1. PKC-dependent phosphorylation of the p97 repressor regulates the transcription of aldolase A L-type promoter
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Paola Costanzo, Paola D'Agostino, Paola Izzo, Chiara Zevino, Angelo Lupo, L. Medugno, Costanzo, Paola, Lupo, A., Medugno, L., D'Agostino, P., Zevino, C., Izzo, P., Costanzo, P, Lupo, A, Medugno, L, D'Agostino, P, Zevino, C, and Izzo, Paola
- Subjects
Time Factors ,Transcription, Genetic ,Recombinant Fusion Proteins ,Biophysics ,Repressor ,Biology ,Cell cycle ,Biochemistry ,Models, Biological ,Dephosphorylation ,Mice ,Transcriptional regulation ,Structural Biology ,Transcription (biology) ,Protein kinase C ,Fructose-Bisphosphate Aldolase ,Genetics ,Animals ,Humans ,Phosphorylation ,Promoter Regions, Genetic ,Molecular Biology ,Messenger RNA ,Dose-Response Relationship, Drug ,Negative cis element ,Aldolase A ,Nuclear Proteins ,Cell Biology ,3T3 Cells ,Molecular biology ,Repressor Proteins ,biology.protein ,Caco-2 Cells - Abstract
Expression of mouse aldolase A L-type mRNA is negatively modulated by a cis element (AldA-NRE), located within the aldolase A distal promoter (pL). AldA-NRE interacts with a 97-kDa repressor protein (p97), which binds DNA in a cell cycle-dependent manner. We demonstrate that the binding between AldA-NRE and p97 decreases during differentiation of human Caco-2 cells and is inversely correlated with L-type mRNA expression. Phosphorylation of the p97 repressor weakened its DNA binding activity in differentiated Caco-2 cells, while dephosphorylation enhanced the binding in proliferating cells. Stimulation of protein kinase C (PKC) in vivo decreased the binding of p97 to AldA-NRE and stimulated transcription, while inhibition of PKC stimulated p97 binding and downregulated transcription. These findings suggest that PKC is a mediator of the binding and silencing function of the p97/AldA-NRE repressor complex. Copyright (C) 1999 Federation of European Biochemical Societies.
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