Subunit stoichiometry of cyclic nucleotide-gated channels and effects of subunit order on channel function.
Neuron
; 16(5): 983-90, 1996 May.
Article
em En
| MEDLINE
| ID: mdl-8630256
ABSTRACT
Cyclic nucleotide-gated (CNG) ion channels are multimeric structures containing at least two subunits. However, the total number of subunits per functional channel is unknown. To determine the subunit stoichiometry of CNG ion channels, we have coexpressed the 30 pS conductance bovine retinal channel (RET) with an 85 pS conductance chimeric retinal channel containing the catfish olfactory channel P region (RO133). When RO133 and RET monomers are coexpressed, channels with four distinct intermediate conductances are observed. Dimer constructs reveal that two of these conductance levels arise from channels with the same subunit composition (2 RO1332 RET) but distinct subunit order (like subunits adjacent to each other versus like subunits across from each other). Thus, the data demonstrate that cyclic nucleotide-gated ion channels are tetrameric like the related voltage-gated potassium ion channels; the order of subunits affects the conductance of the channel; and the channel has 4-fold symmetry in which four asymmetric subunits assemble head to tail around a central axis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ativação do Canal Iônico
/
Canais Iônicos
Limite:
Animals
Idioma:
En
Ano de publicação:
1996
Tipo de documento:
Article