scholarly journals The Transcriptional Coactivator CREB-binding Protein Cooperates with STAT1 and NF-κB for Synergistic Transcriptional Activation of the CXC Ligand 9/Monokine Induced by Interferon-γ Gene

2002 ◽  
Vol 278 (1) ◽  
pp. 651-660 ◽  
Author(s):  
Miki Hiroi ◽  
Yoshihiro Ohmori
2000 ◽  
Vol 20 (5) ◽  
pp. 1616-1625 ◽  
Author(s):  
Yang Chen ◽  
R. H. Goodman ◽  
Sarah M. Smolik

ABSTRACT CREB-binding protein (CBP) serves as a transcriptional coactivator in multiple signal transduction pathways. The Drosophilahomologue of CBP, dCBP, interacts with the transcription factors Cubitus interruptus (CI), MAD, and Dorsal (DL) and functions as a coactivator in several signaling pathways during Drosophiladevelopment, including the hedgehog (hh),decapentaplegic (dpp), and Tollpathways. Although dCBP is required for the expression of thehh target genes, wingless (wg) andpatched (ptc) in vivo, and potentiatesci-mediated transcriptional activation in vitro, it is not known that ci absolutely requires dCBP for its activity. We used a yeast genetic screen to identify several ci point mutations that disrupt CI-dCBP interactions. These mutant proteins are unable to transactivate a reporter gene regulated by cibinding sites and have a lower dCBP-stimulated activity than wild-type CI. When expressed exogenously in embryos, the CI point mutants cannot activate endogenous wg expression. Furthermore, a CI mutant protein that lacks the entire dCBP interaction domain functions as a negative competitor for wild-type CI activity, and the expression of dCBP antisense RNAs can suppress CI transactivation in Kc cells. Taken together, our data suggest that dCBP function is necessary forci-mediated transactivation of wg duringDrosophila embryogenesis.


2000 ◽  
Vol 20 (4) ◽  
pp. 1299-1310 ◽  
Author(s):  
Xiaoya Zeng ◽  
Xiaorong Li ◽  
Ashley Miller ◽  
Zhimin Yuan ◽  
Wuchao Yuan ◽  
...  

ABSTRACT The newly identified p53 homolog p73 mimics the transcriptional function of p53. We have investigated the regulation of p73's transcriptional activity by p300/CREB binding protein (CBP). p73-p300 complexes were identified in HeLa cell extracts by cofractionation and coimmunoprecipitation assays. The p73-p300 interaction was confirmed in vitro by glutathione S-transferase–protein association assays and in vivo by coimmunoprecipitating the overexpressed p300 and p73 in human p53-free small-cell lung carcinoma H1299 or osteosarcoma Saos-2 cells. The N terminus but not the N-terminal truncation of p73 bound to the CH1 domain (amino acids [aa] 350 to 450) of p300/CBP. Accordingly, this p73 N-terminal deletion was unable to activate transcription or to induce apoptosis. Overexpression of either p300 or CBP stimulated transcription mediated by p73 but not its N-terminally deleted mutant in vivo. The N-terminal fragment from aa 19 to 597, but not the truncated fragment from aa 242 to 1700 of p300, reduced p73-mediated transcription markedly. p73-dependent transcription or apoptosis was partially impaired in either p300- or CBP-deficient human breast carcinoma MCF-7 or H1299 cells, suggesting that both coactivators mediate transcription by p73 in cells. These results demonstrate that the N terminus of p73 directly interacts with the N-terminal CH1 domain of p300/CBP to activate transcription.


2004 ◽  
Vol 14 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Toshihiro Nakajima ◽  
Satoko Aratani ◽  
Minako Nakazawa ◽  
Takuji Hirose ◽  
Hidetoshi Fujita ◽  
...  

2018 ◽  
Author(s):  
K. Genevieve Feldmann ◽  
Ayesha Chowdhury ◽  
Jessi Becker ◽  
N’Gina McAlpin ◽  
Taqwa Ahmed ◽  
...  

