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Functional Analysis of a Mouse Brain Elk-Type K+Channel
- Source :
- The Journal of Neuroscience. 19:2906-2918
- Publication Year :
- 1999
- Publisher :
- Society for Neuroscience, 1999.
-
Abstract
- Members of the Ether à go-go (Eag) K+channel subfamilies Eag, Erg, and Elk are widely expressed in the nervous system, but their neural functionsin vivoremain largely unknown. The biophysical properties of channels from the Eag and Erg subfamilies have been described, and based on their characteristic features and expression patterns, Erg channels have been associated with native currents in the heart. Little is known about the properties of channels from the Elk subfamily. We have identified a mouse gene,Melk2, that encodes a predicted polypeptide with 48% amino acid identity toDrosophilaElk but only 40 and 36% identity with mouse Erg (Merg) and Eag (Meag), respectively.Melk2RNA appears to be expressed at high levels only in brain tissue. Functional expression ofMelk2inXenopusoocytes reveals large, transient peaks of current at the onset of depolarization. Like Meag currents, Melk2 currents activate relatively quickly, but they lack the nonsuperimposable Cole–Moore shift characteristic of the Eag subfamily. Melk2 currents are insensitive to E-4031, a class III antiarrhythmic compound that blocks the Human Ether-à-go-go-Related Gene (HERG) channel and its counterpart in native tissues, IKr. Melk2 channels exhibit inward rectification because of a fast C-type inactivation mechanism, but the slower rate of inactivation and the faster rate of activation results in less inward rectification than that observed in HERG channels. This characterization of Melk currents should aid in identification of native counterparts to the Elk subfamily of channels in the nervous system.
- Subjects :
- Nervous system
Potassium Channels
Subfamily
Xenopus
Molecular Sequence Data
hERG
Action Potentials
Nerve Tissue Proteins
Protein Serine-Threonine Kinases
Bioinformatics
Article
Mice
medicine
Animals
Humans
Amino Acid Sequence
Gene
Sequence Homology, Amino Acid
biology
General Neuroscience
Brain
RNA
Depolarization
biology.organism_classification
Ether-A-Go-Go Potassium Channels
Cell biology
Kinetics
medicine.anatomical_structure
Multigene Family
Oocytes
biology.protein
Erg
Subjects
Details
- ISSN :
- 15292401 and 02706474
- Volume :
- 19
- Database :
- OpenAIRE
- Journal :
- The Journal of Neuroscience
- Accession number :
- edsair.doi.dedup.....90001cee6c33fc037e1ddefaab1b73b2