Figure 5.

Effect of APS1 patient and control IgG on the response of the CaSR to Ca²⁺ stimulation by measuring ERK1/2 phosphorylation. Changes in ERK1/2 phosphorylation were measured in response to no Ca²⁺ and Ca²⁺ at 0.5, 1.5, 3.0, and 5.0 mm in HEK293-CaSR cells preincubated with either APS1 patient (n = 2) or control (n = 2) IgG samples at a 1:20 dilution. The phosphorylation of ERK1/2 was measured according to a CASE Kit as in Patients and Methods. The results show the mean ratio of ERK1/2 phosphorylation (±sd) of three experiments for preincubation of HEK293-CaSR cells with IgG from APS1 patients APS1-2 and APS1-15, IgG from two controls and no IgG.