title: Annexin V is directly involved in cystic fibrosis transmembrane conductance regulator's chloride channel function.
abstract: The cystic fibrosis transmembrane conductance regulator (CFTR) functions as a cAMP-activated chloride channel, which is regulated by protein-protein interactions. The extent to which CFTR is regulated by these interactions remains unknown. Annexin V is overexpressed in cystic fibrosis (CF), and given the functional properties of annexin V and CFTR we considered whether they are associated and if so whether this has implications for CFTR function. Using co-immunoprecipitation and overlay experiments, we show that annexin V is associated with nucleotide-binding domain 1 (NBD1) of CFTR. Surface plasmon resonance (SPR) indicated different KD values in the absence and presence of both calcium and ATP, suggesting that this interaction is calcium- and ATP-dependent. Using an siRNA approach and overexpression, we showed that CFTR chloride channel function and its localization in the cell membranes were dependent on annexin V expression. We concluded that annexin V is necessary for normal CFTR chloride channel activity. Furthermore, we show that CFTR and annexin V are partially co-distributed in normal epithelial cells in human bronchi. In conclusion, we show for the first time that annexin V is associated with CFTR and is involved in its function.
authors.affiliation: INSERM, Unité 613, 46 rue Félix le Dantec, BP62025, 29220 Brest, France. pascal.trouve@univ-brest.fr
authors.forename: Pascal
authors.initials: P
authors.lastname: Trouvé
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Le Drévo
authors.forename: Mathieu
authors.initials: M
authors.lastname: Kerbiriou
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Friocourt
authors.forename: Yann
authors.initials: Y
authors.lastname: Fichou
authors.forename: Danièle
authors.initials: D
authors.lastname: Gillet
authors.forename: Claude
authors.initials: C
authors.lastname: Férec
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D017304:Annexin A5 / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000242:Cyclic AMP / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000737:chemistry / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D020349:Surface Plasmon Resonance; D014132:Trachea / Q000737:chemistry / Q000378:metabolism*
chemical_list: D017304:Annexin A5; C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000255:Adenosine Triphosphate; D000242:Cyclic AMP; D002118:Calcium