POSSIBLE REGULATION OF CFTR-CHLORIDE CHANNELS BY MEMBRANE-BOUND PHOSPHATASES IN PANCREATIC DUCT CELLS

We have studied CFTR-Cl- channels in non-CF CAPAN-1 and in CFTR-transf ected CFPAC-PLJ-CFTR-6 epithelial cells from human pancreas. Theophyll ine and IBMX induced the opening of cell-attached CFTR-Cl- channels. T heophylline, IBMX and the alkaline phosphatase (AP) inhibitor levamiso le enhanced the activity of excised channels and reduced by 70-75% the apical membrane-associated APs activity. Okadaic acid had no effect o n APs and channel activities. A polyclonal anti-alkaline phosphatase a ntibody (which detected apical APs) reduced APs activity and activated quiescent excised chloride channels. These results suggest that CFTR channels may be regulated by membrane-bound phosphatases.