TBAK-1 and TASK-1, two-pore K+ channel subunits: kinetic properties and expression in rat heart
- Authors
- Kim, Yangmi; Bang, Hyoweon; Kim, Donghee
- Issue Date
- Nov-1999
- Publisher
- AMER PHYSIOLOGICAL SOC
- Keywords
- two-pore potassium channel; atrial cell; pH
- Citation
- AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, v.277, no.5, pp H1669 - H1678
- Journal Title
- AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
- Volume
- 277
- Number
- 5
- Start Page
- H1669
- End Page
- H1678
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/25382
- DOI
- 10.1152/ajpheart.1999.277.5.h1669
- ISSN
- 0363-6135
1522-1539
- Abstract
- TEAK-I and TASK-1, two-pore K+ channel subunits: kinetic properties and expression in rat heart. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H1669-H1678, 1999. -A mammalian K+ channel subunit (TBAK-1/TASK-1) containing two pore domains and four transmembrane segments and whose mRNA is highly expressed in the heart has been cloned recently. TEAK-I and TASK-1 are identical except for the additional nine amino acids in the NH2 terminus of TEAK-I. We examined their kinetic properties, pH sensitivity, and regional cardiac mRNA expression and determined whether a native cardiac K+ channel with similar kinetic properties was present. When TBAK-1 or TASK-1 was transiently expressed in COS-7 cells, time- and voltage-independent whole cell currents were observed. Single-channel conductances of TEAK-I and TASK-1 were 14.6 +/- 1.0 and 13.8 +/- 2.8 pS, respectively, at -80 mV in 140 mM extracellular K+, and the mean open times were 0.8 +/- 0.1 and 0.6 +/- 0.1 ms, respectively. Both TBAK-1 and TASK-1 were highly sensitive to extracellular pH such that a decrease from 7.2 to 6.4 reduced their open probability (P-o) by 81 +/- 14% and 80 +/- 16%, whereas a decrease in intracellular pH from 7.2 to 6.4 reduced the P-o by 42 +/- 10% and 47 +/- 12%, respectively. TBAK-1/TASK-1 mRNA was expressed in all regions of the rat heart, with the highest level of expression in the right atrium. A 14-pS K+ channel with kinetic properties similar to those of TBAK-1/TASK-1 was identified in rat atrial and ventricular cells. These results indicate that TBAK-1/TASK-1 represents a functional native K+ channel in the rat heart.
- Files in This Item
- There are no files associated with this item.
- Appears in
Collections - College of Medicine > College of Medicine > 1. Journal Articles
![qrcode](https://api.qrserver.com/v1/create-qr-code/?size=55x55&data=https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/25382)
Items in ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.