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Kir7.1

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Target id: 443

Nomenclature: Kir7.1

Family: Inwardly rectifying potassium channels (KIR)

Contents:

Gene and Protein Information Click here for help
Species TM P Loops AA Chromosomal Location Gene Symbol Gene Name Reference
Human 2 1 360 2q37.1 KCNJ13 potassium inwardly rectifying channel subfamily J member 13 2,5,10
Mouse 2 0 360 1 Kcnj13 potassium inwardly-rectifying channel, subfamily J, member 13
Rat 2 1 360 9q35 Kcnj13 potassium inwardly-rectifying channel, subfamily J, member 13 3
Previous and Unofficial Names Click here for help
potassium inwardly rectifying channel subfamily J member 13 | inward rectifier K(+) channel Kir7.1 | inward rectifier potassium channel 13 | IRK13 | Kir1.4 | potassium channel, inwardly rectifying subfamily J, member 13 | potassium inwardly-rectifying channel | potassium voltage-gated channel subfamily J member 13
Database Links Click here for help
Alphafold O60928 (Hs), P86046 (Mm), O70617 (Rn)
CATH/Gene3D 2.60.40.1400
ChEMBL Target CHEMBL2146349 (Hs)
Ensembl Gene ENSG00000115474 (Hs), ENSMUSG00000079436 (Mm), ENSRNOG00000016057 (Rn)
Entrez Gene 3769 (Hs), 100040591 (Mm), 94341 (Rn)
Human Protein Atlas ENSG00000115474 (Hs)
KEGG Gene hsa:3769 (Hs), mmu:100040591 (Mm), rno:94341 (Rn)
OMIM 603208 (Hs)
Orphanet ORPHA159740 (Hs)
Pharos O60928 (Hs)
RefSeq Nucleotide NM_002242 (Hs), NM_001110227 (Mm), NM_053608 (Rn)
RefSeq Protein NP_002233 (Hs), NP_001103697 (Mm), NP_446060 (Rn)
UniProtKB O60928 (Hs), P86046 (Mm), O70617 (Rn)
Wikipedia KCNJ13 (Hs)
Functional Characteristics Click here for help
Inward-rectifier current
Ion Selectivity and Conductance Click here for help
Species:  Human
Rank order:  Rb+ > K+ [0.043 - 0.055 pS] > Na+ > Cs+ > Li+
References:  3,5,13
Voltage Dependence Click here for help
  V0.5 (mV)  τ (msec)  Reference  Cell type  Species 
Activation  - 0.7 – 1.7 3 Xenopus laevis oocyte Human
Inactivation  - -
Voltage Dependence Comments
Kir7.1 is voltage dependant, however unlike other Kir channels shows no crossover phenomenon (increasing in outward current as [K+o] increases) [5].

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Channel Blockers
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand
Sp.
Action
Value
Parameter
Concentration range (M)
Holding voltage (mV)
Reference
fampridine Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist - - 1x10-3 - 1x10-2 -100.0 5
⤷ Conc range: 1x10-3 - 1x10-2 M [5]
Holding voltage: -100.0 mV
Ba2+ Click here for species-specific activity table Hs Antagonist 3.2 pKi - -100.0 3,5-6,10
⤷ pKi 3.2 [3,5-6,10]
Holding voltage: -100.0 mV
Cs+ Click here for species-specific activity table Hs Antagonist 1.6 pKi - -100.0 3,5,10
⤷ pKi 1.6 [3,5,10]
Holding voltage: -100.0 mV
Channel Blocker Comments
ML-111 blocks human Kir7.1 channel activity by >50% at 10 micromolar concentration [1].

