Co-requirement of cyclic AMP- and calcium-dependent protein kinases for transcriptional activation of cholecystokinin gene by protein hydrolysates.
Little is known about the mechanisms by which protein-derived nutrients regulate hormone gene expression in the intestine. We have previously reported that protein hydrolysates (i.e. peptones), which are representative of the protein fraction in the lumen, increased cholecystokinin (CCK) gene transcription in the STC-1 enteroendocrine cell line. In the present work, we examined the intracellular events evoked by peptones to stimulate CCK gene transcription. In STC-1 cells, peptones stimulated cyclic AMP production and protein kinase A (PKA) activity. This was associated with a nuclear translocation of the PKA catalytic subunit and with a PKA-dependent phosphorylation of the CRE-binding protein (CREB) at Ser(133). Using transient transfection experiments and reporter luciferase assays, we show that peptone-stimulated transcriptional activity of the CCK gene promoter was significantly decreased when the PKA pathway was inhibited. Furthermore, the intracellular calcium chelator 1,2-bis-(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-tetra(acetoxymethyl)ester completely inhibited peptone-induced stimulation of the CCK gene promoter activity, phosphorylation of CREB, and PKA activity. Peptones increased, in a calcium-dependent manner, the phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and the MEK inhibitor PD98059 decreased the peptone-induced stimulation of CCK gene promoter activity. This stimulation was also reduced by 30% in the presence of the calcium/calmodulin-dependent protein kinase (CaMK) inhibitor KN-93. Total inhibition was obtained when the PKA, ERK, and CaMK pathways were simultaneously blocked with appropriate inhibitors to these pathways. These results demonstrate the simultaneous involvement of cAMP- and calcium-dependent protein kinases in the stimulation of intestinal CCK gene transcription by protein-derived nutrients.
Gevrey
Jean-Claude
JC
INSERM Unité 45 and IFR 62, Hôpital Edouard Herriot, Pavillon H, F-69437 Lyon Cedex 3, France.
Cordier-Bussat
Martine
M
Némoz-Gaillard
Eric
E
Chayvialle
Jean-Alain
JA
Abello
Jacques
J
D020816:Amino Acid Motifs; D001596:Benzylamines / Q000494:pharmacology; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002766:Cholecystokinin / Q000235:genetics* / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005799:Genes, Dominant; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010461:Peptones / Q000737:chemistry / Q000494:pharmacology; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D013449:Sulfonamides / Q000494:pharmacology; D013997:Time Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D000096926:Benzenesulfonamides
D001596:Benzylamines; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002766:Cholecystokinin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D004791:Enzyme Inhibitors; D005419:Flavonoids; D008156:Luciferases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010461:Peptones; D012694:Serine; D013449:Sulfonamides; C072105:KN 93; D000096926:Benzenesulfonamides; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one