title: Daxx interacts with and modulates the activity of CREB.
abstract: The phosphorylation of cAMP response element-binding protein (CREB) induced by the cAMP-dependent protein kinase A (PKA) elicits the recruitment of CREB-binding protein (CBP) for activating cAMP responsive gene expression. Several reports indicate that proteins binding to CREB and/or CBP play important roles in modulating the CREB-dependent transactivation. Here, we show that Daxx interacts with CREB and modulates CREB-mediated transcription. Daxx was identified as a CREB-interacting protein by a yeast two-hybrid screen. Depletion of endogenous Daxx by specific shRNA or overexpression of Daxx resulted in decreased or increased levels of the cAMP/PKA-induced reporter activity and target gene expression, respectively. In vitro and in vivo binding studies revealed that Daxx C-terminal domain binds to CREB basic leucine zipper domain. The binding of Daxx to CREB correlates with its repressive effect on a CRE-mediated reporter activity induced by forskolin or PKA. Furthermore, the results of electrophoresis mobility shift assays and chromatin immunoprecipitation experiments showed that Daxx attenuated the DNA binding potential of the CREB. Our study provides a previously undescribed role of Daxx in repressing cAMP-responsive gene expression and also a mechanism underlying the repressive effect of Daxx on CREB transcriptional potential.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China.
authors.forename: Yen-Sung
authors.initials: YS
authors.lastname: Huang
authors.forename: Che-Chang
authors.initials: CC
authors.lastname: Chang
authors.forename: Tien-Chi
authors.initials: TC
authors.lastname: Huang
authors.forename: Yung-Lin
authors.initials: YL
authors.lastname: Hsieh
authors.forename: Hsiu-Ming
authors.initials: HM
authors.lastname: Shih
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D050882:CREB-Binding Protein / Q000378:metabolism; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D056970:Co-Repressor Proteins; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D006801:Humans; D016350:Leucine Zippers; D051379:Mice; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D056970:Co-Repressor Proteins; D017362:Cyclic AMP Response Element-Binding Protein; C106985:DAXX protein, human; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D004247:DNA; D050882:CREB-Binding Protein; D017868:Cyclic AMP-Dependent Protein Kinases