Fig. 5: L-AA binding is required for the basal activity of CSCS.
From: Absence of calcium-sensing receptor basal activity due to inter-subunit disulfide bridges
a View of the six residues involving in the L-Trp binding in the CaSR structure (PDB: 7DTW). b Basal IP1 accumulation measured for the WT and indicated mutants (n = 5). c Basal IP1 accumulation for the WT and the indicated mutants in the presence of increasing concentrations of Trp under conditions without or with three wash steps over a 3-h period (n = 9). d Cartoons illustrating the mechanism of only the homodimer formed by the CaSRC1 and CaSRC2 subunits could reach the cell surface. e Basal IP1 accumulation mediated by the indicated subunit compositions (n = 4). f Schemes illustrating how the mutations of the glutamate binding pocket (S170A) in the CaSRC1-C2 homodimer impair the basal activity of the receptor. Data above are mean ± SEM of at least three independent experiments performed in triplicates and normalized to the mock. Significance was analyzed using one-way ANOVA with Dunnett’s multiple comparisons with ****P ≤ 0.0001, ***P ≤ 0.001, **P ≤ 0.01, *P ≤ 0.05 and ns for P > 0.05 compared with indicated groups, and ####P ≤ 0.0001 versus the indicated CSCS construct containing no additional mutations.
