Cloning and characterization of zebrafish K2P13.1 (THIK-1) two-pore-domain K+ channels. (January 2019)

• Record Type: Journal Article
• Authors: Staudacher, Ingo; Seehausen, Sebastian; Gierten, Jakob; Illg, Claudius; Schweizer, Patrick A.; Katus, Hugo A.; Thomas, Dierk
• Is Part Of: Journal of molecular and cellular cardiology. Volume 126(2019)
• Page Start: 96
• Page End: 104
• Publication Date: 2019-01
• Subjects: Antiarrhythmic therapy -- Cardiac arrhythmia -- K2P channel, K2P13.1 (THIK-1) -- Zebrafish; h human -- K2P two-pore-domain K+ channel -- P pore -- THIK-1 tandem pore domain halothane inhibited K+ channel 1 -- TM transmembrane -- z zebrafish; Cardiology -- Periodicals; Heart Diseases -- Periodicals; Molecular Biology -- Periodicals; Cardiologie -- Périodiques; Cardiology; Electronic journals; Periodicals; 616.12
• DOI: 10.1016/j.yjmcc.2018.11.013
• Languages: English
• ISSNs: 0022-2828

Abstract

Abstract: Two-pore-domain potassium (K2P ) channels conduct background potassium currents in the heart and other tissues. K2P currents are involved in the repolarization of action potentials and stabilize the resting membrane potential. Human K2P 13.1 (THIK-1) channels are expressed in the heart and have recently been implicated in atrial fibrillation. The in vivo significance of K2P 13.1 currents in cardiac electrophysiology is not known. We hypothesized that Danio rerio (zebrafish) may serve as model to elucidate the functional role of cardiac K2P 13.1 channels. This work was designed to characterize zebrafish orthologs of K2P 13.1. Two zkcnk13 coding sequences were identified by DNA database searches and amplified from zebrafish cDNA. Human and zebrafish K2P 13.1 proteins exhibit 70% (K2P 13.1a) and 66% (K2P 13.1b) identity. Kcnk13 expression in zebrafish was studied using polymerase chain reaction. Zebrafish kcnk13a and z kcnk13b mRNAs were detected in brain and heart. Human and zebrafish K2P 13.1 currents were analyzed in the Xenopus oocyte expression system by voltage clamp electrophysiology. Zebrafish K2P 13.1a polypeptides were non-functional, while zK2P 13.1b channels exhibited K + selective, outwardly rectifying currents. Zebrafish and human K2P 13.1 currents were similarly activated by arachidonic acid and reduced by barium, mexiletine, lidocaine, and inhibition of phospholipase C. In conclusion, zebrafish K2P 13.1b channels and their human orthologs exhibit structural and regulatory similarities. Zebrafish may be used as in vivo model for the assessment of physiology and therapeutic significance of K2P 13.1. Highlights: Two kcnk 13 (THIK-1) orthologs were cloned from zebrafish cDNA. K2P 13.1a subunits do not give rise to functional ion channels. Human K2P 13.1 and zebrafish K2P 13.1b show similar biophysical characteristics and regulation. hK2P 13.1 and zK2P 13.1s are activated by arachidonic acid and blocked by mexiletine and lidocaine. Zebrafish could be employed as model system for physiological K2P 13.1 in vivo studies.