The Fc receptor (FcR) gamma subunit was originally discovered as a homodimeric subunit of the high-affinity IgE receptor (FcepsilonRI). But it was recently found to be a common signal-generating subunit of Fc receptors including IgG Fc receptors (FcgammaRs) and IgA Fc receptor (FcalphaR), and furthermore to generate a signal also with stimuli through non-immune receptors. In addition, it plays an essential role in cell-surface expression of the FcepsilonRI and the FcgammaRIIIA isoform and also regulates cell-surface expression and ligand-binding affinity of the FcgammaRI. In this report, we addressed the possibility that the FcRgamma could affect the correct folding of the IgE-binding region of the FcepsilonRIalpha subunit by using the chimeric receptor molecules constructed from human FcepsilonRIalpha and FcRgamma. Furthermore, we demonstrated that the seven amino acid residues in the C-terminal region on the extracellular domain of the FcepsilonRlalpha were essential for maintaining the IgE-binding activity of the FcepsilonRIalpha exodomain on the cell membrane and/or may affect the correct folding of the alpha subunit itself within the cell.