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Gene Review

Kcnj1  -  potassium channel, inwardly rectifying...

Rattus norvegicus

Synonyms: ATP-regulated potassium channel ROM-K, ATP-sensitive inward rectifier potassium channel 1, Inward rectifier K(+) channel Kir1.1, KAB-1, Kcnj, ...
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Disease relevance of Kcnj1

  • The inwardly rectifying K+ channel, Kir1.1 (ROMK) appears to form the pore of the channel, and mutations in Kir1.1 are responsible for Bartter syndrome [1].
  • We have analyzed the transcriptional regulation of K(ATP) genes in rat kidney following transient renal ischemia.We observed that mRNA expression level was down-regulated for Kir1.1 and Kir4.1 potassium channels between 24 and 120 h after ischemia [2].
  • These results suggest that overexpression of ROMK and BSC-1 in the thick ascending limb combined with a deficiency in renal formation of 20-HETE may predispose Dahl S rats fed a high-salt diet to Na+ retention and hypertension [3].
  • Regulation of ROMK and channel-inducing factor (CHIF) in acute renal failure due to ischemic reperfusion injury [4].
  • In the thick ascending limb of Henle's loop, a decrease in ROMK and BSC-1 could result in decreased reabsorption of NaCl, a finding associated with hypokalemia [5].

High impact information on Kcnj1

  • Based on sequence homology with cloned inwardly rectifying K+ channels, ROMK1 (ref. 11) and IRK1 (ref. 12), we have isolated a complementary DNA for a G-protein-coupled inwardly rectifying K+ channel (GIRK1) from rat heart [6].
  • 1. Reconstitution studies in Xenopus oocytes reveal that L-WNK1 significantly inhibits Kir1.1 by reducing cell surface localization of the channel [7].
  • Acute dietary potassium loading increases the relative abundance of KS-WNK1 to L-WNK1 transcript and protein in the kidney, indicating that physiologic up-regulation of Kir1.1 activity involves a WNK1 isoform switch and KS-WNK1-mediated release from L-WNK1 inhibition [7].
  • We have shown that maltose-binding fusion proteins (MBP) containing the COOH termini of K(ATP) channels (Kir1.1, Kir6.1, and Kir6.2) form functional tetramers that directly bind at least two ATP molecules with negative cooperativity [8].
  • A role for head group charge was supported by polycations (neomycin, spermine, and polylysine) reversing the effect of PIP2 on TNP-ATP binding to the Kir1.1 channel COOH terminal fusion protein [8].

Chemical compound and disease context of Kcnj1


Biological context of Kcnj1


Anatomical context of Kcnj1

  • Our previous studies showed that co-expression of ROMK2, but not ROMK1 or ROMK3, with rat SUR2B in oocytes generated glibenclamide-sensitive K(+) currents [13].
  • A phosphorylation-dependent export structure in ROMK (Kir 1.1) channel overrides an endoplasmic reticulum localization signal [10].
  • In addition, two early inframe stop mutations could be rescued by aminoglycosides, resulting in full-length ROMK and correct trafficking to the plasma membrane in a subset of transfected cells [12].
  • We found that ROMK abundance in kidney cortex and CCDs was reduced in rats fed a K+-restricted diet compared with rats fed the control K+ diet [11].
  • METHODS: Mutated ROMK potassium channels were expressed in Xenopus oocytes and a human kidney cell line and analyzed by two electrode voltage clamp analysis, immunofluorescence, and Western blot analysis [12].

Associations of Kcnj1 with chemical compounds

  • Moreover, c-Src and ROMK are coexpressed in the same nephron segment [14].
  • Treatment of the CCD from rats on a HK diet with phenylarsine oxide (PAO) decreases the positive staining in the plasma/subapical membrane and increases the ROMK staining in the intracellular compartment [14].
  • An amino acid triplet in the NH2 terminus of rat ROMK1 determines interaction with SUR2B [13].
  • We constructed a series of hemagglutinin-tagged ROMK1 NH(2)-terminal deletion and substitution mutants and examined glibenclamide-sensitive K(+) currents in oocytes when co-expressed with SUR2B [13].
  • These studies identified an amino acid triplet "IRA" within the conserved segment in the NH(2) terminus of ROMK1 and ROMK3 that blocks the ability of SUR2B to confer glibenclamide sensitivity to the expressed K(+) currents [13].

Regulatory relationships of Kcnj1

  • We conclude that O(2)(-) and related products play a role in mediating the effect of low K intake on c-Src expression and in suppressing ROMK channel activity and renal K secretion [15].
  • The selective adenosine A2a-receptor agonist CGS 21680 induced enhanced mRNA expression of both Kv1.3 and ROMK1, as well as an elevation of Kv1.3 protein [16].

Other interactions of Kcnj1


Analytical, diagnostic and therapeutic context of Kcnj1

  • In vitro co-translation and immunoprecipitation studies with hemagglutinin-tagged ROMK mutants and SUR2B indicted that direct interaction between these two proteins is required for glibenclamide sensitivity of induced K(+) currents in oocytes [13].
  • Using RT-PCR, we have identified a new set of ROMK isoforms in rat kidney that are generated by the deletion of a region within the ROMK core sequence that is identifiable as a typical mammalian intron [18].
  • Using patch clamp techniques, we have investigated the regulation of ROMK1 with particular emphasis on phosphorylation/dephosphorylation processes [19].
  • Using immunoblotting, a more than threefold increase in immunoreactive ROMK levels was observed in the outer medulla after dDAVP infusion [20].
  • ROMK expression was reduced in the cortex and was completely abolished in the medulla at 48 to 72 hours of reperfusion [4].


