Nicotinic acetylcholine receptors assembled from the alpha7 and beta3 subunits

Article Article scientifique Article Nicotinic acetylcholine receptors assembled from the alpha7 and beta3 subunits eng 1999-06-25 author Palma Eleonora 96457 author Maggi Laura author Barabino Benedetta 126543 author Eusebio Luca Fabrizio 36006 author Ballivet Marc 24708 18335-18340 10.1074/jbc.274.26.18335 0021-9258 Intracellular recordings were performed in voltageclamped Xenopus oocytes upon injection with a mixture of cDNAs encoding the β3 and mutant α7 (L247Tα7) neuronal nicotinic acetylcholine receptor (nAChR) subunits. The expressed receptors maintained sensitivity to methyllycaconitine and to α-bungarotoxin but exhibited a functional profile strikingly different from that of the homomericL247Tα7 receptor. The heteromericL247T α7 β3 nAChR had a lower apparent affinity and a faster rate of desensitization than L247Tα7 nAChR, exhibited nonlinearity in the I-V relationship, and was inhibited by 5-hydroxytryptamine, much like wild type α7 (WT α7) nAChR. Single channel recordings in cell-attached mode revealed unitary events with a slope conductance of 19 picosiemens ans a lifetime of 5 ms, both values being much smaller than those of the homomeric receptor channel. Upon injection with a mixture of WTα7 and β3 cDNAs, clear evidence was obtained for the plasma membrane assembly of heteromeric nAChRs, although ACh could not activate these receptors. It is concluded that β3, long believed to be an orphan subunit, readily co-assembles with other subunits to form heteromeric receptors, some of which may be negative regulators of cholinergic function. Dewey 540 39 Département de biochimie 144 false The Journal of biological chemistry 274 26 ba120abc-743c-4ae2-b2a7-561d13e61f9d Article (Published version) Public PALMA_TJBC_183401999.pdf 266953 application/pdf CC BY openAccess Faculté des sciences / Section de chimie et biochimie / Département de biochimie

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Nicotinic acetylcholine receptors assembled from the alpha7 and beta3 subunits	The Journal of biological chemistry			1999	151	99

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Eusebio, Luca Fabrizio