NDPK-A (but not NDPK-B) and AMPK alpha1 (but not AMPK alpha2) bind the cystic fibrosis transmembrane conductance regulator in epithelial cell membranes.
Cystic fibrosis (CF) results from mutations within the cystic fibrosis transmembrane-conductance regulator (CFTR) protein. The AMP-activated protein kinase (AMPK) is a heterotrimer composed of different isoforms of the alphabetagamma subunits, where the alpha1 catalytic subunit binds CFTR. Nucleoside diphosphate kinase (NDPK, NM23/awd) converts nucleoside diphosphates to nucleoside triphosphates but also acts as a protein kinase. We recently showed that AMPK alpha1 binds NDPK-A in lung epithelial cytosol. Here we report that in the plasma membrane of human airway epithelial cells, NDPK-A and AMPK alpha1 associate with the plasma membrane via CFTR. We show that the regulatory domain of CFTR binds NDPK-A whereas AMPK gamma1 or gamma2 bind the first nucleotide binding domain (NBD1) and AMPK alpha1 binds the second (NBD2) of CFTR. We also show that NDPK-A specifically binds AMPK alpha1 and AMPK gamma2 subunits, thereby specifying the isozyme of AMPK heterotrimer that associates with CFTR at the membrane. Thus, the combined data provide novel insight into the subunit composition of the epithelial CFTR/AMPK/NDPK complex, such that: CFTR interacts specifically with AMPK alpha1, gamma2 and NDPK-A and not NDPK-B or AMPK gamma1.
Crawford
Russell M
RM
Department of Maternal and Child Health Sciences, University of Dundee, Ninewells Hospital, Dundee, DD1 9SY, UK.
Treharne
Kate J
KJ
Best
O Giles
OG
Riemen
Claudia E
CE
Muimo
Richmond
R
Gruenert
Dieter C
DC
Arnaud-Dabernat
Sandrine
S
Daniel
Jean-Yves
JY
Mehta
Anil
A
D055372:AMP-Activated Protein Kinases; D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000166:cytology; D051379:Mice; D008954:Models, Biological; D009097:Multienzyme Complexes / Q000378:metabolism*; D009701:Nucleoside-Diphosphate Kinase / Q000172:deficiency / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*
D009097:Multienzyme Complexes; D009711:Nucleotides; C526224:Prkag1 protein, mouse; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C526181:PRKAA2 protein, human; C526222:PRKAG1 protein, human; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C526180:PRKAA1 protein, human; D009701:Nucleoside-Diphosphate Kinase