ROMK

Potassium channel, inwardly rectifying subfamily J, member 1
Identifiers
Symbols	KCNJ1 ; KIR1.1; ROMK; ROMK1
External IDs	OMIM: 600359 MGI: 1927248 HomoloGene: 56764 IUPHAR: 429 ChEMBL: 1293292 GeneCards: KCNJ1 Gene
Gene ontology Molecular function • inward rectifier potassium channel activity • ATP binding • phosphatidylinositol-4,5-bisphosphate binding • ATP-activated inward rectifier potassium channel activity Cellular component • plasma membrane • integral component of plasma membrane • voltage-gated potassium channel complex Biological process • kidney development • tissue homeostasis • potassium ion transport • synaptic transmission • excretion • post-embryonic development • potassium ion import • regulation of ion transmembrane transport • renal sodium ion absorption • cardiovascular system development • regulation of G-protein activated inward rectifier potassium channel activity Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	3758	56379
Ensembl	ENSG00000151704	ENSMUSG00000041248
UniProt	P48048	O88335
RefSeq (mRNA)	NM_000220	NM_001168354
RefSeq (protein)	NP_000211	NP_001161826
Location (UCSC)	Chr 11: 128.84 – 128.87 Mb	Chr 9: 32.37 – 32.4 Mb
PubMed search

The renal outer medullary potassium channel (ROMK) is an ATP-dependent potassium channel (K_ir1.1) that transports potassium out of cells. It plays an important role in potassium recycling in the thick ascending limb (TAL) and potassium secretion in the cortical collecting duct (CCD) of the nephron. In humans, ROMK is encoded by the KCNJ1 (potassium inwardly-rectifying channel, subfamily J, member 1) gene.^[1][2][3] Multiple transcript variants encoding different isoforms have been found for this gene.^[4]

Function

Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. It is inhibited by internal ATP and probably plays an important role in potassium homeostasis. The encoded protein has a greater tendency to allow potassium to flow into a cell rather than out of a cell (hence the term "inwardly rectifying"). ROMK was identified as the pore forming component of mitoK_ATP channels that are known to have a critical role during stroke or other ischemic attacks in the protection against hypoxia-induced brain injury.^[4][5]

Clinical significance

Mutations in this gene have been associated with antenatal Bartter syndrome, which is characterized by salt wasting, hypokalemic alkalosis, hypercalciuria, and low blood pressure.^[4]

References

1. Ho K, Nichols CG, Lederer WJ, Lytton J, Vassilev PM, Kanazirska MV, Hebert SC (March 1993). "Cloning and expression of an inwardly rectifying ATP-regulated potassium channel". Nature 362 (6415): 31–8. doi:10.1038/362031a0. PMID 7680431.
2. Yano H, Philipson LH, Kugler JL, Tokuyama Y, Davis EM, Le Beau MM, Nelson DJ, Bell GI, Takeda J (May 1994). "Alternative splicing of human inwardly rectifying K+ channel ROMK1 mRNA". Mol. Pharmacol. 45 (5): 854–60. PMID 8190102.
3. Kubo Y, Adelman JP, Clapham DE, Jan LY, Karschin A, Kurachi Y, Lazdunski M, Nichols CG, Seino S, Vandenberg CA (December 2005). "International Union of Pharmacology. LIV. Nomenclature and molecular relationships of inwardly rectifying potassium channels". Pharmacol. Rev. 57 (4): 509–26. doi:10.1124/pr.57.4.11. PMID 16382105.
4. "Entrez Gene: potassium inwardly-rectifying channel".
5. "Mitochondrial ROMK channel is a molecular component of mitoK(ATP)".

Welling, P.A. and Kevin Ho, A Comprehensive Guide to ROMK: Form and Function in Health and Disease, Am J Physiol Renal Physiol. 2009 Oct;297(4):F849-63. (Review)

