Fachbereich Veterinärmedizin



    Molecular Cloning and Transmembrane Structure of hCLCA2 from Human Lung, Trachea, and Mammary Gland (1999)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Gruber, A D (WE 12)
    Schreur, K D
    Ji, H L
    Fuller, C M
    Pauli, B U
    The American journal of physiology; 276(6 Pt 1) — S. C1261–C1270
    ISSN: 0002-9513
    Pubmed: 10362588
    Institut für Tierpathologie

    Robert-von-Ostertag-Str. 15
    Gebäude 12
    14163 Berlin
    +49 30 838 62450

    Abstract / Zusammenfassung

    The CLCA family of Ca2+-activated Cl- channels has recently been discovered, with an increasing number of closely related members isolated from different species. Here we report the cloning of the second human homolog, hCLCA2, from a human lung cDNA library. Northern blot and RT-PCR analyses revealed additional expression in trachea and mammary gland. A primary translation product of 120 kDa was cleaved into two cell surface-associated glycoproteins of 86 and 34 kDa in transfected HEK-293 cells. hCLCA2 is the first CLCA homolog for which the transmembrane structure has been systematically studied. Glycosylation site scanning and protease protection assays revealed five transmembrane domains with a large, cysteine-rich, amino-terminal extracellular domain. Whole cell patch-clamp recordings of hCLCA2-transfected HEK-293 cells detected a slightly outwardly rectifying anion conductance that was increased in the presence of the Ca2+ ionophore ionomycin and inhibited by DIDS, dithiothreitol, niflumic acid, and tamoxifen. Expression in human trachea and lung suggests that hCLCA2 may play a role in the complex pathogenesis of cystic fibrosis.