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

TitleDissection of K+ currents in Caenorhabditis elegans muscle cells by genetics and RNA interference.
Publication TypeJournal Article
Year of Publication2003
AuthorsSanti, CM, Yuan, A, Fawcett, G, Wang, Z-W, Butler, A, Nonet, ML, Wei, A, Rojas, P, Salkoff, L
JournalProc Natl Acad Sci U S A
Volume100
Issue24
Pagination14391-6
Date Published2003 Nov 25
ISSN0027-8424
KeywordsAnimals, Animals, Genetically Modified, Caenorhabditis elegans, Caenorhabditis elegans Proteins, Genes, Helminth, Membrane Transport Proteins, Muscles, Mutation, Potassium Channels, Potassium Channels, Voltage-Gated, RNA Interference, Shaker Superfamily of Potassium Channels, Shal Potassium Channels
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.

DOI10.1073/pnas.1935976100
Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID14612577
PubMed Central IDPMC283602
Grant ListR01 GM067154 / GM / NIGMS NIH HHS / United States
R24 RR017342 / RR / NCRR NIH HHS / United States
R01 GM067154-01A1 / GM / NIGMS NIH HHS / United States
R24 RR017342-01 / RR / NCRR NIH HHS / United States