Sulphonylurea receptor 2B and Kir6.1 form a sulphonylurea‐sensitive but ATP‐insensitive K+ channel.

Yamada, Mitsuhiko; Isomoto, Shojiro; Matsumoto, Shigeto; Kondo, Chikako; Shindo, Takashi; Horio, Yoshiyuki; Kurachi, Yoshihisa

doi:10.1113/jphysiol.1997.sp021963

Cited by 357 publications

(324 citation statements)

References 17 publications

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“…The Kir6 tetrameric complex forms the channel's pore structure whereas the SUR (SUR1, SUR2A, or SUR2B) tetramer confers its nucleotide sensitivity and aspects of its pharmacology. Kir6.1 and SUR2B subunits form vascular K ATP channels (Li et al, 2003), which are activated by ATP and nucleotide diphosphates (Yamada et al, 1997). There is immunological evidence that Kir6.1 subunits may also contribute to mitochrondrial K ATP channels (Cuong et al, 2005;Singh et al, 2003), but this interpretation has been challenged (Foster et al, 2008).…”

Section: Physiological Significancementioning

confidence: 99%

Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium

Yang

Zhang

Hughes

2008

Experimental Eye Research

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Previously, we demonstrated that the inwardly rectifying K + (Kir) channel subunit Kir7.1 is highly expressed in bovine and human retinal pigment epithelium (RPE). The purpose of this study was to determine whether any of the 14 other members of the Kir gene family are expressed in native human RPE. Conventional reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that in addition to Kir7.1, 7 other Kir channel subunits (Kir1.1, Kir2.1, Kir2.2, Kir3.1, Kir3.4, Kir4.2 and Kir6.1) are expressed in the RPE, whereas in neural retina, all 14 of the Kir channel subunits examined are expressed. The identities of RT-PCR products in the RPE were confirmed by DNA sequencing. Real-time RT-PCR analysis showed, however, that transcripts of these channels are significantly less abundant than Kir7.1 in the RPE. Western blot analysis of the Kir channel subunits detected in the RPE by RT-PCR revealed the expression of Kir2.1, Kir3.1, Kir3.4, Kir4.2, Kir6.1, and possibly Kir2.2, but not Kir1.1, in both human RPE and neural retina. Our results indicate that human RPE expresses at least 5 other Kir channel subtypes in addition to Kir7.1, suggesting that multiple members of the Kir channel family may function in this epithelium.

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Section: Physiological Significancementioning

confidence: 99%

Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium

Yang

Zhang

Hughes

2008

Experimental Eye Research

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“…It is possible that the differences in sensitivity to PNU37883A shown by Kir6.1 and Kir6.2 may reflect differences in the intrinsic gating of the channels. Channels containing Kir6.2 are activated by depletion of ATP, whereas those containing Kir6.1 are not (Yamada et al, 1997). Previous analysis of chimeric Kir6.1/Kir6.2 channels mapped the residues responsible for spontaneous opening, in the absence of ATP, to two short regions of the Kir6.0 subunit; nine residues in the aminoterminal region and six in the proximal carboxy-terminal region (Kondo et al, 1998).…”

Section: H Kovalev Et Almentioning

confidence: 99%

“…The pharmacological differences between K ATP channels recorded in different tissues have been attributed to differing combinations of Kir6.0 and SUR subunits. For example, the pancreatic K ATP channel is Kir6.2/SUR1 (Inagaki et al, 1995b), the cardiac channel is Kir6.2/SUR2A (Inagaki et al, 1996) and the vascular channel is attributed to Kir6.1/ SUR2B (Yamada et al, 1997). In addition to ATP, channel opening can be inhibited pharmacologically by the application of sulphonylureas such as glibenclamide (Sturgess et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

Molecular analysis of the subtype‐selective inhibition of cloned K_ATP channels by PNU‐37883A

Kovalev

Quayle

Kamishima

et al. 2004

British J Pharmacology

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1 In this study, we have used Kir6.1/Kir6.2 chimeric proteins and current recordings to investigate the molecular basis of PNU-37883A inhibition of cloned K ATP channels. 2 Rat Kir6.1, Kir6.2 and Kir6.1/Kir6.2 chimeras were co-expressed with either SUR2B or SUR1, following RNA injection into Xenopus oocytes, and fractional inhibition of K ATP currents by 10 mM PNU-37883A reported. 3 Channels containing Kir6.1/SUR2B were more sensitive to inhibition by PNU-37883A than those containing Kir6.2/SUR2B (mean fractional inhibition: 0.70, cf. 0.07). 4 On expression with SUR2B, a chimeric channel with the Kir6.1 pore and the Kir6.2 amino-and carboxy-terminal domains was PNU-37883A insensitive (0.06). A chimera with the Kir6.1 carboxyterminus and Kir6.2 amino-terminus and pore was inhibited (0.48). These results, and those obtained with other chimeras, suggest that the C-terminus is an important determinant of PNU-37883A inhibition of Kir6.1. Similar results were seen when constructs were co-expressed with SUR1. Further chimeric constructs localised PNU-37883A sensitivity to an 81 amino-acid residue section in the Kir6.1 carboxy-terminus. 5 Our data show that structural differences between Kir6.1 and Kir6.2 are important in determining sensitivity to PNU-37883A. This compound may prove useful in probing the structural and functional differences between the two channel subtypes.

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“…In addition, we have isolated a cDNA encoding an isoform of SURI, designated SUR2, and have shown that coexpression of the SUR2 subunit and the Kir6.2 subunit in COSÍ cells reconstitutes KATP channel properties similar to those found in cardiac and skeletal muscle [5]. In addition, it has recently been shown that coexpression of the Kirö.l subunit and the SUR2B subunit, a variant form of SUR2, reconstitutes K + currents with properties similar to those of KATP channels in smooth muscle [6,7]. Thus, differing SUR subunits in combination with Kir6.0 subfamily subunits may account for the functional diversity of KATP channels.…”

Section: Introductionmentioning

confidence: 99%

Subunit stoichiometry of the pancreatic β‐cell ATP‐sensitive K⁺ channel

1997

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Sulphonylurea receptor 2B and Kir6.1 form a sulphonylurea‐sensitive but ATP‐insensitive K+ channel.

Cited by 357 publications

References 17 publications

Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium

Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium

Molecular analysis of the subtype‐selective inhibition of cloned K_ATP channels by PNU‐37883A

Subunit stoichiometry of the pancreatic β‐cell ATP‐sensitive K⁺ channel

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Sulphonylurea receptor 2B and Kir6.1 form a sulphonylurea‐sensitive but ATP‐insensitive K+ channel.

Cited by 357 publications

References 17 publications

Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium

Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium

Molecular analysis of the subtype‐selective inhibition of cloned KATP channels by PNU‐37883A

Subunit stoichiometry of the pancreatic β‐cell ATP‐sensitive K+ channel

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Molecular analysis of the subtype‐selective inhibition of cloned K_ATP channels by PNU‐37883A

Subunit stoichiometry of the pancreatic β‐cell ATP‐sensitive K⁺ channel