Alpha 5 subunit forms functional alpha 3 beta 4 alpha 5 nAChRs in transfected human cells.
nAChRs heterologously expressed in human cells after transient transfection with alpha 3 beta 4 alpha 5 or alpha 3 beta 4 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 alpha 5, alpha 3 and beta 4 subunits. One component was comparable to that obtained in alpha 3 beta 4-transfected cells, while the additional component, putatively attributed to an alpha 3 beta 4 alpha 5 nAChR population, showed a Hill coefficient > 2 and a nine-fold greater half-maximal ACh concentration (EC50). These results suggest that the alpha 5 subunit participates in the assembly of alpha 3 beta 4 alpha 5 nAChRs complexes in human cells, adding a new member to the family of neuronal nicotinic receptors.
Fucile
S
S
Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Medicina Sperimentale e Patologia, Università di Roma, Italy.
Barabino
B
B
Palma
E
E
Grassi
F
F
Limatola
C
C
Mileo
A M
AM
Alemà
S
S
Ballivet
M
M
Eusebi
F
F
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D002645:Chickens; D003001:Cloning, Molecular; D005260:Female; D018738:Hexamethonium / Q000494:pharmacology; D006801:Humans; D046911:Macromolecular Substances; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000502:physiology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D009865:Oocytes / Q000502:physiology; D011978:Receptors, Nicotinic / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis; D014162:Transfection; D014981:Xenopus
D046911:Macromolecular Substances; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D011994:Recombinant Proteins; D018738:Hexamethonium; D000109:Acetylcholine