Cloning, characterization, and gene organization of K-Cl cotransporter from pig and human kidney and C. elegans.
We isolated and characterized the cDNAs for the human, pig, and Caenorhabditis elegans K-Cl cotransporters. The pig and human homologs are 94% identical and contain 1,085 and 1,086 amino acids, respectively. The deduced protein of the C. elegans K-Cl cotransporter clone (CE-KCC1) contains 1,003 amino acids. The mammalian K-Cl cotransporters share approximately 45% similarity with CE-KCC1. Hydropathy analyses of the three clones indicate typical KCC topology patterns with 12 transmembrane segments, large extracellular loops between transmembrane domains 5 and 6 (unique to KCC), and large COOH-terminal domains. Human KCC1 is widely expressed among various tissues. This KCC1 gene spans 23 kb and is organized in 24 exons, whereas the CE-KCC1 gene spans 3.5 kb and contains 10 exons. Transiently and stably transfected human embryonic kidney cells (HEK-293) expressing the human, pig, and C. elegans K-Cl cotransporter fulfilled two (pig) or five (human and C. elegans) criteria for increased expression of the K-Cl cotransporter. The criteria employed were basal K-Cl cotransport; stimulation of cotransport by swelling, N-ethylmaleimide, staurosporine, and reduced cell Mg concentration; and secondary stimulation of Na-K-Cl cotransport.
Renal Division, Department of Medicine, State University of New York-Health Science Center, Syracuse, New York 13210, USA.
E J
EJ
Holtzman
S
S
Kumar
C A
CA
Faaland
F
F
Warner
P J
PJ
Logue
S J
SJ
Erickson
G
G
Ricken
J
J
Waldman
S
S
Kumar
P B
PB
Dunham
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D005091:Exons; D015723:Gene Library; D006801:Humans; D007438:Introns; D007668:Kidney / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011188:Potassium / Q000378:metabolism*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013552:Swine; D027981:Symporters; D014162:Transfection; D000096922:K Cl- Cotransporters
D002352:Carrier Proteins; D017931:DNA Primers; D011188:Potassium; D011994:Recombinant Proteins; D027981:Symporters; D000096922:K Cl- Cotransporters