Summary of cellular responses of HEK293 cells transiently transfected with WT CaSR or disease related mutants.

The average levels of [Ca2+]o at which cells started to exhibit [Ca2+]i oscillations were recorded for WT or each mutant CaSR. For the oscillation frequencies in the absence of L-Phe, peaks per minute were measured at the level of [Ca2+]o at which more than 50% cells started to oscillate; when L-Phe was added, frequencies were recorded at the same [Ca2+]o as their counterparts without L-Phe. Specifically, the frequencies of WT was measured at 3.0 mM [Ca2+]o, at 2.5 mM [Ca2+]o for L173F and P221L; at 15.0 mM [Ca2+]o for L173Pand at 5.0 mM [Ca2+]o for P221Q. Curve-fitting was performed using the Hill equation. The data were obtained from three experiments for each construct. Values are means ± S.E. EC50 and Hill numbers obtained from the cell population assay by fitting plots using the Hill equation. # indicates significance with respect to wild type CaSR in the absence of L-Phe, p* indicates significance with respect to the corresponding mutants in the absence of L-Phe, pSummary of cellular responses of HEK293 cells transiently transfected with WT CaSR or disease related mutants.