VU573 blocks human Kir7.1 channel activity by >50% at 5 micromolar concentration [11].
Tissue Distribution Click here for help
Small intestine > stomach, kidney, brain, thyroid (medulla, hippocampus, corpus callosum > cerebellum, cortex, amygdala, substantia nigra, thalamus)
Species:  Human
Technique:  Northern Blot
References:  5,8,10
Retinal pigmented epithelium, iris pigmented epithelium
Species:  Human
Technique:  Western blot
References:  15
Retinal pigmented epithelium, iris pigmented epithelium.
Species:  Rat
Technique:  RT-PCR, immunohistochemistry
References:  6
Brain; cerebellum (purkinje cells), hippocampus (pyramidal cells) > dentate gyrus
Kidney; Thick ascending loop of Henle, distal convoluted tubule, cortical collecting duct, outer medullary collecting duct, inner medullary collecting duct.
Species:  Rat
Technique:  Immunohistochemistry
References:  5,9
Brain, lung, kidney, testis
Species:  Rat
Technique:  Northern blot, Western blot, Immunohistochemistry
References:  3,14
Thyroid follicular cells, intestine and choroid plexus epithelial cells.
Species:  Rat
Technique:  Immunohistochemistry, northern blot
References:  8
Secretory epithelial cells of the choroid plexus, neuroepithelium of the meninges, but not in central neurons or glia.
Species:  Rat
Technique:  In situ hybridisation
References:  3
Functional Assays Click here for help
Patch clamp of Kir7.1 transfected cells.
Species:  Rat
Tissue:  HEK, COS, CHO cells.
Response measured:  Current.
References:  5
Patch clamp.
Species:  Rat
Tissue:  Retinal pigment epithelial cells
Response measured:  Current
References:  6
Physiological Functions Click here for help
Maintains cellular resting potential near the potassium equilibrium potential. This function appears particularly prominent in the apical epithelia of secretory cells and may localise with Na+,K+-ATPase in thyroid follicular and choroid plexus epithelial cells.
Species:  None
Tissue:  Many
References:  2-3,5-6,8-10,13-14,16
Clinically-Relevant Mutations and Pathophysiology Click here for help
Disease:  Leber congenital amaurosis 16; LCA16
Synonyms: Amaurosis congenita of Leber
Leber congenital amaurosis [Orphanet: ORPHA65] [Disease Ontology: DOID:14791]
Disease Ontology: DOID:14791
OMIM: 614186
Orphanet: ORPHA65
References:  12
Disease:  Snowflake vitreoretinal degeneration; SVD
OMIM: 193230
Orphanet: ORPHA91496
References:  4,17
Biologically Significant Variant Comments
Three major, and many minor, variants of rat Kir7.1 mRNA have been found to arise from alternative splicing of non-coding exons in the 5' untranslated region. Tissue-specific variation in splicing patterns is widespread [7].

References

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1. Denton JS, Weaver CD, Lewis LM, Chauder BA, Lindsley CW. (2010) Discovery of a small molecule inhibitor of ROMK and Kir7.1. In Probe Reports from the NIH Molecular Libraries Program. (National Center for Biotechnology Information (US)) . [PMID:21433378]

2. Derst C, Döring F, Preisig-Müller R, Daut J, Karschin A, Jeck N, Weber S, Engel H, Grzeschik KH. (1998) Partial gene structure and assignment to chromosome 2q37 of the human inwardly rectifying K+ channel (Kir7.1) gene (KCNJ13). Genomics, 54 (3): 560-3. [PMID:9878260]

3. Döring F, Derst C, Wischmeyer E, Karschin C, Schneggenburger R, Daut J, Karschin A. (1998) The epithelial inward rectifier channel Kir7.1 displays unusual K+ permeation properties. J Neurosci, 18 (21): 8625-36. [PMID:9786970]

4. Hejtmancik JF, Jiao X, Li A, Sergeev YV, Ding X, Sharma AK, Chan CC, Medina I, Edwards AO. (2008) Mutations in KCNJ13 cause autosomal-dominant snowflake vitreoretinal degeneration. Am J Hum Genet, 82 (1): 174-80. [PMID:18179896]

5. Krapivinsky G, Medina I, Eng L, Krapivinsky L, Yang Y, Clapham DE. (1998) A novel inward rectifier K+ channel with unique pore properties. Neuron, 20 (5): 995-1005. [PMID:9620703]

6. Kusaka S, Inanobe A, Fujita A, Makino Y, Tanemoto M, Matsushita K, Tano Y, Kurachi Y. (2001) Functional Kir7.1 channels localized at the root of apical processes in rat retinal pigment epithelium. J Physiol (Lond.), 531 (Pt 1): 27-36. [PMID:11179389]

