Centro Interdisciplinario de Neurociencia de Valparaiso, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile.
FEBS Lett. 2012 Jul 30;586(16):2287-93. doi: 10.1016/j.febslet.2012.05.066. Epub 2012 Jun 16.
The BK channel is one of the most broadly expressed ion channels in mammals. In many tissues, the BK channel pore-forming α-subunit is associated to an auxiliary β-subunit that modulates the voltage- and Ca(2+)-dependent activation of the channel. Structural components present in β-subunits that are important for the physical association with the α-subunit are yet unknown. Here, we show through co-immunoprecipitation that the intracellular C-terminus, the second transmembrane domain (TM2) and the extracellular loop of the β2-subunit are dispensable for association with the α-subunit pointing transmembrane domain 1 (TM1) as responsible for the interaction. Indeed, the TOXCAT assay for transmembrane protein-protein interactions demonstrated for the first time that TM1 of the β2-subunit physically binds to the transmembrane S1 domain of the α-subunit.
BK 通道是哺乳动物中表达最广泛的离子通道之一。在许多组织中，BK 通道的孔形成α亚基与调节通道的电压和 Ca(2+)依赖性激活的辅助β亚基相关。β亚基中存在的对于与α亚基物理结合很重要的结构成分尚不清楚。在这里，我们通过共免疫沉淀表明，β2 亚基的细胞内 C 末端、第二跨膜域 (TM2) 和细胞外环对于与 α 亚基的结合是可有可无的，指向跨膜域 1 (TM1) 负责相互作用。事实上，用于跨膜蛋白-蛋白相互作用的 TOXCAT 测定法首次表明，β2 亚基的 TM1 与 α 亚基的跨膜 S1 结构域物理结合。
