(A) qRT-PCR for Orai1 mRNA in LAD2 cells using five shRNA constructs targeting Orai1. (B-D) Comparison of β-hexosaminidase release from LAD2 cells transduced with scramble, shMS4A4A, shOrai1 (v2, the most effective construct) or shMS4A4A plus shOrai1 (v2). Stimulants of degranulation included biotinylated IgE with streptavidin (B), compound 48/80 (C), and thapsigargin (D). Data are the mean ± SEM from three (A) or five (B-D) independent experiments. **p<0.01, ***p<0.001, ****p<0.0001, ANOVA with Sidak’s posttest.