Type II protein kinase A regulates CFTR in airway, pancreatic, and intestinal cells

• Published in: American Journal of Physiology: Cell Physiology 1998-03, Vol.274 (3), p.C819
• Main Authors: Steagall, Wendy K, Kelley, Thomas J, Marsick, Rebecca J, Drumm, Mitchell L
• Format: Article
• Language: English
• ISSN: 1522-1563
• DOI: 10.1152/ajpcell.1998.274.3.C819

The type of protein kinase A (PKA) responsible for cystic fibrosis transmembrane conductance regulator (CFTR) activation was determined with adenosine 3',5'-cyclic monophosphate analogs capable of selectively activating type I or type II PKA. The type II-selective pair stimulated chloride efflux in airway, pancreatic, and colonic epithelial cells; the type I-selective pair only stimulated a calcium-dependent efflux in airway cells. The type II-selective analogs activated larger increases in CFTR-mediated current than did the type I-selective analogs. Measurement of soluble PKA activity demonstrated similar levels stimulated by type I- and type II-selective analogs, creating an apparent paradox regarding PKA activity and current generated. Also, addition of forskolin after the type I-selective analogs resulted in an increase in current; little increase was seen after the type II-selective analogs. Measurement of insoluble PKA activity stimulated by the analogs resolved this paradox. Type II-selective analogs stimulated three times as much insoluble PKA activity as the type I-selective pair, indicating that differential activation of PKA in cellular compartments is important in CFTR regulation.