title: Defective formation of PKA/CnA-dependent annexin 2-S100A10/CFTR complex in DeltaF508 cystic fibrosis cells.
abstract: Cystic fibrosis (CF) is characterised by impaired epithelial ion transport and is caused by mutations in the cystic fibrosis conductance regulator protein (CFTR), a cAMP/PKA and ATP-regulated chloride channel. We recently demonstrated a cAMP/PKA/calcineurin (CnA)-driven association between annexin 2 (anx 2), its cognate partner -S100A10 and cell surface CFTR. The complex is required for CFTR and outwardly rectifying chloride channel function in epithelia. Since the cAMP/PKA-induced Cl(-) current is absent in CF epithelia, we hypothesized that the anx 2-S100A10/CFTR complex may be defective in CFBE41o cells expressing the commonest F508del-CFTR (DeltaF-CFTR) mutation. Here, we demonstrate that, despite the presence of cell surface DeltaF-CFTR, cAMP/PKA fails to induce anx 2-S100A10/CFTR complex formation in CFBE41o- cells homozygous for F508del-CFTR. Mechanistically, PKA-dependent serine phosphorylation of CnA, CnA-anx 2 complex formation and CnA-dependent dephosphorylation of anx 2 are all defective in CFBE41o- cells. Immunohistochemical analysis confirms an abnormal cellular distribution of anx 2 in human and CF mouse epithelia. Thus, we demonstrate that cAMP/PKA/CnA signaling pathway is defective in CF cells and suggest that loss of anx 2-S100A10/CFTR complex formation may contribute to defective cAMP/PKA-dependent CFTR channel function.
authors.affiliation: Academic Unit of Child Health, The University of Sheffield, Sheffield Children's, Hospital, Stephenson Wing, Sheffield, S10 2TH, UK.
authors.forename: Lee Anthony
authors.initials: LA
authors.lastname: Borthwick
authors.forename: Claudia
authors.initials: C
authors.lastname: Riemen
authors.forename: Catharine
authors.initials: C
authors.lastname: Goddard
authors.forename: William H
authors.initials: WH
authors.lastname: Colledge
authors.forename: Anil
authors.initials: A
authors.lastname: Mehta
authors.forename: Volker
authors.initials: V
authors.lastname: Gerke
authors.forename: Richmond
authors.initials: R
authors.lastname: Muimo
mesh_terms: D000328:Adult; D000818:Animals; D017306:Annexin A2 / Q000032:analysis / Q000378:metabolism*; D019703:Calcineurin / Q000032:analysis / Q000378:metabolism*; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D009154:Mutation; D020545:Respiratory Mucosa / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D009418:S100 Proteins / Q000032:analysis / Q000378:metabolism*; D000099248:S100 Calcium Binding Protein A10
chemical_list: D017306:Annexin A2; D019703:Calcineurin; D017868:Cyclic AMP-Dependent Protein Kinases; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D009418:S100 Proteins; D000099248:S100 Calcium Binding Protein A10