LRRC26 is a functional BK channel auxiliary γ subunit in arterial smooth muscle cells.
LRRC26 is a functional BK channel auxiliary γ subunit in arterial smooth muscle cells.
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LRRC26 是动脉平滑肌细胞中的功能性 BK 通道辅助 γ 亚基。
DOI：
10.1161/circresaha.115.303407
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发表时间：
2014-08-01
影响因子：
20.1
通讯作者：
Jaggar JH
中科院分区：
文献类型：
--
作者：
Evanson KW;Bannister JP;Leo MD;Jaggar JH
平滑肌细胞（肌细胞）大电导钙（Ca2+）活化钾（BK）通道是动脉收缩性的重要功能调节剂。动脉肌细胞表达形成孔隙的BKα和辅助β1亚基，增加通道Ca2+的敏感性。最近，一些富含亮氨酸的重复序列（LRRC）蛋白被鉴定为辅助γ亚基，可提高重组蛋白和前列腺腺癌BK通道的电压敏感性。LRRC在天然细胞类型中的表达和生理功能尚不清楚。探讨LRRC26在动脉肌细胞中的表达及生理功能。RT-PCR和Western blotting检测脑动脉肌细胞中LRRC26 mRNA和蛋白表达。生物素化、免疫荧光共振能量转移显微镜和共免疫沉淀表明，LRRC26位于质膜BKα亚基附近，并与之相关。LRRC26敲低（RNAi）减少了总LRRC26和表面LRRC26，但没有改变动脉中的BKα或β1蛋白。LRRC26的敲低没有改变Ca2+火花，但降低了BK通道电压敏感性，从而降低了肌细胞中Ca2+的表观敏感性和瞬态BK电流的频率和幅度。LRRC26的下调也增加了血管内压力范围（40 - 100 mmHg）内的肌原性张力，并分别减少了血管收缩到iberiotoxin和血管舒张到NS1619、BK通道抑制剂和激活剂。相比之下，LRRC26基因敲低不改变去极化（60 mmol/L K+）诱导的血管收缩。LRRC26表达，与BKα亚基相关，并提高动脉肌细胞通道电压和明显Ca2+敏感性，诱导血管舒张。这项研究表明，动脉肌细胞表达一个功能性的BK通道γ亚基。
Smooth muscle cell (myocyte) large-conductance calcium (Ca2+)-activated potassium (BK) channels are functionally significant modulators of arterial contractility. Arterial myocytes express both pore-forming BKα and auxiliary β1 subunits, which increase channel Ca2+-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. Investigate the expression and physiological functions of LRRC26 in arterial myocytes. RT-PCR and Western blotting detected LRRC26 mRNA and protein in cerebral artery myocytes. Biotinylation, immunofluorescence resonance energy transfer microscopy and co-immunoprecipitation 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 β1, proteins in arteries. LRRC26 knockdown did not alter Ca2+ sparks, but reduced BK channel voltage-sensitivity, which reduced channel apparent Ca2+-sensitivity and transient BK current frequency and amplitude in myocytes. LRRC26 knockdown also increased myogenic tone over a range (40 – 100 mmHg) 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. LRRC26 is expressed, associates with BKα subunits, and elevates channel voltage- and apparent Ca2+-sensitivity in arterial myocytes to induce vasodilation. This study indicates that arterial myocytes express a functional BK channel γ subunit.