Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Biochemical and Biophysical Research Communications |
| Vol/bind | 341 |
| Udgave nummer | 4 |
| Sider (fra-til) | 979-88 |
| Antal sider | 9 |
| ISSN | 0006-291X |
| DOI | |
| Status | Udgivet - 2006 |
Bibliografisk note
Keywords: Aldosterone; Animals; Anthracenes; CHO Cells; Colon; Cricetinae; Cricetulus; KCNQ1 Potassium Channel; Kidney; Male; Membrane Potentials; Membrane Proteins; Microscopy, Confocal; Oocytes; Potassium Channels, Voltage-Gated; Rats; Xenopus laevisAdgang til dokumentet
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I: Biochemical and Biophysical Research Communications, Bind 341, Nr. 4, 2006, s. 979-88.
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - The corticosteroid hormone induced factor: a new modulator of KCNQ1 channels?
AU - Jespersen, Thomas
AU - Grunnet, Morten
AU - Rasmussen, Hanne B
AU - Jørgensen, Nils B
AU - Jensen, Henrik
AU - Angelo, Kamilla
AU - Olesen, Søren-Peter
AU - Klaerke, Dan A
N1 - Keywords: Aldosterone; Animals; Anthracenes; CHO Cells; Colon; Cricetinae; Cricetulus; KCNQ1 Potassium Channel; Kidney; Male; Membrane Potentials; Membrane Proteins; Microscopy, Confocal; Oocytes; Potassium Channels, Voltage-Gated; Rats; Xenopus laevis
PY - 2006
Y1 - 2006
N2 - The corticosteroid hormone induced factor (CHIF) is a member of the one-transmembrane segment protein family named FXYD, which also counts phospholemman and the Na,K-pump gamma-subunit. Originally it was suggested that CHIF could induce the expression of the I(Ks) current when expressed in Xenopus laevis oocytes, but recently CHIF has attracted attention as a modulatory subunit of the Na,K-pump. In renal and intestinal epithelia, the expression of CHIF is dramatically up-regulated in response to aldosterone stimulation, and regulation of epithelial ion channels by CHIF is an attractive hypothesis. To study a potential regulatory effect of the CHIF subunit on KCNQ1 channels, co-expression experiments were performed in Xenopus laevis oocytes and mammalian CHO-K1 cells. Electrophysiological characterization was obtained by two-electrode voltage-clamp and patch-clamp, respectively. In both expression systems, we find that CHIF drastically modulates the KCNQ1 current; in the presence of CHIF, the KCNQ1 channels open at all membrane potentials. Thereby, CHIF is the first accessory subunit shown to be capable of modulating both the Na,K-pump and an ion channel. To find a possible physiological function of the constitutively open KCNQ1/CHIF complex, the precise localization of KCNQ1 and CHIF in distal colon and kidney from control and salt-depleted rats was determined by confocal microscopy. However, in these tissues, we did not detect an obvious overlap in expression between KCNQ1 and CHIF. In conclusion, the hormone-regulated subunit CHIF modulates the voltage sensitivity of the KCNQ channels, but so far evidence for an actual co-localization of CHIF and KCNQ1 channels in native tissue is lacking.
AB - The corticosteroid hormone induced factor (CHIF) is a member of the one-transmembrane segment protein family named FXYD, which also counts phospholemman and the Na,K-pump gamma-subunit. Originally it was suggested that CHIF could induce the expression of the I(Ks) current when expressed in Xenopus laevis oocytes, but recently CHIF has attracted attention as a modulatory subunit of the Na,K-pump. In renal and intestinal epithelia, the expression of CHIF is dramatically up-regulated in response to aldosterone stimulation, and regulation of epithelial ion channels by CHIF is an attractive hypothesis. To study a potential regulatory effect of the CHIF subunit on KCNQ1 channels, co-expression experiments were performed in Xenopus laevis oocytes and mammalian CHO-K1 cells. Electrophysiological characterization was obtained by two-electrode voltage-clamp and patch-clamp, respectively. In both expression systems, we find that CHIF drastically modulates the KCNQ1 current; in the presence of CHIF, the KCNQ1 channels open at all membrane potentials. Thereby, CHIF is the first accessory subunit shown to be capable of modulating both the Na,K-pump and an ion channel. To find a possible physiological function of the constitutively open KCNQ1/CHIF complex, the precise localization of KCNQ1 and CHIF in distal colon and kidney from control and salt-depleted rats was determined by confocal microscopy. However, in these tissues, we did not detect an obvious overlap in expression between KCNQ1 and CHIF. In conclusion, the hormone-regulated subunit CHIF modulates the voltage sensitivity of the KCNQ channels, but so far evidence for an actual co-localization of CHIF and KCNQ1 channels in native tissue is lacking.
U2 - 10.1016/j.bbrc.2006.01.046
DO - 10.1016/j.bbrc.2006.01.046
M3 - Journal article
C2 - 16476578
SN - 0006-291X
VL - 341
SP - 979
EP - 988
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -