Membrane dissociation of PH-PLCδ1 in response to carbachol (CCh). (A) CHO-M1 cells expressing single or tandem PH domains either before or at the indicated times after addition of 1 mM CCh. Bar, 10 µm. (B) Normalized cytosolic fluorescence intensity for the cells shown in A; CCh was added at time 0. Data are fitted to a single exponential association (red lines). (C) Before addition of CCh, cells were subjected to a spot-bleach experiment. τ values for PH-PH-GFP are significantly greater than PH-GFP (P < 0.0001, Mann-Whitney test) by bleaching or after CCh addition, but were not different between methods for either PH-GFP (P = 0.85, paired test) or GFP-PH-PH (P = 0.13). Data are means ± SEM.