7. Nakamura N, Suzuki Y, Ikeda Y, Notoya M, Hirose S. (2000) Complex structure and regulation of expression of the rat gene for inward rectifier potassium channel Kir7.1. J Biol Chem, 275 (36): 28276-84. [PMID:10871613]

8. Nakamura N, Suzuki Y, Sakuta H, Ookata K, Kawahara K, Hirose S. (1999) Inwardly rectifying K+ channel Kir7.1 is highly expressed in thyroid follicular cells, intestinal epithelial cells and choroid plexus epithelial cells: implication for a functional coupling with Na+,K+-ATPase. Biochem J, 342 ( Pt 2): 329-36. [PMID:10455019]

9. Ookata K, Tojo A, Suzuki Y, Nakamura N, Kimura K, Wilcox CS, Hirose S. (2000) Localization of inward rectifier potassium channel Kir7.1 in the basolateral membrane of distal nephron and collecting duct. J Am Soc Nephrol, 11 (11): 1987-94. [PMID:11053473]

10. Partiseti M, Collura V, Agnel M, Culouscou JM, Graham D. (1998) Cloning and characterization of a novel human inwardly rectifying potassium channel predominantly expressed in small intestine. FEBS Lett, 434 (1-2): 171-6. [PMID:9738472]

11. Raphemot R, Lonergan DF, Nguyen TT, Utley T, Lewis LM, Kadakia R, Weaver CD, Gogliotti R, Hopkins C, Lindsley CW et al.. (2011) Discovery, characterization, and structure-activity relationships of an inhibitor of inward rectifier potassium (Kir) channels with preference for Kir2.3, Kir3.x, and Kir7.1. Front Pharmacol, 2: 75. [PMID:22275899]

12. Sergouniotis PI, Davidson AE, Mackay DS, Li Z, Yang X, Plagnol V, Moore AT, Webster AR. (2011) Recessive mutations in KCNJ13, encoding an inwardly rectifying potassium channel subunit, cause leber congenital amaurosis. Am J Hum Genet, 89 (1): 183-90. [PMID:21763485]

13. Shimura M, Yuan Y, Chang JT, Zhang S, Campochiaro PA, Zack DJ, Hughes BA. (2001) Expression and permeation properties of the K(+) channel Kir7.1 in the retinal pigment epithelium. J Physiol (Lond.), 531 (Pt 2): 329-46. [PMID:11230507]

14. Suzuki Y, Yasuoka Y, Shimohama T, Nishikitani M, Nakamura N, Hirose S, Kawahara K. (2003) Expression of the K+ channel Kir7.1 in the developing rat kidney: role in K+ excretion. Kidney Int, 63 (3): 969-75. [PMID:12631077]

15. Yang D, Zhang X, Hughes BA. (2008) Expression of inwardly rectifying potassium channel subunits in native human retinal pigment epithelium. Exp Eye Res, 87 (3): 176-83. [PMID:18653180]

16. Yasuda K, Shimura M, Nakazawa T, Sato H, Tomita H, Sugano E, Tamai M. (2003) Expression and functional properties of unique inward rectifier K+ channel Kir7.1 in the porcine iris and retinal pigment epithelium. Curr Eye Res, 27 (5): 279-87. [PMID:14562164]

17. Zhang W, Zhang X, Wang H, Sharma AK, Edwards AO, Hughes BA. (2013) Characterization of the R162W Kir7.1 mutation associated with snowflake vitreoretinopathy. Am J Physiol, Cell Physiol, 304 (5): C440-9. [PMID:23255580]

Contributors

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How to cite this page

Adelman JP, Clapham DE, Hibino H, Inanobe A, Jan LY, Karschin A, Kubo Y, Kurachi Y, Lazdunski M, Miki T, Nichols CG, Palmer LG, Pearson WL, Sackin H, Seino S, Slesinger PA, Tucker S, Vandenberg CA. Inwardly rectifying potassium channels (KIR) in GtoPdb v.2023.1. IUPHAR/BPS Guide to Pharmacology CITE. 2023; 2023(1). Available from: https://doi.org/10.2218/gtopdb/F74/2023.1.