TASK1 (K(2P)3.1) K(+) channel inhibition by endothelin-1 is mediated through Rho kinase-dependent phosphorylation.
Br J Pharmacol
; 165(5): 1467-75, 2012 Mar.
Article
in En
| MEDLINE
| ID: mdl-21838752
ABSTRACT
BACKGROUND AND PURPOSE:
TASK1 (K(2P)3.1) two-pore-domain K(+) channels contribute substantially to the resting membrane potential in human pulmonary artery smooth muscle cells (hPASMC), modulating vascular tone and diameter. The endothelin-1 (ET-1) pathway mediates vasoconstriction and is an established target of pulmonary arterial hypertension (PAH) therapy. ET-1-mediated inhibition of TASK1 currents in hPASMC is implicated in the pathophysiology of PAH. This study was designed to elucidate molecular mechanisms underlying inhibition of TASK1 channels by ET-1. EXPERIMENTALAPPROACH:
Two-electrode voltage clamp and whole-cell patch clamp electrophysiology was used to record TASK1 currents from hPASMC and Xenopus oocytes. KEYRESULTS:
ET-1 inhibited TASK1-mediated I(KN) currents in hPASMC, an effect attenuated by Rho kinase inhibition with Y-27632. In Xenopus oocytes, TASK1 current reduction by ET-1 was mediated by endothelin receptors ET(A) (IC(50) = 0.08 nM) and ET(B) (IC(50) = 0.23 nM) via Rho kinase signalling. TASK1 channels contain two putative Rho kinase phosphorylation sites, Ser(336) and Ser(393) . Mutation of Ser(393) rendered TASK1 channels insensitive to ET(A) - or ET(B)-mediated current inhibition. In contrast, removal of Ser(336) selectively attenuated ET(A) -dependent TASK1 regulation without affecting the ET(B) pathway. CONCLUSIONS AND IMPLICATIONS ET-1 regulated vascular TASK1 currents through ET(A) and ET(B) receptors mediated by downstream activation of Rho kinase and direct channel phosphorylation. The Rho kinase pathway in PASMC may provide a more specific therapeutic target in pulmonary arterial hypertension treatment.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Endothelin-1
/
Potassium Channels, Tandem Pore Domain
/
Rho-Associated Kinases
/
Nerve Tissue Proteins
Limits:
Animals
/
Female
/
Humans
Language:
En
Journal:
Br J Pharmacol
Year:
2012
Document type:
Article