Electrodiffusional ATP movement through the cystic fibrosis transmembrane conductance regulator.
Expression of the cystic fibrosis transmembrane conductance regulator (CFTR), and of at least one other member of the ATP-binding cassette family of transport proteins, P-glycoprotein, is associated with the electrodiffusional movement of the nucleotide ATP. Evidence directly implicating CFTR expression with ATP channel activity, however, is still missing. Here it is reported that reconstitution into a lipid bilayer of highly purified CFTR of human epithelial origin enables the permeation of both Cl- and ATP. Similar to previously reported data for in vivo ATP current of CFTR-expressing cells, the reconstituted channels displayed competition between Cl- and ATP and had multiple conductance states in the presence of Cl- and ATP. Purified CFTR-mediated ATP currents were activated by protein kinase A and ATP (1 mM) from the "intracellular" side of the molecule and were inhibited by diphenylamine-2-carboxylate, glibenclamide, and anti-CFTR antibodies. The absence of CFTR-mediated electrodiffusional ATP movement may thus be a relevant component of the pleiotropic cystic fibrosis phenotype.
Cantiello
H F
HF
Renal Unit, Massachusetts General Hospital East, Charlestown, Massachusetts 02129, USA.
Jackson
G R
GR
Grosman
C F
CF
Prat
A G
AG
Borkan
S C
SC
Wang
Y
Y
Reisin
I L
IL
O'Riordan
C R
CR
Ausiello
D A
DA
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002121:Calcium Channel Blockers / Q000378:metabolism; D002460:Cell Line; D018118:Chloride Channels / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D004058:Diffusion; D004553:Electric Conductivity; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D008958:Models, Molecular; D011994:Recombinant Proteins / Q000378:metabolism; D018411:Spodoptera; D062367:ortho-Aminobenzoates / Q000378:metabolism
C505032:CFTR protein, human; D002121:Calcium Channel Blockers; D018118:Chloride Channels; D002712:Chlorides; D008051:Lipid Bilayers; D011994:Recombinant Proteins; D062367:ortho-Aminobenzoates; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000255:Adenosine Triphosphate; C001209:fenamic acid; D017868:Cyclic AMP-Dependent Protein Kinases; D008274:Magnesium