Fig. 4. Dose response curves of PHCrac-GFP translocation and patch formation. Cells were incubated in buffer for 30 seconds, followed at t=0 seconds by perfusion with the indicated cAMP concentrations. At t=30 seconds, all cells were perfused with 1 µM cAMP. The experiment with 0.1 nM cAMP was slightly different: cells were stimulated for 45 seconds followed by the upshift. Different aspects of these responses are presented as a percentage of the maximal response: the first depletion of the fluorescence intensity in the cytosol (maximum 53%); recovery of the fluorescence intensity in the cytosol (maximum 100%); the proportion of cells with one or more patches (maximum 100%); the number of patches per cell (maximum 2.2); the fluorescence intensity of the patches (maximum 2.4); and the size of the patches (maximum 9.85 µm). The results shown are the means and standard error of the means of about 20 cells (except the size and fluorescence intensity of the patches at 0.1 nM cAMP, which were for five patches).