Heterozygous and homozygous hα1β2γ2S(R43Q) receptors had reduced surface expression on HEK293-T cells. A, B, HEK293-T cells transfected with wild-type (wt) or heterozygous (het) or homozygous (hom) hα1β2γ2S(R43Q) receptors were biotinylated and immunoblotted with antibodies against the α1 subunit (A) and GFP variant EYFP (B). Expression of heterozygous or homozygous α1β2γ2S(R43Q) receptors resulted in similar levels of whole-cell protein expression (total) but reduced cell surface protein expression (surface) compared with wild-type receptors. C, HEK293-T cells transfected with wild-type or heterozygous or homozygous α1β2S(R43Q) receptors and pECFP-Mem were biotinylated, and whole-cell protein was precipitated with antibody against the human α1 subunit and detected by antibody against the γ2 subunit. Heterozygous and homozygous α1β2γ2S(R43Q) receptors revealed a similar protein expression in whole-cell level (total) but a reduced protein expression in the cell surface (surface). β-Actin was used as a control to demonstrate that equal amounts of protein were loaded (β-actin). Similarly, pECFP-Mem protein expression was also similar in each group (pECFP-Mem). D, The optical absorbency of Western blots was quantified with Bio-Rad QuantifyOne. In each group, heterozygous protein intensities were lower than wild type but higher than homozygous receptors (^*p < 0.05 vs wild type; ^†p < 0.05 vs heterozygous; data are from 5 experiments).