Gierten Jakob, Hassel David, Schweizer Patrick A, Becker Rüdiger, Katus Hugo A, Thomas Dierk
Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany.
Biochim Biophys Acta. 2012 Jan;1818(1):33-41. doi: 10.1016/j.bbamem.2011.09.015. Epub 2011 Sep 22.
Two-pore-domain potassium (K(2P)) channels mediate K(+) background currents that stabilize the resting membrane potential and contribute to repolarization of action potentials in excitable cells. The functional significance of K(2P) currents in cardiac electrophysiology remains poorly understood. Danio rerio (zebrafish) may be utilized to elucidate the role of cardiac K(2P) channels in vivo. The aim of this work was to identify and functionally characterize a zebrafish otholog of the human K(2P)10.1 channel. K(2P)10.1 orthologs in the D. rerio genome were identified by database analysis, and the full zK(2P)10.1 coding sequence was amplified from zebrafish cDNA. Human and zebrafish K(2P)10.1 proteins share 61% identity. High degrees of conservation were observed in protein domains relevant for structural integrity and regulation. K(2P)10.1 channels were heterologously expressed in Xenopus oocytes, and currents were recorded using two-electrode voltage clamp electrophysiology. Human and zebrafish channels mediated K(+) selective background currents leading to membrane hyperpolarization. Arachidonic acid, an activator of hK(2P)10.1, induced robust activation of zK(2P)10.1. Activity of both channels was reduced by protein kinase C. Similar to its human counterpart, zK(2P)10.1 was inhibited by the antiarrhythmic drug amiodarone. In summary, zebrafish harbor K(2P)10.1 two-pore-domain K(+) channels that exhibit structural and functional properties largely similar to human K(2P)10.1. We conclude that the zebrafish represents a valid model to study K(2P)10.1 function in vivo.
双孔域钾离子（K(2P)）通道介导钾离子背景电流，该电流可稳定静息膜电位，并有助于可兴奋细胞动作电位的复极化。K(2P)电流在心脏电生理学中的功能意义仍知之甚少。斑马鱼可用于阐明心脏K(2P)通道在体内的作用。这项工作的目的是鉴定并在功能上表征人类K(2P)10.1通道的斑马鱼同源物。通过数据库分析在斑马鱼基因组中鉴定出K(2P)10.1同源物，并从斑马鱼cDNA中扩增出完整的zK(2P)10.1编码序列。人类和斑马鱼的K(2P)10.1蛋白具有61%的同一性。在与结构完整性和调节相关的蛋白质结构域中观察到高度保守性。K(2P)10.1通道在非洲爪蟾卵母细胞中进行异源表达，并使用双电极电压钳电生理学记录电流。人类和斑马鱼通道介导钾离子选择性背景电流，导致膜超极化。花生四烯酸是hK(2P)10.1的激活剂，可强烈激活zK(2P)10.1。两种通道的活性均被蛋白激酶C降低。与人类对应物相似，zK(2P)10.1被抗心律失常药物胺碘酮抑制。总之，斑马鱼含有K(2P)10.1双孔域钾离子通道，其结构和功能特性与人类K(2P)10.1基本相似。我们得出结论，斑马鱼是研究K(2P)10.1在体内功能的有效模型。
