Coexpression of SUR2B and Kir 6.2 with Kir 6.1 dominant negatives at a 1 : 1 expression ratio and vice versa led to a potent suppression of current .
Each of the SUR2 splice variants transiently expressed with the inward rectifier Kir 6.2 formed functional K ( ATP ) channels in HEK 293 cells as assessed either by changes in DiBAC(4) (3) fluorescence responses or glyburide-sensitive whole cell currents .
RT-PCR demonstrated the presence of Kir 6.2 and SUR2B transcripts in colonic smooth muscle cells ; transcripts for Kir 6.1 , SUR1 , and SUR2A were not detected .
To determine the presence of Kir and SURs subunits , RT-PCR was performed using Kir6.1 , Kir6.2 , SUR1 , SUR2A , and SUR2B gene-specific primers .
Reverse transcriptase-polymerase chain reaction identified K ( ATP ) channel component gene expression including regulatory sulfonylurea receptors ( SUR ) SUR1 and SUR2B but not SUR2A and pore-forming subunits ( Kir ) Kir6.1 and Kir6.2 .
We have used the baculovirus transduction system , BacMam , to demonstrate transient expression of multi-subunit KATP channels in CHO-K1 and HEK-293 EBNA cells using sulfonylurea receptor 1 ( SUR ) , SUR2A , SUR2B , and KIR 6.2 genes. [3H] -glyburide binding , patch clamp , and DiBAC4(3) measurements of membrane potential changes were used to monitor channel expression .
Expression of RAMP1 , calcitonin receptor-like receptor , Kir 6.1 and SUR2B was not modified by liver cirrhosis .
Reverse transcription-polymerase chain reaction ( RT-PCR ) and Western blot were applied to evaluate expression of sulfonylurea receptor 2A ( SUR2A ) and Kir 6.2 .
Polyclonal antibodies raised against certain fragments of known sulphonylurea receptor subunits , SUR1 and SUR2 , and against different epitopes of K+ inward rectifier subunits Kir 6.1 and Kir 6.2 of the ATP-sensitive K+ channel of the plasma membrane ( cellKATP ) , were employed to detect similar subunits in brain mitochondria .
We found that K ( ATP ) channel components Kir 6.1 and 6.2 and SUR2 were expressed in oligodendrocytes .
Here , we demonstrated for the first time that Kir 6.1 , Kir 6.2 and SUR2 subunits of K ( ATP ) channels are functionally expressed in HaCaT cells and both non-selective K ( ATP ) channel opener pinacidil and mitoK ( ATP ) ( mitochondrial K ( ATP ) ) channel opener diazoxide attenuated UV-induced keratinocytes cell death .
Reverse transcription PCR analysis revealed the expression of KIR 6.1 and SUR2B transcripts and immunohistochemical studies indicated the presence of KIR 6.1 and SUR2B proteins in the myocytes .
Expression of receptor activity-modifying protein 1 ( RAMP1 ) , calcitonin receptor-like receptor , Kir 6.1 and sulfonylurea receptor 2B ( SUR2B ) was also analysed .
The ATP-sensitive K(+) channel ( K ( ATP ) ) is a complex composed of an inwardly rectifying , pore-forming subunit ( Kir 61 and Kir 62 ) and the sulfonylurea receptor ( SUR1 and SUR2 ) .
Quantitative PCR showed that Kir 6.1 gene expression was upregulated by almost 22-fold , whereas SUR2B was downregulated by threefold after inflammation .
Single-channel analysis , after coexpression of SUR2B , Kir 6.1 , and Kir 6.2 , revealed the existence of five distinct populations with differing single-channel current amplitudes .
The model indicates that the central hole can readily accommodate the transmembrane domains of the Kir tetramer , suggests a location for the first transmembrane domains of SUR2B ( which are absent in Sav1866 ) and suggests the relative orientation of the SUR and Kir6.2 subunits .
The K-cell lines also express relatively low levels of Kir 6.1 , Kir 6.2 , SUR1 , and SUR2 suggesting secretion is independent of K ( ATP ) channels .
