title: Orai1 forms a signal complex with BKCa channel in mesenteric artery smooth muscle cells.
abstract: Orai1, a specific nonvoltage-gated Ca(2+) channel, has been found to be one of key molecules involved in store-operated Ca(2+) entry (SOCE). Orai1 may associate with other proteins to form a signaling complex, which is essential for regulating a variety of physiological functions. In this study, we studied the possible interaction between Orai1 and large conductance Ca(2+)-activated potassium channel (BKC a). Using RNA interference technique, we demonstrated that the SOCE and its associated membrane hyperpolarization were markedly suppressed after knockdown of Orai1 with a specific Orai1 siRNA in rat mesenteric artery smooth muscle. Moreover, isometric tension measurements showed that agonist-induced vasocontraction was increased after Orai1 was knocked down or the tissue was incubated with BKC a blocker iberiotoxin. Coimmunoprecipitation data revealed that BKC a and Orai1 could reciprocally pull down each other. In situ proximity ligation assay further demonstrated that Orai1 and BKC a are in close proximity. Taken together, these results indicate that Orai1 physically associates with BKC a to form a signaling complex in the rat mesenteric artery smooth muscle. Ca(2+) influx via Orai1 stimulates BKC a, leading to membrane hyperpolarization. This hyperpolarizing effect of Orai1-BKC a coupling could contribute to reduce agonist-induced membrane depolarization, therefore preventing excessive contraction of the rat mesenteric artery smooth muscle in response to contractile agonists.
authors.affiliation: Department of Physiology, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Meihua
authors.initials: M
authors.lastname: Chen
authors.affiliation: Department of Physiology, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Pediatrics, The people's hospital of Bozhou, Bozhou, Anhui, China.
authors.forename: Feifei
authors.initials: F
authors.lastname: Jiang
authors.affiliation: Department of Physiology, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Fu
authors.affiliation: Department of Gastroenterology and Hepatology, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Xianming
authors.initials: X
authors.lastname: Xia
authors.affiliation: Department of Physiology, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.affiliation: Department of Sports and Health, Guangdong Provincial Key Laboratory of Sports and Health Promotion, Guangzhou Sport University, Guangzhou, Guangdong, China.
authors.forename: Min
authors.initials: M
authors.lastname: Hu
authors.affiliation: Department of Sports and Health, Guangdong Provincial Key Laboratory of Sports and Health Promotion, Guangzhou Sport University, Guangzhou, Guangdong, China shenbing@ahmu.edu.cn junhaohuang2006@hotmail.com.
authors.forename: Junhao
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Physiology, Anhui Medical University, Hefei, Anhui, China Central Laboratory of Molecular and Cellular Biology of School of Basic Medicine, Anhui Medical University, Hefei, Anhui, China shenbing@ahmu.edu.cn junhaohuang2006@hotmail.com.
authors.forename: Bing
authors.initials: B
authors.lastname: Shen
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D000071740:ORAI1 Protein; D009924:Organ Culture Techniques; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology
chemical_list: D015220:Calcium Channels; C494842:Kcnma1 protein, rat; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D000071740:ORAI1 Protein; C532493:Orai1 protein, rat; D010656:Phenylephrine
keywords: BKC
  a; Orai1; mesenteric artery; store‐operated Ca2+ entry; vascular smooth muscle cells