α5 Subunit forms functional α3β4α5 nAChRs in transfected human cells

Abstract
NACHRS heterologously expressed in human cells after transient transfection with α3β4α5 or α3β4 subunit cDNAs exhibited similar sensitivities to antagonists and comparable functional channel profiles. However, the sum of two Hill equations was required for best fitting the ACh dose—current response curves after co-expression of α5, α3 and β4 subunits. One component was comparable to that obtained in α3β4-transfected cells, while the additional component, putatively attributed to an α3β4α5 nAChR population, showed a Hill coefficient > 2 and a nine-fold greater half-maximal ACh concentration (EC50). These results suggest that the α5 subunit participates in the assembly of α3β4α5 nAChRs complexes in human cells, adding a new member to the family of neuronal nicotinic receptors.