Channelpedia

Kir4.2

Description: potassium inwardly-rectifying channel, subfamily J, member 15
Gene: Kcnj15     Synonyms: Kir4.2, kcnj15, irkk

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Introduction


Experimental data


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Gene

RGD ID Chromosome Position Species
621662 11 35577083-35594291 Rat
731051 16 95479258-95521867 Mouse
731050 21 39628664-39673748 Human

Kcnj15 : potassium inwardly-rectifying channel, subfamily J, member 15


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Transcript

Acc No Sequence Length Source
NM_133321 n/A n/A NCBI
NM_019664 n/A n/A NCBI
NM_001039057 n/A n/A NCBI
NM_001039056 n/A n/A NCBI
NM_002243 n/A n/A NCBI
NM_170736 n/A n/A NCBI
NM_170737 n/A n/A NCBI

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Ontology

Accession Name Definition Evidence
GO:0005925 focal adhesion Small region on the surface of a cell that anchors the cell to the extracellular matrix and that forms a point of termination of actin filaments. IEA
GO:0005737 cytoplasm All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures. IEA
GO:0016021 integral to membrane Penetrating at least one phospholipid bilayer of a membrane. May also refer to the state of being buried in the bilayer with no exposure outside the bilayer. When used to describe a protein, indicates that all or part of the peptide sequence is embedded in the membrane. IEA
GO:0005886 plasma membrane The membrane surrounding a cell that separates the cell from its external environment. It consists of a phospholipid bilayer and associated proteins. IDA

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Interaction

Kir4.2 current in Xenopus oocytes can be blocked by Ba+ and Cs+ and weakly blocked by TEA in a voltage-dependent fashion. Intracellular acidification decreased mKir4.2 current in a reversible fashion, while activation of protein kinase C decreased mKir4.2 current in a manner that was not rapidly reversible. Incubation of oocytes in elevated [K+] produced a slowly developing enhancement of current.(Pearson [205])

Kir4.2 can form functional homotetramers, or heterotetramers with Kir5.1. (Pearson [205]) Kir5.1 converts Kir4.2 from a strong to a weak rectifier, rendering it sensitive to pHi, and suggesting that Kir5.1 plays a role in fine-tuning Kir4.2 activity. (Lam [206])


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Protein


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Structure

The residues involved in pHi sensing in Kir channels, such as the Inner Helix acidic residues (Xu [1035] and the ‘RKR triad’ (Schulte [1036], are identical in Kir4.1 and Kir4.2. (Lam [206]


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Distribution


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Expression

Kir4.2 channels are expressed in a variety of transporting epithelial within the kidney (Gosset [1028], Lourdel [1029], Shuck [1030], Tucker [1021]), liver (Hill [1031], Glowatzki [1032]), pancreas (Pessias [3]), bladder, stomach and lung (Thiery [1033], and an airway mucosal cell line (Wu [1034]).


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Functional


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Kinetics

mKir4.2 expressed in Xenopus oocytes displayed a large inwardly rectifying K+ current with inward rectification being intermediate between that of the strong inward rectifier Kir2.1 and the weak inward rectifier Kir1.1. (Pearson [205])


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Model


References

205

Nichols CG. et al. Expression of a functional Kir4 family inward rectifier K+ channel from a gene cloned from mouse liver.
J. Physiol. (Lond.), 1999 Feb 1 , 514 ( Pt 3) (639-53).

206

Lam HD. et al. Modulation of Kir4.2 rectification properties and pHi-sensitive run-down by association with Kir5.1.
Biochim. Biophys. Acta, 2006 Nov , 1758 (1837-45).

Briggs MM. et al. Cloning, expression, and localization of a rat hepatocyte inwardly rectifying potassium channel.
Am. J. Physiol. Gastrointest. Liver Physiol., 2002 Feb , 282 (G233-40).

Ruppersberg JP. et al. Subunit-dependent assembly of inward-rectifier K+ channels.
Proc. Biol. Sci., 1995 Aug 22 , 261 (251-61).

Wu JV. et al. An inwardly rectifying potassium channel in apical membrane of Calu-3 cells.
J. Biol. Chem., 2004 Nov 5 , 279 (46558-65).

Derst C. et al. pH gating of ROMK (K(ir)1.1) channels: control by an Arg-Lys-Arg triad disrupted in antenatal Bartter syndrome.
Proc. Natl. Acad. Sci. U.S.A., 1999 Dec 21 , 96 (15298-303).


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