scholarly journals Non-Canonical Activation of CREB Mediates Neuroprotection in a C. elegans Model of Excitotoxic Necrosis

2018 ◽  
Author(s):  
K. Genevieve Feldmann ◽  
Ayesha Chowdhury ◽  
Jessi Becker ◽  
N’Gina McAlpin ◽  
Taqwa Ahmed ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Neuroprotective Effect ◽  
Camp Response Element Binding ◽  
Creb Binding Protein ◽  
Creb Phosphorylation ◽  
C Elegans ◽  
Creb Activation ◽  
Specific Subset

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.

scholarly journals Recruitment of an RNA Polymerase II Complex Is Mediated by the Constitutive Activation Domain in CREB, Independently of CREB Phosphorylation

2001 ◽  
Vol 21 (4) ◽  
pp. 1001-1010 ◽  
Author(s):  
Edward A. Felinski ◽  
Jeonga Kim ◽  
Jingfang Lu ◽  
Patrick G. Quinn
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Creb Binding Protein ◽  
Transcription Activator ◽  
Activation Domain ◽  
Creb Phosphorylation ◽  
Constitutive Activation ◽  
Creb Activation

ABSTRACT The cAMP response element binding protein (CREB) is a bifunctional transcription activator, exerting its effects through a constitutive activation domain (CAD) and a distinct kinase inducible domain (KID), which requires phosphorylation of Ser-133 for activity. Both CAD and phospho-KID have been proposed to recruit polymerase complexes, but this has not been directly tested. Here, we show that the entire CREB activation domain or the CAD enhanced recruitment of a complex containing TFIID, TFIIB, and RNA polymerase II to a linked promoter. The nuclear extracts used mediated protein kinase A (PKA)-inducible transcription, but phosphorylation of CRG (both of the CREB activation domains fused to the Gal4 DNA binding domain) or KID-G4 did not mediate recruitment of a complex, and mutation of the PKA site in CRG abolished transcription induction by PKA but had no effect upon recruitment. The CREB-binding protein (CBP) was not detected in the recruited complex. Our results support a model for transcription activation in which the interaction between the CREB CAD and hTAFII130 of TFIID promotes the recruitment of a polymerase complex to the promoter.

scholarly journals Regulatory domains of the A-Myb transcription factor and its interaction with the CBP/p300 adaptor molecules

1997 ◽  
Vol 324 (3) ◽  
pp. 729-736 ◽  
Author(s):  
Valeria FACCHINETTI ◽  
Livio LOFFARELLI ◽  
Sabine SCHREEK ◽  
Michael OELGESCHLÄGER ◽  
Bernhard LÜSCHER ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Binding Activity ◽  
Myb Transcription Factor ◽  
Physical Interaction ◽  
Creb Binding Protein ◽  
Activation Domain ◽  
Activation Potential

The A-Myb transcription factor belongs to the Myb family of oncoproteins and is likely to be involved in the regulation of proliferation and/or differentiation of normal B cells and Burkitt's lymphoma cells. To characterize in detail the domains of A-Myb that regulate its function, we have generated a series of deletion mutants and have investigated their trans-activation potential as well as their DNA-binding activity. Our results have allowed us to delineate the trans-activation domain as well as two separate regulatory regions. The boundaries of the trans-activation domain (amino acid residues 218–319) are centred on a sequence rich in charged amino acids (residues 259–281). A region (residues 320–482) localized immediately downstream of the trans-activation domain and containing a newly identified conserved stretch of 48 residues markedly inhibits specific DNA binding. Finally the last 110 residues of A-Myb (residues 643–752), which include a sequence conserved in all mammalian myb genes (region III), negatively regulate the maximal trans-activation potential of A-Myb. We have also investigated the functional interaction between A-Myb and the nuclear adaptor molecule CBP [cAMP response element-binding protein (CREB)-binding protein]. We demonstrate that CBP synergizes with A-Myb in a dose-dependent fashion, and that this co-operative effect can be inhibited by E1A and can also be observed with the CBP homologue p300. We show that this functional synergism requires the presence of the A-Myb charged sequence and that it involves physical interaction between A-Myb and the CREB-binding domain of CBP.

