Fachbereich Veterinärmedizin



    Cellular Distribution and Subcellular Localization of mCLCA1/2 in Murine Gastrointestinal Epithelia (2010)

    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Roussa, Eleni
    Wittschen, Petra
    Wolff, Natascha A
    Torchalski, Blazej
    Gruber, Achim D
    Thévenod, Frank
    The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society; 58(7) — S. 653–668
    ISSN: 0022-1554
    DOI: 10.1369/jhc.2010.955211
    Pubmed: 20385786
    Institut für Tierpathologie

    Robert-von-Ostertag-Str. 15
    Gebäude 12
    14163 Berlin
    Tel.+49 30 838 62450 Fax.+49 30 838 62522

    Abstract / Zusammenfassung

    mCLCA1/2 are members of the CLCA protein family that are widely expressed in secretory epithelia, but their putative physiological role still awaits elucidation. mCLCA1/2 have 95% amino acid identity, but currently no specific antibody is available. We have generated a rabbit polyclonal antibody (pAb849) against aa 424-443 of mCLCA1/2. In HEK293 cells transfected with mCLCA1; pAb849 detected two specific protein bands at approximately 125 kDa and 90 kDa, representing full-length precursor and N-terminal cleavage product, respectively. pAb849 also immunoprecipitated mCLCA1 and labeled the protein by immunostaining. But pAb849 crossreacted with mCLCA3/4/6 despite < or =80% amino acid identity of the antigenic epitope. We therefore investigated the cellular localization of mCLCA1/2 in epithelial tissues, which do not express mCLCA3/4/6 (salivary glands, pancreas, kidney) or express mCLCA3/6 with known localization (mucus cells of stomach and small intestine; villi of small intestine). mCLCA1/2 mRNA and protein expression were found in both parotid and submandibular gland, and immunohistochemistry revealed labeling in parotid acinar cells, in the luminal membrane of parotid duct cells, and in the duct cells of submandibular gland. In exocrine pancreas, mCLCA1/2 expression was restricted to acinar zymogen granule membranes, as assessed by immunoblotting, immunohistochemistry, and preembedding immunoperoxidase and immunogold electron microscopy. Moreover, mCLCA1/2 immunolabeling was present in luminal membranes of gastric parietal cells and small intestinal crypt enterocytes, whereas in the kidney, mCLCA1/2 protein was localized to proximal and distal tubules. The apical membrane localization and overall distribution pattern of mCLCA1/2 favor a transmembrane protein implicated in transepithelial ion transport and protein secretion.