SLO-2 isoforms with unique Ca(2+) - and voltage-dependence characteristics confer sensitivity to hypoxia in C. elegans.
Channels (Austin)
; 7(3): 194-205, 2013.
Article
en En
| MEDLINE
| ID: mdl-23590941
ABSTRACT
Slo channels are large conductance K (+) channels that display marked differences in their gating by intracellular ions. Among them, the Slo1 and C. elegans SLO-2 channels are gated by calcium (Ca ( 2+) ), while mammalian Slo2 channels are activated by both sodium (Na (+) ) and chloride (Cl (-) ). Here, we report that SLO-2 channels, SLO-2a and a novel N-terminal variant isoform, SLO-2b, are activated by Ca ( 2+) and voltage, but in contrast to previous reports they do not exhibit Cl (-) sensitivity. Most importantly, SLO-2 provides a unique case in the Slo family for sensing Ca ( 2+) with the high-affinity Ca ( 2+) regulatory site in the RCK1 but not the RCK2 domain, formed through interactions with residues E319 and E487 (that correspond to D362 and E535 of Slo1, respectively). The SLO-2 RCK2 domain lacks the Ca ( 2+) bowl structure and shows minimal Ca ( 2+) dependence. In addition, in contrast to SLO-1, SLO-2 loss-of-function mutants confer resistance to hypoxia in C. elegans. Thus, the C. elegans SLO-2 channels possess unique biophysical and functional properties.
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Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Proteínas de Transporte de Membrana
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Canales de Calcio
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Calcio
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Caenorhabditis elegans
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Proteínas de Caenorhabditis elegans
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Hipoxia
Tipo de estudio:
Diagnostic_studies
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Prognostic_studies
Idioma:
En
Revista:
Channels (Austin)
Año:
2013
Tipo del documento:
Article