title: Endocytosis is regulated by protein kinase A, but not protein kinase C in a secretory epithelial cell line.
abstract: Endocytosis in the chloride secreting epithelial cell line T84 was monitored by uptake of the fluid-phase markers FITC-dextran and horseradish peroxidase (HRP). Uptake of marker was inhibited by incubation of cells at 4 degrees C, consistent with an endocytic uptake. Although activation of the cAMP-dependent second messenger pathway has been shown to stimulate exocytosis in this cell line, it caused a 63% reduction in endocytosis as measured by uptake of fluid-phase markers. In contrast, the presence of the protein kinase C activator phorbol-myristate acetate (PMA) caused no significant reduction in the level of endocytosis compared to control, nor did it reverse the inhibitory effect of PKA activation. The data thus suggest that endocytosis in T84 cells is regulated through activation of protein kinase A, but not through activation of protein kinase C.
authors.affiliation: Department of Physiology & Biophysics, University of Alabama, Birmingham 35294.
authors.forename: N A
authors.initials: NA
authors.lastname: Bradbury
authors.forename: R J
authors.initials: RJ
authors.lastname: Bridges
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line; D002712:Chlorides / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D003911:Dextrans; D004075:Diglycerides / Q000494:pharmacology; D004705:Endocytosis; D004848:Epithelium; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives; D006706:Homeostasis; D006735:Horseradish Peroxidase / Q000378:metabolism; D007700:Kinetics; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D015290:Second Messenger Systems; D019311:Staurosporine; D013696:Temperature; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D002712:Chlorides; D003911:Dextrans; D004075:Diglycerides; C015219:fluorescein isothiocyanate dextran; D005576:Colforsin; D000242:Cyclic AMP; D006735:Horseradish Peroxidase; D011494:Protein Kinases; D011493:Protein Kinase C; D019311:Staurosporine; D016650:Fluorescein-5-isothiocyanate; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; C013965:diolein