title: Identification and functional characterization of zebrafish K(2P)10.1 (TREK2) two-pore-domain K(+) channels.
abstract: 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.
authors.affiliation: Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, D-69120 Heidelberg, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Gierten
authors.forename: David
authors.initials: D
authors.lastname: Hassel
authors.forename: Patrick A
authors.initials: PA
authors.lastname: Schweizer
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Becker
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Katus
authors.forename: Dierk
authors.initials: D
authors.lastname: Thomas
mesh_terms: D000638:Amiodarone / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D016718:Arachidonic Acid / Q000494:pharmacology; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000096:biosynthesis; D004594:Electrophysiology; D015870:Gene Expression; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D009865:Oocytes / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010802:Phylogeny; D010957:Plasmids; D011188:Potassium / Q000378:metabolism*; D024683:Potassium Channels, Tandem Pore Domain / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014982:Xenopus laevis; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000889:Anti-Arrhythmia Agents; D018076:DNA, Complementary; C503438:KCNK10 protein, human; D024683:Potassium Channels, Tandem Pore Domain; D029961:Zebrafish Proteins; C571578:kcnk10a protein, zebrafish; D016718:Arachidonic Acid; D011493:Protein Kinase C; D000638:Amiodarone; D011188:Potassium