  1. Intrinsic sensitivity of Kir1.1 (ROMK) to glibenclamide in the absence of SUR2B. Implications for the identity of the renal ATP-regulated secretory K+ channel. Konstas, A.A., Dabrowski, M., Korbmacher, C., Tucker, S.J. J. Biol. Chem. (2002) [Pubmed]
  2. Regulation of ATP-sensitive potassium channel mRNA expression in rat kidney following ischemic injury. Sgard, F., Faure, C., Drieu la Rochelle, C., Graham, D., O'Connor, S.E., Janiak, P., Besnard, F. Biochem. Biophys. Res. Commun. (2000) [Pubmed]
  3. Elevated BSC-1 and ROMK expression in Dahl salt-sensitive rat kidneys. Hoagland, K.M., Flasch, A.K., Dahly-Vernon, A.J., dos Santos, E.A., Knepper, M.A., Roman, R.J. Hypertension (2004) [Pubmed]
  4. Regulation of ROMK and channel-inducing factor (CHIF) in acute renal failure due to ischemic reperfusion injury. Gimelreich, D., Popovtzer, M.M., Wald, H., Pizov, G., Berlatzky, Y., Rubinger, D. Kidney Int. (2001) [Pubmed]
  5. Potassium restriction downregulates ROMK expression in rat kidney. Mennitt, P.A., Frindt, G., Silver, R.B., Palmer, L.G. Am. J. Physiol. Renal Physiol. (2000) [Pubmed]
  6. Primary structure and functional expression of a rat G-protein-coupled muscarinic potassium channel. Kubo, Y., Reuveny, E., Slesinger, P.A., Jan, Y.N., Jan, L.Y. Nature (1993) [Pubmed]
  7. WNK1 kinase isoform switch regulates renal potassium excretion. Wade, J.B., Fang, L., Liu, J., Li, D., Yang, C.L., Subramanya, A.R., Maouyo, D., Mason, A., Ellison, D.H., Welling, P.A. Proc. Natl. Acad. Sci. U.S.A. (2006) [Pubmed]
  8. Nucleotides and phospholipids compete for binding to the C terminus of KATP channels. MacGregor, G.G., Dong, K., Vanoye, C.G., Tang, L., Giebisch, G., Hebert, S.C. Proc. Natl. Acad. Sci. U.S.A. (2002) [Pubmed]
  9. K depletion increases protein tyrosine kinase-mediated phosphorylation of ROMK. Lin, D.H., Sterling, H., Lerea, K.M., Welling, P., Jin, L., Giebisch, G., Wang, W.H. Am. J. Physiol. Renal Physiol. (2002) [Pubmed]
  10. A phosphorylation-dependent export structure in ROMK (Kir 1.1) channel overrides an endoplasmic reticulum localization signal. Yoo, D., Fang, L., Mason, A., Kim, B.Y., Welling, P.A. J. Biol. Chem. (2005) [Pubmed]
  11. Dietary potassium restriction stimulates endocytosis of ROMK channel in rat cortical collecting duct. Chu, P.Y., Quigley, R., Babich, V., Huang, C.L. Am. J. Physiol. Renal Physiol. (2003) [Pubmed]
  12. Classification and rescue of ROMK mutations underlying hyperprostaglandin E syndrome/antenatal Bartter syndrome. Peters, M., Ermert, S., Jeck, N., Derst, C., Pechmann, U., Weber, S., Schlingmann, K.P., Seyberth, H.W., Waldegger, S., Konrad, M. Kidney Int. (2003) [Pubmed]
  13. An amino acid triplet in the NH2 terminus of rat ROMK1 determines interaction with SUR2B. Dong, K., Xu, J., Vanoye, C.G., Welch, R., MacGregor, G.G., Giebisch, G., Hebert, S.C. J. Biol. Chem. (2001) [Pubmed]
  14. Protein tyrosine kinase is expressed and regulates ROMK1 location in the cortical collecting duct. Lin, D.H., Sterling, H., Yang, B., Hebert, S.C., Giebisch, G., Wang, W.H. Am. J. Physiol. Renal Physiol. (2004) [Pubmed]
  15. Superoxide anions are involved in mediating the effect of low K intake on c-Src expression and renal K secretion in the cortical collecting duct. Babilonia, E., Wei, Y., Sterling, H., Kaminski, P., Wolin, M., Wang, W.H. J. Biol. Chem. (2005) [Pubmed]
  16. Regulation of K+ channel mRNA expression by stimulation of adenosine A2a-receptors in cultured rat microglia. Küst, B.M., Biber, K., van Calker, D., Gebicke-Haerter, P.J. Glia (1999) [Pubmed]
  17. Increased expression of the sodium transporter BSC-1 in spontaneously hypertensive rats. Sonalker, P.A., Tofovic, S.P., Jackson, E.K. J. Pharmacol. Exp. Ther. (2004) [Pubmed]
  18. Splicing of a retained intron within ROMK K+ channel RNA generates a novel set of isoforms in rat kidney. Beesley, A.H., Ortega, B., White, S.J. Am. J. Physiol. (1999) [Pubmed]
  19. Regulation of ROMK1 K+ channel activity involves phosphorylation processes. McNicholas, C.M., Wang, W., Ho, K., Hebert, S.C., Giebisch, G. Proc. Natl. Acad. Sci. U.S.A. (1994) [Pubmed]
  20. Regulation of potassium channel Kir 1.1 (ROMK) abundance in the thick ascending limb of Henle's loop. Ecelbarger, C.A., Kim, G.H., Knepper, M.A., Liu, J., Tate, M., Welling, P.A., Wade, J.B. J. Am. Soc. Nephrol. (2001) [Pubmed]
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