Electrodiffusional ATP movement through the cystic fibrosis transmembrane conductance regulator

HORACIO F. CANTIELLO, GEORGE R. JACKSON, JR., CLAUDIO F. GROSMAN, ADRIANA G. PRAT, STEVEN C. BORKAN, YIHAN WANG, IGNACIO L. REISIN,CATHERINE R. O’RIORDAN AND DENNIS A. AUSIELLO

AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY

Año: 1998 p. 799 - 809

0363-6143

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 Cl2 and ATP. Similar to previously reported data for in vivo ATP currents of CFTRexpressing cells, the reconstituted channels displayed competition between Cl2 and ATP and had multiple conductance states in the presence of Cl2 and ATP. Purified CFTRmediated 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 CFTRmediated electrodiffusional ATP movement may thus be arelevant component of the pleiotropic cystic fibrosis phenotype.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 Cl2 and ATP. Similar to previously reported data for in vivo ATP currents of CFTRexpressing cells, the reconstituted channels displayed competition between Cl2 and ATP and had multiple conductance states in the presence of Cl2 and ATP. Purified CFTRmediated 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 CFTRmediated electrodiffusional ATP movement may thus be arelevant component of the pleiotropic cystic fibrosis phenotype.