scholarly journals Proximal C-terminal domain of sulphonylurea receptor 2A interacts with pore-forming Kir6 subunits in KATP channels

2004 ◽  
Vol 379 (1) ◽  
pp. 173-181 ◽  
Author(s):  
Richard D. RAINBOW ◽  
Marian JAMES ◽  
Diane HUDMAN ◽  
Mohammed AL JOHI ◽  
Harprit SINGH ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Katp Channel ◽  
Direct Interaction ◽  
Katp Channels ◽  
Full Length ◽  
Hek 293 ◽  
Sulphonylurea Receptor ◽  
Hek 293 Cells ◽  
Terminal Domain ◽  
293 Cells

Functional KATP (ATP-sensitive potassium) channels are hetero-octamers of four Kir6 (inwardly rectifying potassium) channel subunits and four SUR (sulphonylurea receptor) subunits. Possible interactions between the C-terminal domain of SUR2A and Kir6.2 were investigated by co-immunoprecipitation of rat SUR2A C-terminal fragments with full-length Kir6.2 and by analysis of cloned KATP channel function and distribution in HEK-293 cells (human embryonic kidney 293 cells) in the presence of competing rSUR2A fragments. Three maltose-binding protein–SUR2A fusions, rSUR2A-CTA (rSUR2A residues 1254–1545), rSUR2A-CTB (residues 1254–1403) and rSUR2A-CTC (residues 1294–1403), were co-immunoprecipitated with full-length Kir6.2 using a polyclonal anti-Kir6.2 antiserum. A fourth C-terminal domain fragment, rSUR2A-CTD (residues 1358–1545) did not co-immunoprecipitate with Kir6.2 under the same conditions, indicating a direct interaction between Kir6.2 and a 65-amino-acid section of the cytoplasmic C-terminal region of rSUR2A between residues 1294 and 1358. ATP- and glibenclamide-sensitive K+ currents were decreased in HEK-293 cells expressing full-length Kir6 and SUR2 subunits that were transiently transfected with fragments rSUR2A-CTA, rSUR2A-CTC and rSUR2A-CTE (residues 1294–1359) compared with fragment rSUR2A-CTD or mock-transfected cells, suggesting either channel inhibition or a reduction in the number of functional KATP channels at the cell surface. Anti-KATP channel subunit-associated fluorescence in the cell membrane was substantially lower and intracellular fluorescence increased in rSUR2A-CTE expressing cells; thus, SUR2A fragments containing residues 1294–1358 reduce current by decreasing the number of channel subunits in the cell membrane. These results identify a site in the C-terminal domain of rSUR2A, between residues 1294 and 1358, whose direct interaction with full-length Kir6.2 is crucial for the assembly of functional KATP channels.

scholarly journals Photobiomodulation on KATP Channels of Kir6.2-Transfected HEK-293 Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Fu-qing Zhong ◽  
Yang Li ◽  
Xian-qiang Mi
Keyword(s):  
Laser Irradiation ◽  
Katp Channel ◽  
Cell Metabolism ◽  
Katp Channels ◽  
Open Probability ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
Low Intensity ◽  
293 Cells ◽  
Excised Patches

Background and Objective. ATP-sensitive potassium (KATP) channel couples cell metabolism to excitability. To explore role of KATP channels in cellular photobiomodulation, we designed experiment to study effect of low intensity 808 nm laser irradiation on the activity of membrane KATP channel.Study Design/Materials and Methods. Plasmids encoding Kir6.2 was constructed and heterologously expressed in cultured mammalian HEK-293 cells. The patch-clamp and data acquisition systems were used to record KATP channel current before and after irradiation. A laser beam of Ga-As 808 nm at 5 mW/cm2was used in experiments. A one-way ANOVA test followed by apost hocStudent-Newman-Keuls test was used to assess the statistical differences between data groups.Results. Obvious openings of KATP channels of Kir6.2-transfected HEK-293 cells and excised patches were recorded during and after low intensity 808 nm laser irradiation. Compared with the channels that did not undergo irradiation, open probability, current amplitude, and dwell time of KATP channels after irradiation improved.Conclusions. Low intensity 808 nm laser irradiation may activate membrane KATP channels of Kir6.2-transfected HEK-293 cells and in excised patches.

