FcϵRI Complexes are Better with Beta

Science's STKE  06 Jun 2000:
Vol. 2000, Issue 35, pp. tw4
DOI: 10.1126/stke.2000.35.tw4

The FcϵRI complex exists in two forms composed of α and γ subunits in the presence or absence of β subunits: αγ2, and αβγ 2. The presence of the β subunit in FcϵRI increases the transduced signal to approximately 5 times that of β-deficient FcϵRIs. Donnadieu et al. uncover another method by which β subunits increase FcϵRI signal amplification: increasing the amounts of α subunit found at the plasma membrane. Cells stably expressing the αγ 2 receptor express higher levels of functional FcϵRI when also transfected with the β chain. Expression of the β chain in αγ 2 cells led to increased maturation of α, and the authors also demonstrated that α and β associate early in the ER compartment. Additionally, the stability of the functional FcϵRI complex, as measured by protein-protein associations within immune complexes, is increased in the presence of the β chain. Thus, the presence of the β chain in FcϵRI appears to increase receptor density and receptor stability and suggests that the different FcϵRI isoforms may have specific roles in differing cell types.

Donnadieu, E., Jouvin, M.-H., and Kinet, J.-P. (2000) A second amplifier function for the allergy-associated FcϵRI-β subunit. Immunity 12: 515-523. [Online Journal]