insulin (100 nM) for 0.5 h and followed by confocal microscopy. Insulin stimulates internalization of the β₂AR-GFP (panel b) and of the Ste2/β₂AR-GFP chimeric receptor (panel f), but not of Ste2-GFP (panel d). The images displayed are from a single experiment, representative of more than five replicate, separate experiments. Bar equals 10 μm.