Our results indicate that native KATP channels in mouse vas deferens myocytes are a heterocomplex of KIR 6.1 channels and SUR2B subunits .
A dimeric Kir 6.1-Kir 6.2 construct expressed with SUR2B had a single-channel conductance intermediate between that of either Kir 6.2 or Kir 6.1 expressed with SUR2B .
Thus decreased motility of the colon during inflammation may be associated with changes in the transcriptional regulation of Kir 6.1 and SUR2B gene expression .
Two subunits of cardiac K ( ATP ) channel ( SUR2A and kir 62 ) were purchased as indicators and showed significantly decreased in both diabetic rats and high glucose treated rat cardiac myocytes .
We adopted an RT-PCR strategy to identify , in AEC , cDNA transcripts for Kir channels ( Kir61 or 62 ) and sulfonylurea receptors ( SUR1 , 2A , or 2B ) forming K ( ATP ) channels .
KCNQ1-KCNQ3 ) and nine Kir channel alpha-subunits ( Kir11 , Kir22 , Kir31-Kir34 , Kir41 , Kir61 , Kir6 2 ) were found .
KCNQ1-KCNQ3 ) and for five different Kir channel alpha-subunits ( Kir11 , Kir23 , Kir32 , Kir33 , Kir62 ) were found .
For example , native KATP channels appear to be a complex of a regulatory protein containing the SU-binding site [sulfonylurea receptor ( SUR ) ] and an inward-rectifying K+ channel ( Kir ) serving as a pore-forming subunit .
In the absence of Mg(2+) , the stilbene disulphonate , DIDS , irreversibly inhibits K ( ATP ) channels by binding to the Kir subunit .
We recently engineered a series of transgenic ( TG ) mice overexpressing an ATP-insensitive inward rectifying K(+) channel protein ( Kir ) 6.2 mutant ( Kir6.2[DeltaN30 , K185Q] ) or the accessory sulfonylurea receptor ( SUR ) 2A ( FLAG-SUR2A ) or SUR1 ( FLAG-SUR1 ) subunits of the K ( ATP ) channel , under transcriptional control of the alpha-myosin heavy chain promoter .
The Kir 6.0 family consists of two known members , Kir 6.1 and Kir 6.2 , with distinct functional properties .
ATP-sensitive potassium channels ( K ( ATP ) channels ) are composed of sulfonylurea receptors ( SURs ) and potassium inward rectifiers ( Kir ( 6 .
It seems that these NBFs play an essential role in conferring the MgADP and KCO sensitivity to the channel , whereas the Kir channel subunit itself possesses the ATP-sensing mechanism as an intrinsic property .
ATP-sensitive potassium channels are an octomeric complex of four pore-forming subunits of the Kir 6.0 family and four sulfonylurea receptors .
The analysis of the structure of the genes encoding K ( ATP ) channels that are made of four Kir subunits ( forming the ionic pore ) and four regulatory SUR subunits ( that contain the binding site for antidiabetic sulfonylureas ) allowed to several subclasses of those ionic channels to be described :
The expression of mRNA for voltage-dependent ( Kv ) and inward-rectifying K channels ( Kir ) was studied in clonal rat somato-mammotroph cells ( GH3/B6 cells ) and rat pituitary using reverse transcription-polymerase chain reaction ( RT-PCR ) .
Kir 6.1 , and Kir 6.2 dominant negative mutants were without effect on an inwardly rectifying potassium channel from a different family , Kir 2.1 .
In the cell-attached configuration , pinacidil activated channels with a conductance similar to that of KIR 6.1 .
Additional PKC consensus sites exist on both Kir and the larger sulfonylurea receptor ( SUR ) subunits .
By precisely comparing the functional properties of the SUR2A/Kir6.2 and the SUR2B/Kir6.1 channels , we shall show that the single-channel characteristics and pharmacological properties of SUR/Kir6.0 channels are determined by Kir and SUR subunits , respectively , while responses to intracellular nucleotides are determined by both SUR and Kir subunits .
