Fig. 1.

Internalisation of native and mutated Y receptors quantified by granularity analysis. Y1 and Y2 receptors, fused to GFP, were each stably transfected in 293TR cells, with inducible receptor expression initiated by 18 h pretreatment with tetracycline (1 μg ml^− 1). Representative example experiments (A) show images acquired by the IX Ultra confocal platereader, of cells under control conditions, or treated for 30 min with NPY at the indicated concentration. For each case, the right hand panel indicates the associated granularity analysis, which identified cells from the parallel image of H33342 stained nuclei (grey, original image not shown), together with punctate vesicular structures more than 3 μm in diameter (white dots). Internalisation was quantified as the average granule intensity/cell, normalised as a percentage of the basal measurements, and pooled to provide the concentration − response curves (n = 4) shown in (B) and (C). EC₅₀ values are quoted in the text.