The phorbol ester PMA and cyclic AMP activate different Cl(-) and HCO3(-) fluxes in C127 cells expressing CFTR.
In mouse mammary epithelial C127 cells expressing wild-type cystic fibrosis transmembrane conductance regulator (CFTR), chloride efflux, measured with the Cl(-)-sensitive dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ), was stimulated by activation of protein kinase A with cyclic AMP elevating agents forskolin plus 3-isobutyl-1-methyl-xanthine (IBMX) and, to a less extent, by activation of protein kinase C with the phorbol 12-myristate 13-acetate (PMA). Conversely, bicarbonate influx, determined by intracellular alkalinization of cells incubated with the pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluoresceintetraacetoxymethyl ester (BCECF-AM), was stimulated by cyclic AMP elevation, but not by PMA. Patch clamp analysis revealed that PMA activated a Cl(-) current with the typical biophysical characteristics of swelling-activated current and not of CFTR.
Zegarra-Moran
O
O
Lab. di Genetica Molecolare, Genova, Italy.
Porcelli
A M
AM
Rugolo
M
M
D000818:Animals; D017920:Antiporters / Q000378:metabolism; D001639:Bicarbonates / Q000378:metabolism*; D001692:Biological Transport; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D027963:Chloride-Bicarbonate Antiporters; D002712:Chlorides / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005456:Fluorescent Dyes; D051379:Mice; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000378:metabolism; D011806:Quinolinium Compounds; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D017920:Antiporters; D001639:Bicarbonates; D027963:Chloride-Bicarbonate Antiporters; D002712:Chlorides; D005456:Fluorescent Dyes; D011806:Quinolinium Compounds; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; C052335:6-methoxy-N-(3-sulfopropyl)quinolinium; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate