title: Localization of cystic fibrosis transmembrane conductance regulator signaling complexes in human salivary gland striated duct cells.
abstract: The cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-dependent protein kinase (PKA)-regulated Cl(-) channel, crucial for epithelial cell regulation of salt and water transport. Previous studies showed that ezrin, an actin binding and A-kinase anchoring protein (AKAP), facilitates association of PKA with CFTR. We used immunohistochemistry and immunogold transmission electron microscopy to localize CFTR, ezrin, and PKA type II regulatory (RII) and catalytic (C) subunits in striated duct cells of human parotid and submandibular glands. Immunohistochemistry localized the four proteins mainly to the apical membrane and the apical cytoplasm of striated duct cells. In acinar cells, ezrin localized to the luminal membrane, and PKA RII subunits were present in secretory granules, as previously described. Immunogold labeling showed that CFTR and PKA RII and C subunits were localized to the luminal membrane and associated with apical granules and vesicles of striated duct cells. Ezrin was present along the luminal membrane, on microvilli and along the junctional complexes between cells. Double labeling showed specific protein associations with apical granules and vesicles and along the luminal membrane. Ezrin, CFTR, and PKA RII and C subunits are co-localized in striated duct cells, suggesting the presence of signaling complexes that serve to regulate CFTR activity.
authors.affiliation: University of Connecticut School of Dental Medicine, Farmington, CT, USA.
authors.forename: Vina Z
authors.initials: VZ
authors.lastname: Zinn
authors.forename: Aditi
authors.initials: A
authors.lastname: Khatri
authors.forename: Maija I
authors.initials: MI
authors.lastname: Mednieks
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Hand
mesh_terms: D054758:A Kinase Anchor Proteins / Q000032:analysis; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits / Q000032:analysis; D054746:Cyclic AMP-Dependent Protein Kinase Type II / Q000032:analysis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000032:analysis*; D003593:Cytoplasm / Q000737:chemistry / Q000648:ultrastructure; D003598:Cytoskeletal Proteins / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000737:chemistry / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008871:Microvilli / Q000737:chemistry / Q000648:ultrastructure; D010306:Parotid Gland / Q000737:chemistry* / Q000166:cytology; D018987:Salivary Ducts / Q000737:chemistry* / Q000166:cytology; D022142:Secretory Vesicles / Q000737:chemistry / Q000648:ultrastructure; D013363:Submandibular Gland / Q000737:chemistry* / Q000166:cytology; D014617:Vacuoles / Q000737:chemistry / Q000648:ultrastructure; D000099149:Ezrin
chemical_list: D054758:A Kinase Anchor Proteins; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003598:Cytoskeletal Proteins; D000099149:Ezrin; C505032:CFTR protein, human
keywords: immunohistochemistry; parotid gland; protein kinase A; submandibular gland; transmission electron microscopy