Cyclic AMP stimulates somatostatin gene transcription by phosphorylation of CREB at serine 133.
In this paper, we demonstrate that phosphorylation of CREB at Ser-133 is induced 6-fold in vivo, following treatment of PC12 cells with forskolin. By contrast, no such induction was observed in the kinase A-deficient PC12 line A126-1B2 (A126). Using F9 teratocarcinoma cells, which are unresponsive to cAMP, we initiated a series of transient expression experiments to establish a causal link between phosphorylation of CREB and trans-activation of cAMP-responsive genes. Inactivating the kinase A phosphorylation site by in vitro mutagenesis of the cloned CREB cDNA at Ser-133 completely abolished CREB transcriptional activity. As CREB mutants containing acidic residues in place of the Ser-133 phosphoacceptor were also transcriptionally inactive, these results suggest that phosphorylation of CREB may stimulate transcription by a mechanism other than by simply providing negative charge.
Gonzalez
G A
GA
Clayton Foundation Laboratory for Peptide Biology, Salk Institute, La Jolla, California 92037.
Montminy
M R
MR
D000310:Adrenal Gland Neoplasms; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology*; D000242:Cyclic AMP / Q000502:physiology*; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D005796:Genes / Q000187:drug effects*; D008969:Molecular Sequence Data; D009154:Mutation; D010449:Peptide Mapping; D010673:Pheochromocytoma; D010766:Phosphorylation; D051381:Rats; D012694:Serine; D013004:Somatostatin / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection
D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D005576:Colforsin; D012694:Serine; D013004:Somatostatin; D000242:Cyclic AMP