Dissection of K+ currents in Caenorhabditis elegans muscle cells by genetics and RNA interference

Santi, CM; Yuan, A; Fawcett, G; Wang, ZW; Butler A.; *Nonet ML; Weiß A.; Rojas P.; Salkoff, L

Abstract

GFP-promoter experiments have previously shown that at least nine genes encoding potassium channel subunits are expressed in Caenorhabditis elegans muscle. By using genetic, RNA interference, and physiological techniques we revealed the molecular identity of the major components of the outward K + currents in body wall muscle cells in culture. We found that under physiological conditions, outward current is dominated by the products of only two genes, Shaker (Kv1) and Shal (Kv4), both expressing voltage-dependent potassium channels. Other channels may be held in reserve to respond to particular circumstances. Because GFP-promoter experiments indicated that slo-2 expression is prominent, we created a deletion mutant to identify the SLO-2 current in vivo. In both whole-cell and single-channel modes, in vivo SLO-2 channels were active only when intracellular Ca2+ and Cl- were raised above normal physiological conditions, as occurs during hypoxia. Under such conditions, SLO-2 is the largest outward current, contributing up to 87% of the total current. Other channels are present in muscle, but our results suggest that they are unlikely to contribute a large outward component under physiological conditions. However, they, too, may contribute currents conditional on other factors. Hence, the picture that emerges is of a complex membrane with a small number of household conductances functioning under normal circumstances, but with additional conductances that are activated during unusual circumstances.

Más información

Título según WOS: Dissection of K+ currents in Caenorhabditis elegans muscle cells by genetics and RNA interference
Título según SCOPUS: Dissection of K+ currents in Caenorhabditis elegans muscle cells by genetics and RNA interference
Título de la Revista: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volumen: 100
Número: 24
Editorial: NATL ACAD SCIENCES
Fecha de publicación: 2003
Página de inicio: 14391
Página final: 14396
Idioma: English
URL: http://www.pnas.org/cgi/doi/10.1073/pnas.1935976100
DOI:

10.1073/pnas.1935976100

Notas: ISI, SCOPUS