AbstractExcitotoxicity, caused by exaggerated neuronal stimulation by Glutamate (Glu), is a major cause of neurodegeneration in brain ischemia. While we know that neurodegeneration is triggered by overstimulation of Glu-Receptors (GluRs), the subsequent mechanisms that lead to cellular demise remain controversial. Surprisingly, signaling downstream of GluRs can also activate neuroprotective pathways. The strongest evidence involves activation of the transcription factor cAMP Response Element Binding-protein (CREB), widely recognized for its importance in synaptic plasticity. Canonical views describe CREB as a phosphorylation-triggered transcription factor, where transcriptional activation involves CREB phosphorylation and association with CREB Binding Protein (CBP). However, given CREB’s ubiquitous cross-tissue expression, the multitude of cascades leading to CREB phosphorylation, and its ability to regulate thousands of genes, it remains unclear how CREB exerts closely-tailored, differential neuroprotective responses in excitotoxicity. A non-canonical, alternative cascade for activation of CREB-mediated transcription involves the CREB co-factor cAMP-regulated transcriptional co-activator (CRTC), and may be independent of CREB phosphorylation. To identify cascades that activate CREB in excitotoxicity we use a C. elegans model of neurodegeneration by excitotoxic necrosis. We demonstrate that CREB’s neuroprotective effect is conserved, and seems most effective in neurons with moderate Glu exposure. We find that factors mediating canonical CREB activation are not involved. Instead, phosphorylation-independent CREB activation in nematode excitotoxic necrosis hinges on CRTC. CREB-mediated transcription that depends on CRTC, but not on CREB phosphorylation, might lead to expression of a specific subset of neuroprotective genes. Elucidating conserved mechanisms of excitotoxicity-specific CREB activation can help us focus on core neuroprotective programs in excitotoxicity.


2002 ◽  
Vol 22 (22) ◽  
pp. 7769-7779 ◽  
Author(s):  
Séverine Boulon ◽  
Jean-Christophe Dantonel ◽  
Virginie Binet ◽  
Annick Vié ◽  
Jean-Marie Blanchard ◽  
...  

ABSTRACT Cyclin D1, the regulatory subunit for mid-G1 cyclin-dependent kinases, controls the expression of numerous cell cycle genes. A cyclic AMP-responsive element (CRE), located upstream of the cyclin D1 mRNA start site, integrates mitogenic signals that target the CRE-binding factor CREB, which can recruit the transcriptional coactivator CREB-binding protein (CBP). We describe an alternative mechanism for CREB-driven cyclin D1 induction that involves the ubiquitous POU domain protein Oct-1. In the breast cancer cell line MCF-7, overexpression of Oct-1 or its POU domain strongly increases transcriptional activation of cyclin D1 and GAL4 reporter genes that is specifically dependent upon CREB but independent of Oct-1 DNA binding. Gel retardation and chromatin immunoprecipitation assays confirm that POU forms a complex with CREB bound to the cyclin D1 CRE. In solution, CREB interaction with POU requires the CREB Q2 domain and, notably, occurs with CREB that is not phosphorylated on Ser 133. Accordingly, Oct-1 also potently enhances transcriptional activation mediated by a Ser133Ala CREB mutant. Oct-1/CREB synergy is not diminished by the adenovirus E1A 12S protein, a repressor of CBP coactivator function. In contrast, E1A strongly represses CBP-enhanced transactivation by CREB phosphorylated on Ser 133. Our observation that Oct-1 potentiates CREB-dependent cyclin D1 transcriptional activity independently of Ser 133 phosphorylation and E1A-sensitive coactivator function offers a new paradigm for the regulation of cyclin D1 induction by proliferative signals.


2000 ◽  
Vol 149 (2) ◽  
pp. 249-254 ◽  
Author(s):  
Ken-Ichi Takemaru ◽  
Randall T. Moon

β-Catenin plays a pivotal role in the transcriptional activation of Wnt-responsive genes by binding to TCF/LEF transcription factors. Although it has been suggested that the COOH-terminal region of β-catenin functions as an activation domain, the mechanisms of activation remain unclear. To screen for potential transcriptional coactivators that bind to the COOH-terminal region of β-catenin, we used a novel yeast two-hybrid system, the Ras recruitment system (RRS) that detects protein–protein interactions at the inner surface of the plasma membrane. Using this system, we isolated the CREB-binding protein (CBP). Armadillo (Arm) repeat 10 to the COOH terminus of β-catenin is involved in binding to CBP, whereas β-catenin interacts directly with the CREB-binding domain of CBP. β-Catenin synergizes with CBP to stimulate the activity of a synthetic reporter in vivo. Conversely, β-catenin–dependent transcriptional activation is repressed by E1A, an antagonist of CBP function, but not by an E1A mutant that does not bind to CBP. The activation of Wnt target genes such as siamois and Xnr3 in Xenopus embryos is also sensitive to E1A. These findings suggest that CBP provides a link between β-catenin and the transcriptional machinery, and possibly mediates the oncogenic function of β-catenin.


Sign in / Sign up

Export Citation Format

Share Document