CFTR is activated through stimulation of purinergic P2Y2 receptors.
It has been reported that the cystic fibrosis transmembrane conductance regulator (CFTR) can be activated through cAMP- and protein kinase A-independent pathways involving GTP-binding proteins and an unknown kinase. In this study, we further examined how G protein-coupled pathways regulate CFTR. We demonstrate that stimulation of purinergic P2Y(2) receptors in CFTR-expressing oocytes and in airway epithelial cells activates CFTR Cl(-) currents. Activation of CFTR Cl(-) currents via P2Y(2) was inhibited by CFTR(inh)-172 and was independent of intracellular Ca(2+), protein kinase C, or calmodulin-dependent kinase (CAMK). However, activation of CFTR was suppressed by inhibition of phospholipase C and by the nonselective protein kinase inhibitor staurosporine. Activation of CFTR through P2Y(2) receptors was enhanced when G(i) proteins were inhibited by pertussis toxin. Inhibition of protein kinase A and of protein kinases downstream of P2Y(2) receptors such as mitogen-activated protein kinases, tyrosine kinase, or c-src kinase did not interfere with activation of CFTR. The present results demonstrate an antagonistic regulation of CFTR by P2Y(2) receptors: CFTR is inhibited by stimulation of G(i) proteins and is activated by stimulation of G(q/11)/PLC and an unknown downstream protein kinase.
Faria
Diana
D
Department of Physiology, University of Regensburg, Regensburg, Germany.
Schreiber
Rainer
R
Kunzelmann
Karl
K
D000818:Animals; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000502:physiology*; D054769:G-Protein-Coupled Receptor Kinase 2 / Q000502:physiology; D006801:Humans; D009865:Oocytes / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D058473:Receptors, Purinergic P2Y2; D010738:Type C Phospholipases / Q000502:physiology; D014982:Xenopus laevis
C546385:P2RY2 protein, human; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C496567:GRK2 protein, human; D054769:G-Protein-Coupled Receptor Kinase 2; D010738:Type C Phospholipases