LRRC26 is a functional BK channel auxiliary γ subunit in arterial smooth muscle cells.
Circ Res
; 115(4): 423-31, 2014 Aug 01.
Article
em En
| MEDLINE
| ID: mdl-24906643
ABSTRACT
RATIONALE Smooth muscle cell (myocyte) large-conductance calcium (Ca)(2+)-activated potassium (BK) channels are functionally significant modulators of arterial contractility. Arterial myocytes express both pore-forming BKα and auxiliary ß1 subunits, which increase channel Ca(2+) sensitivity. Recently, several leucine-rich repeat containing (LRRC) proteins have been identified as auxiliary γ subunits that elevate the voltage sensitivity of recombinant and prostate adenocarcinoma BK channels. LRRC expression and physiological functions in native cell types are unclear. OBJECTIVE:
Investigate the expression and physiological functions of leucine-rich repeat containing protein 26 (LRRC26) in arterial myocytes. METHODS ANDRESULTS:
Reverse transcription polymerase chain reaction and Western blotting detected LRRC26 mRNA and protein in cerebral artery myocytes. Biotinylation, immunofluorescence resonance energy transfer microscopy, and coimmunoprecipitation indicated that LRRC26 was located in close spatial proximity to, and associated with, plasma membrane BKα subunits. LRRC26 knockdown (RNAi) reduced total and surface LRRC26, but did not alter BKα or ß1, proteins in arteries. LRRC26 knockdown did not alter Ca(2+) sparks but reduced BK channel voltage sensitivity, which decreased channel apparent Ca(2+) sensitivity and transient BK current frequency and amplitude in myocytes. LRRC26 knockdown also increased myogenic tone over a range (40-100 mm Hg) of intravascular pressures, and reduced vasoconstriction to iberiotoxin and vasodilation to NS1619, BK channel inhibitors and activators, respectively. In contrast, LRRC26 knockdown did not alter depolarization (60 mmol/L K(+))-induced vasoconstriction.CONCLUSIONS:
LRRC26 is expressed, associates with BKα subunits, and elevates channel voltage- and apparent Ca(2+) sensitivity in arterial myocytes to induce vasodilation. This study indicates that arterial myocytes express a functional BK channel γ subunit.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Miócitos de Músculo Liso
/
Canais de Potássio Ativados por Cálcio de Condutância Alta
/
Músculo Liso Vascular
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Proteínas de Neoplasias
Limite:
Animals
Idioma:
En
Revista:
Circ Res
Ano de publicação:
2014
Tipo de documento:
Article