TCDB is operated by the Saier Lab Bioinformatics Group
Transporter Information:
Name: potassium inwardly-rectifying channel, subfamily J, member 1
Symbol: KCNJ1
TC: 1.A.2.1.1
Locations: 11q24
Aliases: ROMK1, Kir1.1
Swiss-Prot: P48048
Accession Number: NM_000220
PubMed (7680431): Ho K, Nichols CG, Lederer WJ, Lytton J, Vassilev PM, Kanazirska MV, HebertSC. Cloning and expression of an inwardly rectifying ATP-regulated potassiumchannel.Nature. 1993 Mar 4;362(6415):31-8. PMID: 7680431 [PubMed - indexed for MEDLINE]

A complementary DNA encoding an ATP-regulated potassium channel has been isolated by expression cloning from rat kidney. The predicted 45K protein, which features two potential membrane-spanning helices and a proposed ATP-binding domain, represents a major departure from the basic structural design characteristic of voltage-gated and second messenger-gated ion channels. But the presence of an H5 region, which is likely to form the ion conduction pathway, indicates that the protein may share a common origin with voltage-gated potassium channel proteins.

PubMed (8190102): Yano H, Philipson LH, Kugler JL, Tokuyama Y, Davis EM, Le Beau MM, NelsonDJ, Bell GI, Takeda J. Alternative splicing of human inwardly rectifying K+ channel ROMK1 mRNA.Mol Pharmacol. 1994 May;45(5):854-60. PMID: 8190102 [PubMed - indexed for MEDLINE]

Recent studies have identified a new family of inwardly rectifying K+ channels, members of which are known by the acronyms ROMK1, IRK1, and GIRK1. We have isolated cDNAs encoding the human homologue of ROMK1 from an adult kidney cDNA library. The sequences of the human kidney ROMK1 cDNA clones indicated that they were derived from at least two types of mRNAs, human ROMK1A and human ROMK1B, differing in sequence at their 5' ends. The isolation of the human ROMK1 gene, localized to chromosome band 11q24 by fluorescence in situ hybridization, indicated that the different ROMK1 transcripts were generated by alternative splicing. Human ROMK1A mRNA was predicted to encode a protein of 389 amino acids, having 93% identity with the 391-residue rat ROMK1 protein, and expression studies in Xenopus oocytes indicated that it encoded a Ba(2+)-sensitive inwardly rectifying K+ channel with properties similar to those reported for cloned rat ROMK1. Human ROMK1B mRNA was predicted to encode a protein of 372 amino acids whose sequence was truncated at the amino terminus but otherwise identical to that of the human ROMK1A protein. Translation of human ROMK1B mRNA was predicted to initiate at a codon corresponding to Met-18 of human ROMK1A mRNA. Reverse transcriptase-polymerase chain reaction amplification of human kidney mRNA revealed human ROMK1A and -B transcripts as well as a third type of transcript, human ROMK1C mRNA, which was predicted to encode a protein identical to human ROMK1B. Human ROMK1A, -B, and -C transcripts were identified in kidney, whereas only human ROMK1A mRNA could be detected in pancreatic islets and other tissues in which human ROMK1 was expressed at low levels. Thus, tissue-specific alternative splicing of human ROMK1 mRNA may result in the expression of a family of ROMK1 proteins.

>sp|P48048|IRK1_HUMAN ATP-sensitive inward rectifier potassium channel 1 OS=Homo sapiens GN=KCNJ1 PE=1 SV=1