Further reading

• O'Connell AD, Leng Q, Dong K, et al. (2005). "Phosphorylation-regulated endoplasmic reticulum retention signal in the renal outer-medullary K+ channel (ROMK).". Proc. Natl. Acad. Sci. U.S.A. 102 (28): 9954–9. doi:10.1073/pnas.0504332102. PMC 1175014. PMID 15987778.
• Kubo Y, Adelman JP, Clapham DE, et al. (2005). "International Union of Pharmacology. LIV. Nomenclature and molecular relationships of inwardly rectifying potassium channels.". Pharmacol. Rev. 57 (4): 509–26. doi:10.1124/pr.57.4.11. PMID 16382105.
• Brochard K, Boyer O, Blanchard A, et al. (2009). "Phenotype-genotype correlation in antenatal and neonatal variants of Bartter syndrome.". Nephrol. Dial. Transplant. 24 (5): 1455–64. doi:10.1093/ndt/gfn689. PMID 19096086.
• Lee JR, Shieh RC (2009). "Structural changes in the cytoplasmic pore of the Kir1.1 channel during pHi-gating probed by FRET.". J. Biomed. Sci. 16 (1): 29. doi:10.1186/1423-0127-16-29. PMC 2672938. PMID 19272129.
• Nüsing RM, Pantalone F, Gröne HJ, et al. (2005). "Expression of the potassium channel ROMK in adult and fetal human kidney.". Histochem. Cell Biol. 123 (6): 553–9. doi:10.1007/s00418-004-0742-5. PMID 15895241.
• Cho JT, Guay-Woodford LM (2003). "Heterozygous mutations of the gene for Kir 1.1 (ROMK) in antenatal Bartter syndrome presenting with transient hyperkalemia, evolving to a benign course.". J. Korean Med. Sci. 18 (1): 65–8. PMC 3055000. PMID 12589089.
• Ji W, Foo JN, O'Roak BJ, et al. (2008). "Rare independent mutations in renal salt handling genes contribute to blood pressure variation.". Nat. Genet. 40 (5): 592–9. doi:10.1038/ng.118. PMC 3766631. PMID 18391953.
• Nozu K, Fu XJ, Kaito H, et al. (2007). "A novel mutation in KCNJ1 in a Bartter syndrome case diagnosed as pseudohypoaldosteronism.". Pediatr. Nephrol. 22 (8): 1219–23. doi:10.1007/s00467-007-0468-4. PMID 17401586.
• Lin D, Kamsteeg EJ, Zhang Y, et al. (2008). "Expression of tetraspan protein CD63 activates protein-tyrosine kinase (PTK) and enhances the PTK-induced inhibition of ROMK channels.". J. Biol. Chem. 283 (12): 7674–81. doi:10.1074/jbc.M705574200. PMID 18211905.
• Wang HR, Liu Z, Huang CL (2008). "Domains of WNK1 kinase in the regulation of ROMK1.". Am. J. Physiol. Renal Physiol. 295 (2): F438–45. doi:10.1152/ajprenal.90287.2008. PMC 2519181. PMID 18550644.
• Gerhard DS, Wagner L, Feingold EA, et al. (2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).". Genome Res. 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMC 528928. PMID 15489334.
• Yoo D, Kim BY, Campo C, et al. (2003). "Cell surface expression of the ROMK (Kir 1.1) channel is regulated by the aldosterone-induced kinase, SGK-1, and protein kinase A.". J. Biol. Chem. 278 (25): 23066–75. doi:10.1074/jbc.M212301200. PMID 12684516.
• Cha SK, Hu MC, Kurosu H, et al. (2009). "Regulation of renal outer medullary potassium channel and renal K(+) excretion by Klotho.". Mol. Pharmacol. 76 (1): 38–46. doi:10.1124/mol.109.055780. PMC 2701452. PMID 19349416.
• Nanazashvili M, Li H, Palmer LG, et al. (2007). "Moving the pH gate of the Kir1.1 inward rectifier channel.". Channels (Austin) 1 (1): 21–8. doi:10.4161/chan.3707. PMID 19170254.
• Liu Z, Wang HR, Huang CL (2009). "Regulation of ROMK channel and K+ homeostasis by kidney-specific WNK1 kinase.". J. Biol. Chem. 284 (18): 12198–206. doi:10.1074/jbc.M806551200. PMC 2673288. PMID 19244242.
• Yoo D, Flagg TP, Olsen O, et al. (2004). "Assembly and trafficking of a multiprotein ROMK (Kir 1.1) channel complex by PDZ interactions.". J. Biol. Chem. 279 (8): 6863–73. doi:10.1074/jbc.M311599200. PMID 14604981.
• Tobin MD, Tomaszewski M, Braund PS, et al. (2008). "Common variants in genes underlying monogenic hypertension and hypotension and blood pressure in the general population.". Hypertension 51 (6): 1658–64. doi:10.1161/HYPERTENSIONAHA.108.112664. PMID 18443236.
• He G, Wang HR, Huang SK, Huang CL (2007). "Intersectin links WNK kinases to endocytosis of ROMK1.". J. Clin. Invest. 117 (4): 1078–87. doi:10.1172/JCI30087. PMC 1821066. PMID 17380208.
• Murthy M, Cope G, O'Shaughnessy KM (2008). "The acidic motif of WNK4 is crucial for its interaction with the K channel ROMK.". Biochem. Biophys. Res. Commun. 375 (4): 651–4. doi:10.1016/j.bbrc.2008.08.076. PMID 18755144.
• Lazrak A, Liu Z, Huang CL (2006). "Antagonistic regulation of ROMK by long and kidney-specific WNK1 isoforms.". Proc. Natl. Acad. Sci. U.S.A. 103 (5): 1615–20. doi:10.1073/pnas.0510609103. PMC 1360592. PMID 16428287.

External links

• ROMK1 protein, human at the US National Library of Medicine Medical Subject Headings (MeSH)
• NDI terminology page

This article incorporates text from the United States National Library of Medicine, which is in the public domain.