scholarly journals Pharmacology of human sulphonylurea receptor SUR1 and inward rectifier K+ channel Kir6.2 combination expressed in HEK-293 cells

2000 ◽  
Vol 129 (7) ◽  
pp. 1323-1332 ◽  
Author(s):  
Murali Gopalakrishnan ◽  
Eduardo J Molinari ◽  
Char-Chang Shieh ◽  
Lisa M Monteggia ◽  
Jean-Marc Roch ◽  
...  
Keyword(s):  
Inward Rectifier ◽  
K Channel ◽  
Hek 293 ◽  
Sulphonylurea Receptor ◽  
Hek 293 Cells ◽  
293 Cells

Unique modulation of L-type Ca2+ channels by short auxiliary β1d subunit present in cardiac muscle

2005 ◽  
Vol 288 (5) ◽  
pp. H2363-H2374 ◽  
Author(s):  
Risa M. Cohen ◽  
Jason D. Foell ◽  
Ravi C. Balijepalli ◽  
Vaibhavi Shah ◽  
Johannes W. Hell ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Single Channel ◽  
Surface Membrane ◽  
Full Length ◽  
Open Probability ◽  
Western Blots ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
Amino Terminal ◽  
293 Cells

Recent studies have identified a growing diversity of splice variants of auxiliary Ca2+ channel Cavβ subunits. The Cavβ1d isoform encodes a putative protein composed of the amino-terminal half of the full-length Cavβ1 isoform and thus lacks the known high-affinity binding site that recognizes the Ca2+ channel α1-subunit, the α-binding pocket. The present study investigated whether the Cavβ1d subunit is expressed at the protein level in heart, and whether it exhibits any of the functional properties typical of full-length Cavβ subunits. On Western blots, an antibody directed against the unique carboxyl terminus of Cavβ1d identified a protein of the predicted molecular mass of 23 kDa from canine and human hearts. Immunocytochemistry and surface-membrane biotinylation experiments in transfected HEK-293 cells revealed that the full-length Cavβ1b subunit promoted membrane trafficking of the pore-forming α1C (Cav1.2)-subunit to the surface membrane, whereas the Cavβ1d subunit did not. Whole cell patch-clamp analysis of transfected HEK-293 cells demonstrated no effect of coexpression of the Cavβ1d with the α1C-subunit compared with the 15-fold larger currents and leftward shift in voltage-dependent activation induced by full-length Cavβ1b coexpression. In contrast, cell-attached patch single-channel studies demonstrated that coexpression of either Cavβ1b or Cavβ1d significantly increased mean open probability four- to fivefold relative to the α1C-channels alone, but only Cavβ1b coexpression increased the number of channels observed per patch. In conclusion, the Cavβ1d isoform is expressed in heart and can modulate the gating of L-type Ca2+ channels, but it does not promote membrane trafficking of the channel complex.

scholarly journals Beyond Ca2+ signalling: the role of TRPV3 in the transport of NH4+

2021 ◽  
Author(s):  
Hendrik Liebe ◽  
Franziska Liebe ◽  
Gerhard Sponder ◽  
Sarah Hedtrich ◽  
Friederike Stumpff
Keyword(s):  
Cell Membrane ◽  
Human Skin ◽  
Single Channel ◽  
Ruthenium Red ◽  
Channel Measurements ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
Intestinal Epithelia ◽  
Skin Equivalents ◽  
293 Cells

AbstractMutations of TRPV3 lead to severe dermal hyperkeratosis in Olmsted syndrome, but whether the mutants are trafficked to the cell membrane or not is controversial. Even less is known about TRPV3 function in intestinal epithelia, although research on ruminants and pigs suggests an involvement in the uptake of NH4+. It was the purpose of this study to measure the permeability of the human homologue (hTRPV3) to NH4+, to localize hTRPV3 in human skin equivalents, and to investigate trafficking of the Olmsted mutant G573S. Immunoblotting and immunostaining verified the successful expression of hTRPV3 in HEK-293 cells and Xenopus oocytes with trafficking to the cell membrane. Human skin equivalents showed distinct staining of the apical membrane of the top layer of keratinocytes with cytosolic staining in the middle layers. Experiments with pH-sensitive microelectrodes on Xenopus oocytes demonstrated that acidification by NH4+ was significantly greater when hTRPV3 was expressed. Single-channel measurements showed larger conductances in overexpressing Xenopus oocytes than in controls. In whole-cell experiments on HEK-293 cells, both enantiomers of menthol stimulated influx of NH4+ in hTRPV3 expressing cells, but not in controls. Expression of the mutant G573S greatly reduced cell viability with partial rescue via ruthenium red. Immunofluorescence confirmed cytosolic expression, with membrane staining observed in a very small number of cells. We suggest that expression of TRPV3 by epithelia may have implications not just for Ca2+ signalling, but also for nitrogen metabolism. Models suggesting how influx of NH4+ via TRPV3 might stimulate skin cornification or intestinal NH4+ transport are discussed.