Voltage-activated K+ channels ( Kv ) are encoded by the Kv gene family , Ca(2+) -activated K+ channels ( BKCa ) are encoded by the slo gene , inward rectifiers ( KIR ) by Kir2.0 , and ATP-sensitive K+ channels ( KATP ) by Kir6.0 and sulphonylurea receptor genes .
These results suggest a novel activity of aprindine to enhance K ( ATP ) currents by inhibiting proteasomal degradation of Kir 6.2 channels , which may be beneficial in the setting of cardiac ischemia .
ATP-sensitive K(+) ( K ( ATP ) ) channels , composed of inward rectifier K(+) ( Kir ) 6 .
ATP-regulated ( K ( ATP ) ) channels are formed by an inward rectifier pore-forming subunit ( Kir ) and a sulfonylurea ( glibenclamide ) -binding protein , a member of the ATP binding cassette family ( sulfonylurea receptor ( SUR ) or cystic fibrosis transmembrane conductance regulator ) .
It remains to be determined what are the molecular connections between the SUR and Kir subunits that enable this unique complex to work as a functional KATP channel .
X in a manner depending on the Kir subtype and on the integrity of the cell .
The sulfonylurea receptor ( SUR ) subunits are targets for drugs that are inhibitors or openers of the KATP channels , while the inwardly rectifying K+ ( Kir ) subunits form the ion channel .
Kir 6.1 was localized to the plasma membrane , whereas Kir 6.2 was mainly detected in the cytosol by immunohistochemistry .
The transgene expression of the K ( ATP ) channel was examined by reverse transcription-polymerase chain reaction ( RT-PCR ) in rats transfected with cDNA of Kir 6.1 and 6.2 .
K ( ATP ) channels are composed of sulphonylurea receptors ( SURs ) and potassium inward rectifiers ( Kir ( 6 .
Other types of Kir channel ( Kir11 , Kir21 and Kir41 ) were also irreversibly blocked by DIDS , suggesting that these channels may share common binding sites for these stilbene disulphonates .
In conclusion , Kir 6.1 and Kir 6.2 readily coassemble to produce functional channels , and such phenomena may contribute to the diversity of nucleotide-regulated potassium currents seen in native tissues .
After the coexpression of Kir 6.1 and Kir 6.2 , Kir 6.1 can be coimmunoprecipitated with isoform-specific Kir 6.2 antisera and vice versa .
During conventional whole-cell recording , pinacidil elicited an inward current that was suppressed by glibenclamide , a sulfonylurea agent , and by U-37883A , a selective KIR 6.1 blocker .
These channels are heteromultimers composed with a 4 : 4 stoichiometry of an inwardly rectifying K+ channel ( KIR ) subunit 6 .
To study the specificity of the taurine sensitivity , intracellular taurine was tested on several members of the Kir family expressed in Xenopus oocytes .
ATP-sensitive potassium channels ( K ( ATP ) ) , unlike other inwardly rectifying potassium ( Kir ) channels , require two structurally diverse subunits to form functional channels :
Vasodilation to increased external K+ involves KIR channels .
The purpose of this study was to investigate the subunit type of K ( ATP ) channel , that is , the combinations of the Kir subunit and the SUR subunit in the human corporal smooth muscle and determine whether the electrophysiological kinetics and pharmacological properties of K ( ATP ) channels meet the subunit characteristics of the ion channel .
The K ( ATP ) channels consist of 4 pore-forming inward rectifier K(+) channel ( Kir ) subunits and 4 regulatory sulfonylurea receptors ( SUR ) .
ATP-sensitive K(+) ( KATP ) channels , which are composed of KIR 6 .
Coexpression of S1-WT and S1-ND generated current components with intermediate spermine sensitivities indicating the presence of channel populations containing both types of Kir subunits at all possible stoichiometries .
MRNA for both Kir 6.1 and 6.2 were detected by RT-PCR .
Four regulatory sulfonylurea receptor ( SUR ) embracing four poreforming inwardly rectifying potassium channel ( Kir ) .