Sexual dimorphism and oestrogen regulation of KCNE3 expression modulates the functional properties of KCNQ1 K channels.

Hdl Handle:
http://hdl.handle.net/10147/207347
Title:
Sexual dimorphism and oestrogen regulation of KCNE3 expression modulates the functional properties of KCNQ1 K channels.
Authors:
Alzamora, Rodrigo; O'Mahony, Fiona; Bustos, Viviana; Rapetti-Mauss, Raphael; Urbach, Valerie; Cid, L Pablo; Sepulveda, Francisco V; Harvey, Brian J
Affiliation:
Department of Molecular Medicine, Education and Research Centre, Royal College of, Surgeons in Ireland, Beaumont Hospital, Dublin, Republic of Ireland.
Citation:
J Physiol. 2011 Nov 1;589(Pt 21):5091-107. Epub 2011 Sep 12.
Journal:
The Journal of physiology
Issue Date:
1-Feb-2012
URI:
http://hdl.handle.net/10147/207347
DOI:
10.1113/jphysiol.2011.215772
PubMed ID:
21911611
Abstract:
The KCNQ1 potassium channel associates with various KCNE ancillary subunits that drastically affect channel gating and pharmacology. Co-assembly with KCNE3 produces a current with nearly instantaneous activation, some time-dependent activation at very positive potentials, a linear current-voltage relationship and a 10-fold higher sensitivity to chromanol 293B. KCNQ1:KCNE3 channels are expressed in colonic crypts and mediate basolateral K(+) recycling required for Cl(-) secretion. We have previously reported the female-specific anti-secretory effects of oestrogen via KCNQ1:KCNE3 channel inhibition in colonic crypts. This study was designed to determine whether sex and oestrogen regulate the expression and function of KCNQ1 and KCNE3 in rat distal colon. Colonic crypts were isolated from Sprague-Dawley rats and used for whole-cell patch-clamp and to extract total RNA and protein. Sheets of epithelium were used for short-circuit current recordings. KCNE1 and KCNE3 mRNA and protein abundance were significantly higher in male than female crypts. No expression of KCNE2 was found and no difference was observed in KCNQ1 expression between male and female (at oestrus) colonic crypts. Male crypts showed a 2.2-fold higher level of association of KCNQ1 and KCNE3 compared to female cells. In female colonic crypts, KCNQ1 and KCNE3 protein expression fluctuated throughout the oestrous cycle and 17beta-oestradiol (E2 10 nM) produced a rapid (<15 min) dissociation of KCNQ1 and KCNE3 in female crypts only. Whole-cell K(+) currents showed a linear current-voltage relationship in male crypts, while K(+) currents in colonic crypts isolated from females displayed voltage-dependent outward rectification. Currents in isolated male crypts and epithelial sheets were 10-fold more sensitive to specific KCNQ1 inhibitors, such as chromanol 293B and HMR-1556, than in female. The effect of E2 on K(+) currents mediated by KCNQ1 with or without different beta-subunits was assayed from current-voltage relations elicited in CHO cells transfected with KCNQ1 and KCNE3 or KCNE1 cDNA. E2 (100 nM) reduced the currents mediated by the KCNQ1:KCNE3 potassium channel and had no effect on currents via KCNQ1:KCNE1 or KCNQ1 alone. Currents mediated by the complex formed by KCNQ1 and the mutant KCNE3-S82A beta-subunit (mutation of the site for PKCdelta-promoted phosphorylation and modulation of the activity of KCNE3) showed rapid run-down and insensitivity to E2. Together, these data suggest that oestrogen regulates the expression of the KCNE1 and KCNE3 and with it the gating and pharmacological properties of the K(+) conductance required for Cl(-) secretion. The decreased association of the KCNQ1:KCNE3 channel complex promoted by oestrogen exposure underlies the molecular mechanism for the sexual dimorphism and oestrous cycle dependence of the anti-secretory actions of oestrogen in the intestine.
Language:
eng
ISSN:
1469-7793 (Electronic); 0022-3751 (Linking)