scholarly journals Characteristics and requirements of basal autophagy in HEK 293 cells

Autophagy ◽  
2013 ◽  
Vol 9 (9) ◽  
pp. 1407-1417 ◽  
Author(s):  
Patience Musiwaro ◽  
Matthew Smith ◽  
Maria Manifava ◽  
Simon A. Walker ◽  
Nicholas T. Ktistakis
Keyword(s):  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells

Halothane Inhibition of Recombinant Cardiac L-type Ca2+ Channels Expressed in HEK-293 Cells

2005 ◽  
Vol 103 (6) ◽  
pp. 1156-1166 ◽  
Author(s):  
Kevin J. Gingrich ◽  
Son Tran ◽  
Igor M. Nikonorov ◽  
Thomas J. Blanck
Keyword(s):  
Charge Transfer ◽  
Calcium Channels ◽  
Dependent Manner ◽  
Current Time ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Dependent Inactivation ◽  
Voltage Dependent

Background Volatile anesthetics depress cardiac contractility, which involves inhibition of cardiac L-type calcium channels. To explore the role of voltage-dependent inactivation, the authors analyzed halothane effects on recombinant cardiac L-type calcium channels (alpha1Cbeta2a and alpha1Cbeta2aalpha2/delta1), which differ by the alpha2/delta1 subunit and consequently voltage-dependent inactivation. Methods HEK-293 cells were transiently cotransfected with complementary DNAs encoding alpha1C tagged with green fluorescent protein and beta2a, with and without alpha2/delta1. Halothane effects on macroscopic barium currents were recorded using patch clamp methodology from cells expressing alpha1Cbeta2a and alpha1Cbeta2aalpha2/delta1 as identified by fluorescence microscopy. Results Halothane inhibited peak current (I(peak)) and enhanced apparent inactivation (reported by end pulse current amplitude of 300-ms depolarizations [I300]) in a concentration-dependent manner in both channel types. alpha2/delta1 coexpression shifted relations leftward as reported by the 50% inhibitory concentration of I(peak) and I300/I(peak)for alpha1Cbeta2a (1.8 and 14.5 mm, respectively) and alpha1Cbeta2aalpha2/delta1 (0.74 and 1.36 mm, respectively). Halothane reduced transmembrane charge transfer primarily through I(peak) depression and not by enhancement of macroscopic inactivation for both channels. Conclusions The results indicate that phenotypic features arising from alpha2/delta1 coexpression play a key role in halothane inhibition of cardiac L-type calcium channels. These features included marked effects on I(peak) inhibition, which is the principal determinant of charge transfer reductions. I(peak) depression arises primarily from transitions to nonactivatable states at resting membrane potentials. The findings point to the importance of halothane interactions with states present at resting membrane potential and discount the role of inactivation apparent in current time courses in determining transmembrane charge transfer.

Micropatterned surfaces of PDMS as growth templates for HEK 293 cells

2007 ◽  
Vol 9 (4) ◽  
pp. 475-485 ◽  
Author(s):  
R. M. Johann ◽  
Ch. Baiotto ◽  
Ph. Renaud
Keyword(s):  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells

Calcium Induces Expression of Cytoplasmic Gelsolin in SH-SY5Y and HEK-293 Cells

2010 ◽  
Vol 35 (7) ◽  
pp. 1075-1082 ◽  
Author(s):  
Lina Ji ◽  
Abha Chauhan ◽  
Ved Chauhan
Keyword(s):  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Cytoplasmic Gelsolin
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