Figure 5. Effects of naturally occurring MRGPRX2 mutations (N16H, W243R and H259Y) on cell surface expression, Ca²⁺ mobilization and SP-induced degranulation in transiently transfected RBL cells.

(A): Flow cytometry was performed using PE-anti-MRGPRX2 antibody to determine cell surface expression of wild-type (WT) and variants in transiently transfected in RBL cells. Representative histograms for WT/Variant (thick line) and control untransfected cells (thin line) are shown. (B): Cells expressing WT and MRGPRX2 variants were loaded with Indo-1 and intracellular calcium mobilization in response to SP (1 μM) was determined. Data shown are representative of three independent experiments. (C): Cells were exposed to buffer (control) or SP (1 μM) for 30 min and β-hexosaminidase release was determined. All data points are expressed as mean ± SEM of three experiments performed in triplicate. Statistical significance was determined by two tailed unpaired t-Test. ** indicates P value <.01.