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Cloning of Xenopus laevis and Strongylocentrotus purpuratus Na‐K‐2Cl cotransporters
Author(s) -
Gag Kenneth B.,
England Roger,
Delpire Eric
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.936.3
Subject(s) - strongylocentrotus purpuratus , xenopus , sea urchin , cotransporter , biology , amino acid , echinoderm , threonine , cloning (programming) , biochemistry , peptide sequence , microbiology and biotechnology , phosphorylation , gene , chemistry , ecology , serine , organic chemistry , computer science , programming language , sodium
The Na‐K‐2Cl cotransporter (NKCC1) mediates the movement of ions and water across epithelia, and is important in the maintenance of cell volume. Our laboratory has used the amphibian ( Xenopus laevis ‐ African clawed frog) oocyte as a heterologous expression system for the study of mammalian NKCC1 function. The release of the echinoderm ( Strongylocentrotus purpuratus ‐ purple sea urchin) genome, which was lacking all NKCC1 regulatory elements (two SPAK binding domains, the PP1 binding domain, and the six conserved threonine residues) in its amino terminus, provided a unique opportunity for us to compare the molecular differences between echinoderm, amphibian, and mammalian cotransporters. In this study, we cloned NKCC1 from RNA extracted from the frog oocyte and sea urchin gonadal tissue. We found that the amino terminal domain of frog NKCC1, although smaller than mouse by 48 amino acid residues, has two SPAK binding domains and all six threonine residues previously identified as important to NKCC1 function. The sea urchin NKCC1 amino terminal domain, misidentified by the genome project, has only 149 residues compared to the 278 residues of mouse NKCC1, one SPAK binding domain and two of the six conserved threonine residues (sea urchin T87/T92 homologous to mouse T206/T211). The cloning of NKCC1 from these two new species allow us to further address the role of the N‐terminus in the regulation of the cotransporter.