Channelpedia

Kir4.1

Description: potassium inwardly-rectifying channel, subfamily J, member 10
Gene: Kcnj10     Synonyms: Kir4.1, kcnj10, BIR10, BIRK-1

Edit - History

Introduction

The Kir channel family comprises more than 15 members that fall into seven subfamilies (Kir1.x through Kir7.x) (Kubo et al., 2005 [1008]).

KCNJ10 (also known as KIR1.2; KIR4.1; SESAME; BIRK-10; KCNJ13-PEN) encodes Kir4.1, potassium inwardly-rectifying channel, subfamily J, member 10, characterized by having a greater tendency to allow potassium to flow into, rather than out of, a cell. The encoded protein may form a heterodimer with another potassium channel protein and may be responsible for the potassium buffering action of glial cells in the brain. Mutations in this gene have been associated with seizure susceptibility of common idiopathic generalized epilepsy syndromes.

http://www.ncbi.nlm.nih.gov/gene/3766


Experimental data


Edit

Gene

RGD ID Chromosome Position Species
61822 13 88341102-88370591 Rat
62113 1 174271341-174304216 Mouse
731912 1 160007257-160040051 Human

Kcnj10 : potassium inwardly-rectifying channel, subfamily J, member 10


Edit

Transcript

Acc No Sequence Length Source
NM_031602 n/A n/A NCBI
NM_001039484 n/A n/A NCBI
NM_002241 n/A n/A NCBI

Edit

Ontology

Accession Name Definition Evidence
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:0016020 membrane Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins. IEA

Edit - History

Interaction

Tricyclic antidepressants (TCAs) influence the astroglial Kir4.1 channels expressed in HEK293T cells. Su et al. [202] demonstrated that nortriptyline and other TCAs, including amitriptyline, desipramine, and imipramine, inhibit homomeric Kir4.1 channels in a voltage- and time-dependent fashion.

Unlike other Kir family members, heteromultimerization of inter-subfamily members Kir4.1 and Kir5.1 leads to a channel with distinct functional properties (Casamassima[1018], Konstas [1019], Pessia [1020], Tanemoto [1013], Tucker [1021], Xu [1022], Yang [1023]). Of particular interest in these newly emerging properties is the enhanced sensitivity to intracellular pH (pKa 7.45), allowing the heteromeric Kir4.1–Kir5.1 channel to detect pH changes at physiological levels (Pessia [1020], Xu [1022], Yang [1023], Xui [1024]).


Edit

Protein


Edit

Structure


Edit

Distribution

Kir4.1 alone exists at the end-feet of retinal Mueller cells, and both Kir4.1 and Kir5.1, are detected in the cell body (Ishii [1010]).


Edit - History

Expression

It was shown that, among them, Kir4.1 and Kir5.1 are expressed predominantly in brain astrocytes and retinal Muller cells (Takumi et al., 1995 [1009]; Ishii et al., 1997 [1010], 2003; Poopalasundaram et al., 2000 [1011]; Hibino et al., 2004 [1012]).

The Kir4.1 and Kir5.1 subunits are expressed in the proximal convoluted tubule, the distal convoluted tubule and the cortical collecting duct of the kidney (Tucker [1019], Tanemoto [1013], Tanemoto [1027]).


Edit - History

Functional

Astroglial Kir channels are either homotetramers of Kir4.1 or heterotetramers of Kir4.1 and Kir5.1, both of which constitutively allow large inward K+ currents at potentials negative to EK and small, but significant, outward K+ currents at those positive to EK (Takumi et al., 1995 [1009]; Ishii et al., 1997 [1010]; Tanemoto et al., 2000 [1013]; Higashi et al., 2001 [1014]). Thus, depending on the difference between local EK and the membrane potential of astrocytes, these Kir channels can mediate either absorption or extrusion of K+ across the astroglial cell membrane and thus can act as the spatial K+-buffering current. (Su [202])

In addition, Kir4.1 channel and the water channel, aquaporin-4, are colocalized in certain membrane domains of brain astrocytes and Muller cells, suggesting that spatial K+ buffering may couple with water movement across the astroglial membrane (Nagelhus et al., 1999 [1015]; Amiry-Moghaddam et al., 2003 [1016]; Puwarawuttipanit et al., 2006 [1017]).

Kir4.1 and Kir5.1 subunits are expressed in the kidney, eye and brainstem suggests that the channel may be a candidate molecule for the regulation of K+ homeostasis and central CO2 chemoreception (Pessia [1020], Yang [1023], Jiang [1025], Wu [1026]).


Edit

Kinetics


Edit

Model


References

203

Rojas A et al. Protein kinase C dependent inhibition of the heteromeric Kir4.1-Kir5.1 channel.
Biochim. Biophys. Acta, 2007 Sep , 1768 (2030-42).

Ishii M et al. Differential expression and distribution of Kir5.1 and Kir4.1 inwardly rectifying K+ channels in retina.
Am. J. Physiol., Cell Physiol., 2003 Aug , 285 (C260-7).

Tanemoto M et al. In vivo formation of a proton-sensitive K+ channel by heteromeric subunit assembly of Kir5.1 with Kir4.1.
J. Physiol. (Lond.), 2000 Jun 15 , 525 Pt 3 (587-92).

Amiry-Moghaddam M et al. An alpha-syntrophin-dependent pool of AQP4 in astroglial end-feet confers bidirectional water flow between blood and brain.
Proc. Natl. Acad. Sci. U.S.A., 2003 Feb 18 , 100 (2106-11).

Konstas AA et al. Identification of domains that control the heteromeric assembly of Kir5.1/Kir4.0 potassium channels.
Am. J. Physiol., Cell Physiol., 2003 Apr , 284 (C910-7).

Xu H et al. Modulation of kir4.1 and kir5.1 by hypercapnia and intracellular acidosis.
J. Physiol. (Lond.), 2000 May 1 , 524 Pt 3 (725-35).

Tanemoto M et al. PDZ binding motif-dependent localization of K+ channel on the basolateral side in distal tubules.
Am. J. Physiol. Renal Physiol., 2004 Dec , 287 (F1148-53).


Edit

Credits

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/ionchannels/50/ , accessed on [date]