Extended Data Fig. 1: Receptor-binding studies of SST treated with and without metal ions.
a, Titration experiments to determine the EC50 value of the GRABSST sensor against SST. Various concentrations of SST were sequentially added to the GRABSST sensor-expressing HEK293T cells at a 1 min interval. The ΔF/F0 values were plotted as a function of log[SST] and fitted to obtain the EC50 value. Data are presented as mean ± s.e.m. (standard error of the mean); n = 9. Conditions: [SST] = 0.003, 0.01, 0.03, 0.05, 0.1, 0.3, 0.5, 1, 3, and 7 μM; 20 mM HEPES, pH 7.4, 150 mM NaCl. b, Change in the fluorescence intensity of the GRABSST sensor upon addition of SST incubated with or without metal ions. Data are presented as mean ± s.e.m. (standard error of the mean); n = 20 (without metal ions), n = 10 (with metal ions). c, Fluorescence measurements of the GRABSST sensor after administration of metal ions and vehicle (buffered solution). Data are presented as mean ± s.e.m. (standard error of the mean); n = 4–10 per group. Conditions: [SST] = 0.5 μM; [MCl2] = 0.5 μM; 20 mM HEPES, pH 7.4, 150 mM NaCl; 24 h incubation; constant agitation. The vertical lines indicate time points when the ΔF/F0 values were quantitatively analyzed and compared between groups.
