title: cAMP stimulates protein kinase C activity in cultured renal LLC-PK1 cells.
abstract: Exposure of intact LLC-PK1 cells to the phorbol ester 4-phorbol 12-myristate 13-acetate (PMA) increases basal, arginine vasopressin-stimulated, and forskolin-stimulated adenylate cyclase activity in LLC-PK1 membranes. This observation suggests that protein kinase C can increase adenosine 3',5'-cyclic monophosphate (cAMP) in LLC-PK1 cells. To determine whether cAMP regulates protein kinase C activity in LLC-PK1 cells, intact cells were exposed to either forskolin or to soluble cAMP analogues. Acute (5 and 30 min) exposure to either forskolin or cAMP analogues increases protein kinase C activity as observed by two different methods for measuring protein kinase C. Acute exposure to PMA translocates protein kinase C from a soluble to a particulate cell fraction, whereas acute exposure to cAMP increases both soluble and particulate forms of protein kinase C. Longer exposure (18 h) to PMA results in a loss of protein kinase C activity, whereas 18-h exposure to cAMP results in a further increase in protein kinase C activity. The effect of cAMP but not of PMA to stimulate protein kinase C activity can be attenuated by the pro-R diastereoisomer of adenosine 3',5'-cyclic phosphorothioate, suggesting a protein kinase A-mediated effect. These results suggest the presence of a monodirectional mode of signal transduction system interaction in LLC-PK1 cells in which protein kinase C and protein kinase A can potentiate each other.
authors.affiliation: Department of Medicine, Denver Veterans Affairs Medical Center, Colorado.
authors.forename: R J
authors.initials: RJ
authors.lastname: Anderson
authors.forename: R
authors.initials: R
authors.lastname: Breckon
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D001127:Arginine Vasopressin / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology*; D007668:Kidney / Q000201:enzymology*; D011493:Protein Kinase C / Q000378:metabolism*; D047428:Protein Kinase Inhibitors; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D047428:Protein Kinase Inhibitors; D013873:Thionucleotides; D001127:Arginine Vasopressin; D005576:Colforsin; C016957:adenosine-3',5'-cyclic phosphorothioate; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D000242:Cyclic AMP; D011493:Protein Kinase C; D000262:Adenylyl Cyclases; D013755:Tetradecanoylphorbol Acetate