ArticleThe Journal of general physiology1990
GTP-dependent regulation of myometrial KCa channels incorporated into lipid bilayers.
Article in The Journal of general physiology, 1990. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers.
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Who cites it
17 citing papers in PubMed, 86 citations in OpenAlex.
- A Lipid Bilayer Formed on a Hydrogel Bead for Single Ion Channel Recordings.Micromachines · 2020Article
- The angiotensin II type 1 receptor (AT1R) closely interacts with large conductance voltage- and Ca2+-activated K+ (BK) channels and inhibits their activity independent of G-protein activation.The Journal of biological chemistry · 2014Article
- MaxiK channel and cell signalling.Pflugers Archiv : European journal of physiology · 2014Review
- Functional insights into modulation of BKCa channel activity to alter myometrial contractility.Frontiers in physiology · 2014Review
- The effect of trichostatin-A and tumor necrosis factor on expression of splice variants of the MaxiK and L-type channels in human myometrium.Frontiers in physiology · 2014Article
- Thromboxane A2 receptor and MaxiK-channel intimate interaction supports channel trans-inhibition independent of G-protein activation.Proceedings of the National Academy of Sciences of the United States of America · 2010Article
- MaxiK channel partners: physiological impact.The Journal of physiology · 2006Review
- Characterization of a functionally expressed stretch-activated BKca channel cloned from chick ventricular myocytes.The Journal of membrane biology · 2003Article
- Distinct regions of the slo subunit determine differential BKCa channel responses to ethanol.Alcoholism, clinical and experimental research · 2003Article
- Rat supraoptic magnocellular neurones show distinct large conductance, Ca2+-activated K+ channel subtypes in cell bodies versus nerve endings.The Journal of physiology · 1999Article
- dSLo interacting protein 1, a novel protein that interacts with large-conductance calcium-activated potassium channels.The Journal of neuroscience : the official journal of the Society for Neuroscience · 1998Article
- Characterization of the G protein coupling of SRIF and beta-adrenergic receptors to the maxi KCa channel in insulin-secreting cells.The Journal of membrane biology · 1995Article
- Reconstitution of expressed KCa channels from Xenopus oocytes to lipid bilayers.Biophysical journal · 1994Article
- Stimulatory and inhibitory regulation of calcium-activated potassium channels by guanine nucleotide-binding proteins.Proceedings of the National Academy of Sciences of the United States of America · 1992Article
- G-protein-mediated regulation of a Ca(2+)-dependent K+ channel in cultured vascular endothelial cells.Pflugers Archiv : European journal of physiology · 1992Article
- Calcium-activated K+ channels: metabolic regulation.Journal of bioenergetics and biomembranes · 1991Review
- Calcium-activated potassium channels: regulation by calcium.Journal of bioenergetics and biomembranes · 1991Review
Corrections and comments
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Authors and funding
3 authors at 1 institution in 1 country.
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Abstract
The regulation of calcium-activated K (KCa) channels by a G protein-mediated mechanism was studied. KCa channels were reconstituted in planar lipid bilayers by fusion of membrane vesicles from rat or pig myometrium. The regulatory process was studied by exploring the actions of GTP and GTP gamma S on single channel activity. KCa channels had a conductance of 260 +/- 6 pS (n = 25, +/- SE, 250/50 mM KCl gradient) and were voltage dependent. The open probability (Po) vs. voltage relationships were well fit by a Boltzmann distribution. The slope factor (11 mV) was insensitive to internal Ca2+. The half activation potential (V1/2) was shifted -70 mV by raising internal Ca2+ from pCa 6.2 to pCa 4. Addition of GTP or GTP gamma S activated channel activity only in the presence of Mg2+, a characteristic typical of G protein-mediated mechanisms. The Po increased from 0.18 +/- 0.08 to 0.49 +/- 0.07 (n = 7, 0 mV, pCa 6 to 6.8). The channel was also activated (Po increased from 0.03 to 0.37) in the presence of AMP-PNP, a nonphosphorylating ATP analogue, suggesting a direct G protein gating of KCa channels. Upon nucleotide activation, mean open time increased by a factor of 2.7 +/- 0.7 and mean closed time decreased by 0.2 +/- 0.07 of their initial values (n = 6). Norepinephrine (NE) or isoproterenol potentiated the GTP-mediated activation of KCa channels (Po increased from 0.17 +/- 0.06 to 0.35 +/- 0.07, n = 10). These results suggest that myometrium possesses beta-adrenergic receptors coupled to a GTP-dependent protein that can directly gate KCa channels. Furthermore, KCa channels, beta-adrenergic receptors, and G proteins can be reconstituted in lipid bilayers as a stable, functionally coupled, molecular complex.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.