Kir1.1 channels

Channel name Kir1.1
Description Inwardly rectifying potassium channel Kir1.1 subunit
Other names Kir1.1, ROMK, ROMK1
Molecular information Human (KCNJ1): 391aa, Locus ID: 3758, GenBank: U12541, NM_000220, PMID: 7929082,1 chr. 11q24
Rat (Kcnj1): 391aa, Locus ID: 24521, GenBank: X72341, NM_017023, PMID: 7680431,2 chr. 8q21
Mouse (Kcnj1): 372aa, Locus ID: 56379, GenBank: AF012834 (see “Comments”), NM_019659, PMID: 7611454,3 89801344,4 chr. 9A
Associated subunits Na+/H+ exchange regulatory factor 2 (NHERF2) (not required for function5)
Functional assays Voltage-clamp
Current Inwardly rectifying K+ current
Conductance 47pS (285 mM K+), 40pS (140 mM K+)
Ion selectivity K+
Activation Not established
Inactivation Intracellular acidification
Activators None
Gating inhibitors None
Blockers Nonselective: Ba2+, Cs+
Radioligands None
Channel distribution Kidney (apical membranes in cortex and outer medulla), RT-PCR shows transcripts in skeletal muscle, pancreas, spleen, brain, heart, and liver
Physiological functions K+ secretion (Kir1.1a, Kir1.1c, distal renal tubule), K+ recycling (Kir1.1b, thick ascending limb of loop of Henle)
Mutations and pathophysiology Bartter's syndrome6
Pharmacological significance Not established
Comments Six splice variants exist, denoted as Kir1.1a, Kir1.1b, Kir1.1c, Kir1.1d, Kir1.1e, and Kir1.1f
  • aa, amino acids; chr., chromosome; RT-PCR, reverse transcriptase-polymerase chain reaction.

  • 1. Shuck ME, Bock JH, Benjamin CW, Tsai TD, Lee KS, Slightom JL, and Bienkowski MJ (1994) Cloning and characterization of multiple forms of the human kidney ROM-K potassium channel. J Biol Chem 269:24261-24270

  • 2. Ho K, Nichols CG, Lederer WJ, Lytton J, Vassilev PM, Kanazirska MV, and Hebert SC (1993) Cloning and expression of an inwardly rectifying ATP-regulated potassium channel. Nature (Lond) 362:31-38

  • 3. Boim MA, Ho K, Shuck ME, Bienkowski MJ, Block JH, Slightom JL, Yang Y, Brenner BM, and Hebert SC (1995) ROMK inwardly rectifying ATP-sensitive K+ channel. II. Cloning and distribution of alternative forms. Am J Physiol 268:F1132-F1140

  • 4. Kondo C, Isomoto S, Matsumoto S, Yamada M, Horio Y, Yamashita S, Takemura-Kameda K, Matsuzawa Y, and Kurachi Y. (1996) Cloning and functional expression of a novel isoform of ROMK inwardly rectifying ATP-dependent K+ channel, ROMK6 (Kir1.1f). FEBS Lett 399:122-126

  • 5. Yoo D, Flagg TP, Olsen O, Raghuram V, Foskett JK, and Welling PA (2004) Assembly and trafficking of a multiprotein ROMK (Kir 1.1) channel complex by PDZ interactions. J Biol Chem 279:6863-6873

  • 6. Schwalbe RA, Bianchi L, Accili EA, and Brown AM (1998) Functional consequences of ROMK mutants linked to antenatal Bartter's syndrome and implications for treatment. Hum Mol Genet 7:975-980