Phosphorylation of conserved casein kinase sites regulates cAMP-response element-binding protein DNA binding in Drosophila.
The Drosophila homolog of cAMP-response element-binding protein (CREB), dCREB2, exists with serine 231, equivalent to mammalian serine 133, in a predominantly phosphorylated state. Thus, unlike the mammalian protein, the primary regulation of dCREB2 may occur at a different step from serine 231 phosphorylation. Although bacterially expressed dCREB2 bound cAMP-response element sites, protein from Drosophila extracts was unable to do so unless treated with phosphatase. Phosphorylation of recombinant protein by casein kinase (CK) I or II, but not calcium-calmodulin kinase II or protein kinase A, inhibited DNA binding. Up to four conserved CK sites likely to be phosphorylated in vivo were responsible for this effect, and these sites were phosphorylated by a kinase present in Drosophila cell extracts that biochemically resembles CKII. We propose that the relative importance of different signaling pathways in regulating CREB activity may differ between Drosophila and mammals. In Drosophila, the dephosphorylation of CK sites appears to be the major regulatory step, while phosphorylation of serine 231 is necessary but secondary.
Horiuchi
Junjiro
J
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Jiang
Wei
W
Zhou
Hong
H
Wu
Priscilla
P
Yin
Jerry C P
JC
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D047388:Casein Kinases; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004330:Drosophila; D004331:Drosophila melanogaster / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000737:chemistry; D019076:Transgenes
D017362:Cyclic AMP Response Element-Binding Protein; D010455:Peptides; D011994:Recombinant Proteins; D012694:Serine; D004247:DNA; D000242:Cyclic AMP; D011494:Protein Kinases; D047388:Casein Kinases