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G protein modulation of K2P potassium channel TASK-2
- Source :
- Pflügers Archiv - European Journal of Physiology. 465:1715-1726
- Publication Year :
- 2013
- Publisher :
- Springer Science and Business Media LLC, 2013.
-
Abstract
- TASK-2 (K2P5.1) is a background K(+) channel opened by extra- or intracellular alkalinisation that plays a role in renal bicarbonate handling, central chemoreception and cell volume regulation. Here, we present results that suggest that TASK-2 is also modulated by Gβγ subunits of heterotrimeric G protein. TASK-2 was strongly inhibited when GTP-γ-S was used as a replacement for intracellular GTP. No inhibition was present using GDP-β-S instead. Purified Gβγ introduced intracellularly also inhibited TASK-2 independently of whether GTP or GDP-β-S was present. The effects of GTP-γ-S and Gβγ subunits were abolished by neutralisation of TASK-2 C terminus double lysine residues K257-K258 or K296-K297. Use of membrane yeast two hybrid (MYTH) experiments and immunoprecipitation assays using tagged proteins gave evidence for a physical interaction between Gβ1 and Gβ2 subunits and TASK-2, in agreement with expression of these subunits in proximal tubule cells. Co-immunoprecipitation was impeded by mutating C terminus K257-K258 (but not K296-K297) to alanines. Gating by extra- or intracellular pH was unaltered in GTP-γ-S-insensitive TASK-2-K257A-K258A mutant. Shrinking TASK-2-expressing cells in hypertonic solution decreased the current to 36 % of its initial value. The same manoeuvre had a significantly diminished effect on TASK-2-K257A-K258A- or TASK-2-K296-K297-expressing cells, or in cells containing intracellular GDP-β-S. Our data are compatible with the concept that TASK-2 channels are modulated by Gβγ subunits of heterotrimeric G protein. We propose that this modulation is a novel way in which TASK-2 can be tuned to its physiological functions.
- Subjects :
- GTP'
Physiology
G protein
Intracellular pH
Clinical Biochemistry
Biology
Guanosine Diphosphate
Mice
Potassium Channels, Tandem Pore Domain
GTP-Binding Protein gamma Subunits
Two-Hybrid System Techniques
Physiology (medical)
Heterotrimeric G protein
Animals
Humans
Amino Acid Sequence
GTP-Binding Protein beta Subunits
Thionucleotides
Heterotrimeric GTP-Binding Proteins
Potassium channel
Cell biology
G beta-gamma complex
HEK293 Cells
G12/G13 alpha subunits
Ion Channel Gating
Intracellular
Subjects
Details
- ISSN :
- 14322013 and 00316768
- Volume :
- 465
- Database :
- OpenAIRE
- Journal :
- Pflügers Archiv - European Journal of Physiology
- Accession number :
- edsair.doi.dedup.....9ddd8a55f0725f55f09697f5f54fcf6c