Full metadata record

DC FieldValue Language
dc.contributor.authorAlzamora, Rodrigoen_GB
dc.contributor.authorO'Mahony, Fionaen_GB
dc.contributor.authorBustos, Vivianaen_GB
dc.contributor.authorRapetti-Mauss, Raphaelen_GB
dc.contributor.authorUrbach, Valerieen_GB
dc.contributor.authorCid, L Pabloen_GB
dc.contributor.authorSepulveda, Francisco Ven_GB
dc.contributor.authorHarvey, Brian Jen_GB
dc.date.accessioned2012-02-01T10:05:23Z-
dc.date.available2012-02-01T10:05:23Z-
dc.date.issued2012-02-01T10:05:23Z-
dc.identifier.citationJ Physiol. 2011 Nov 1;589(Pt 21):5091-107. Epub 2011 Sep 12.en_GB
dc.identifier.issn1469-7793 (Electronic)en_GB
dc.identifier.issn0022-3751 (Linking)en_GB
dc.identifier.pmid21911611en_GB
dc.identifier.doi10.1113/jphysiol.2011.215772en_GB
dc.identifier.urihttp://hdl.handle.net/10147/207347-
dc.description.abstractThe KCNQ1 potassium channel associates with various KCNE ancillary subunits that drastically affect channel gating and pharmacology. Co-assembly with KCNE3 produces a current with nearly instantaneous activation, some time-dependent activation at very positive potentials, a linear current-voltage relationship and a 10-fold higher sensitivity to chromanol 293B. KCNQ1:KCNE3 channels are expressed in colonic crypts and mediate basolateral K(+) recycling required for Cl(-) secretion. We have previously reported the female-specific anti-secretory effects of oestrogen via KCNQ1:KCNE3 channel inhibition in colonic crypts. This study was designed to determine whether sex and oestrogen regulate the expression and function of KCNQ1 and KCNE3 in rat distal colon. Colonic crypts were isolated from Sprague-Dawley rats and used for whole-cell patch-clamp and to extract total RNA and protein. Sheets of epithelium were used for short-circuit current recordings. KCNE1 and KCNE3 mRNA and protein abundance were significantly higher in male than female crypts. No expression of KCNE2 was found and no difference was observed in KCNQ1 expression between male and female (at oestrus) colonic crypts. Male crypts showed a 2.2-fold higher level of association of KCNQ1 and KCNE3 compared to female cells. In female colonic crypts, KCNQ1 and KCNE3 protein expression fluctuated throughout the oestrous cycle and 17beta-oestradiol (E2 10 nM) produced a rapid (<15 min) dissociation of KCNQ1 and KCNE3 in female crypts only. Whole-cell K(+) currents showed a linear current-voltage relationship in male crypts, while K(+) currents in colonic crypts isolated from females displayed voltage-dependent outward rectification. Currents in isolated male crypts and epithelial sheets were 10-fold more sensitive to specific KCNQ1 inhibitors, such as chromanol 293B and HMR-1556, than in female. The effect of E2 on K(+) currents mediated by KCNQ1 with or without different beta-subunits was assayed from current-voltage relations elicited in CHO cells transfected with KCNQ1 and KCNE3 or KCNE1 cDNA. E2 (100 nM) reduced the currents mediated by the KCNQ1:KCNE3 potassium channel and had no effect on currents via KCNQ1:KCNE1 or KCNQ1 alone. Currents mediated by the complex formed by KCNQ1 and the mutant KCNE3-S82A beta-subunit (mutation of the site for PKCdelta-promoted phosphorylation and modulation of the activity of KCNE3) showed rapid run-down and insensitivity to E2. Together, these data suggest that oestrogen regulates the expression of the KCNE1 and KCNE3 and with it the gating and pharmacological properties of the K(+) conductance required for Cl(-) secretion. The decreased association of the KCNQ1:KCNE3 channel complex promoted by oestrogen exposure underlies the molecular mechanism for the sexual dimorphism and oestrous cycle dependence of the anti-secretory actions of oestrogen in the intestine.en_GB
dc.language.isoengen_GB
dc.titleSexual dimorphism and oestrogen regulation of KCNE3 expression modulates the functional properties of KCNQ1 K channels.en_GB
dc.contributor.departmentDepartment of Molecular Medicine, Education and Research Centre, Royal College of, Surgeons in Ireland, Beaumont Hospital, Dublin, Republic of Ireland.en_GB
dc.identifier.journalThe Journal of physiologyen_GB
dc.description.provinceLeinster-

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