Table 3.

Effects of FHH3-associated AP2S1 mutation (Arg15Cys) on CaSR cell-surface expression.

	Total CaSR		Cell-surface CaSR
	0.5mM Ca2+	5mM Ca2+	0.5mM Ca2+	5mM Ca2+
Vector	100±1.4	101.9±2.3	100±4.9	47.1±3.6a*
WT (Arg15)	99.3±2.8	104.6±0.9	93±4.2	28.1±2.0b*,d*,e#
Mutant (Cys15)	92.6±1.3	98.6±2.3	98.1±2.8	47.1±6.3c*

HEK293 cells which stably expressed the CaSR were transfected with WT (Arg15) AP2S1, mutant (Cys15) AP2S1 or vector-only constructs, treated with either 0.5mM Ca²⁺_o or 5.0mM Ca²⁺_o for 15 minutes, and cell-surface and total expression of CaSR measured using an intact cell ELISA¹⁸. Results were normalised to vector-only transfected cells, as previously reported¹⁸, and shown as mean±SEM (n=6) for each experiment. Comparison of total CaSR at 0.5mM and 5mM revealed no significant difference. Comparison of cell-surface CaSR expression revealed significant differences as follows:

^aCompared to Vector (0.5mM);

^bCompared to WT (0.5mM);

^cCompared to Mutant (0.5mM);

^dCompared to Vector (5mM);

^eCompared to Mutant (5mM).

^*p<0.005,

^#p<0.05.