Cloning, characterization and gene organization of k-cl
cotransporter from pig and human kidney and C. elegans.
Holtzman, Eli J., Sumit Kumar, Carol A. Faaland, Fern Warner, Paul J.
Logue, Sara J. Erickson, Gesa Ricken, Jeremy Waldman, Shiv Kumar and
Philip B. Dunham.
1Renal Division, Department of Medicine, 3Department of
Biochemistry and Molecular Biology, SUNY-Health Science Center,
Syracuse, NY, and 2Department of Biology, Syracuse University,
Syracuse, NY.
APStracts 5:0119F, 1998.
We isolated and characterized the cDNAs for the human, pig, and C.
elegans K-Cl cotransporters. The pig and human homologues are 94%
identical and contain 1085 and 1086 amino acids, respectively The
deduced protein of the C. elegans clone (CE-KCC1) contains 1003 amino
acids. The mammalian K-Cl cotransporters share 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 C-terminal domains. Human KCC1 is widely expressed among
various tissues. This KCC1 gene spans 23 kb and is organized in 24
exons, while the CE-KCC1 gene spans 3.5 kb and contains 10 exons.
Transiently and stably transfected HEK-293 cells 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 by reduced cell [Mg], and
secondary stimulation of Na-K-Cl cotransport.
Received 19 March 1998; accepted in final form 26 June 1998.
APS Manuscript Number F67-8.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 30 July 1998