title: Inhibition of the H+/peptide cotransporter in the human intestinal cell line Caco-2 by cyclic AMP.
abstract: Treatment of Caco-2 cells with cholera toxin inhibits the activity of the H+/peptide cotransporter. The effect of cholera toxin is mimicked by E. coli heat-labile enterotoxin, forskolin and isobutylmethylxanthine and is associated with an increase in cAMP levels in the cells. The inhibition is due to a decrease in the maximal velocity of the transport system. Inhibitors of protein kinase A and protein kinase C block the effect of cholera toxin. Interestingly, the H+/peptide cotransporter in Caco-2 cells does not possess any putative site for phosphorylation by protein kinase A but does possess sites for phosphorylation by protein kinase C. It appears that the cAMP-dependent inhibition of the H+/peptide cotransporter in Caco-2 cells is mediated through activation of protein kinase C.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100, USA.
authors.forename: U
authors.initials: U
authors.lastname: Muller
authors.forename: M
authors.initials: M
authors.lastname: Brandsch
authors.forename: P D
authors.initials: PD
authors.lastname: Prasad
authors.forename: Y J
authors.initials: YJ
authors.lastname: Fei
authors.forename: V
authors.initials: V
authors.lastname: Ganapathy
authors.forename: F H
authors.initials: FH
authors.lastname: Leibach
mesh_terms: D001483:Base Sequence; D018938:Caco-2 Cells; D015820:Cadherins; D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D017931:DNA Primers / Q000737:chemistry; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000166:cytology; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C490584:CDH17 protein, human; D015820:Cadherins; D002352:Carrier Proteins; D017931:DNA Primers; D004791:Enzyme Inhibitors; D026901:Membrane Transport Proteins; C067802:intestinal peptide-proton cotransporter; D002772:Cholera Toxin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D019204:GTP-Binding Proteins