scholarly journals Recruitment of CREB Binding Protein Is Sufficient for CREB-Mediated Gene Activation

2000 ◽  
Vol 20 (5) ◽  
pp. 1546-1552 ◽  
Author(s):  
Jean-Rene Cardinaux ◽  
John C. Notis ◽  
Qinghong Zhang ◽  
Ngan Vo ◽  
Johanna C. Craig ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Gene Activation ◽  
Activation Process ◽  
Creb Binding Protein ◽  
Protein Protein Interaction ◽  
Binding Domains ◽  
Phosphorylation Event ◽  
Element Binding Protein

ABSTRACT Phosphorylation of the transcription factor CREB leads to the recruitment of the coactivator, CREB binding protein (CBP). Recent studies have suggested that CBP recruitment is not sufficient for CREB function, however. We have identified a conserved protein-protein interaction motif within the CBP-binding domains of CREB and another transcription factor, SREBP (sterol-responsive element binding protein). In contrast to CREB, SREBP interacts with CBP in the absence of phosphorylation. We have exploited the conservation of this interaction motif to test whether CBP recruitment to CREB is sufficient for transcriptional activation. Substitution of six nonconserved amino acids from SREBP into the activation domain of CREB confers high-affinity, phosphorylation-independent CBP binding. The mutated CREB molecule, CREBDIEDML, activates transcription in F9 teratocarcinoma and PC12 cells even in the absence of protein kinase A (PKA). Addition of exogenous CBP augments the level of transcription mediated by CREBDIEDML, and adenovirus 12S E1A blocks transcription, implicating CBP in the activation process. Thus, recruitment of CBP to CREB is sufficient for transcriptional activation. Addition of PKA stimulates transcription induced by CREBDIEDML further, suggesting that a phosphorylation event downstream from CBP recruitment augments CREB signaling.

scholarly journals p53 Recruitment of CREB Binding Protein Mediated through Phosphorylated CREB: a Novel Pathway of Tumor Suppressor Regulation

2000 ◽  
Vol 20 (13) ◽  
pp. 4849-4858 ◽  
Author(s):  
Holli A. Giebler ◽  
Isabelle Lemasson ◽  
Jennifer K. Nyborg
Keyword(s):  
Tumor Suppressor ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Direct Interaction ◽  
Creb Binding Protein ◽  
Creb Phosphorylation ◽  
Cellular Genes ◽  
Kix Domain ◽  
Phosphorylated Creb

ABSTRACT CREB binding protein (CBP) is a 270-kDa nuclear protein required for activated transcription of a large number of cellular genes. Although CBP was originally discovered through its interaction with phosphorylated CREB (pCREB), it is utilized by a multitude of cellular transcription factors and viral oncoproteins. Both CREB and the tumor suppressor p53 have been shown to directly interact with the KIX domain of CBP. Although coactivator competition is an emerging theme in transcriptional regulation, we have made the fortuitous observation that protein kinase A-phosphorylated CREB strongly enhances p53 association with KIX. Phosphorylated CREB also facilitates interaction of a p53 mutant, defective for KIX binding, indicating that CREB functions in a novel way to bridge p53 and the coactivator. This is accomplished through direct interaction between the bZIP domain of CREB and the amino terminus of p53; a protein-protein interaction that is also detected in vivo. Consistent with our biochemical observations, we show that stimulation of the intracellular cyclic AMP (cAMP) pathway, which leads to CREB phosphorylation, strongly enhances both the transcriptional activation and apoptotic properties of p53. We propose that phosphorylated CREB mediates recruitment of CBP to p53-responsive promoters through direct interaction with p53. These observations provide evidence for a novel pathway that integrates cAMP signaling and p53 transcriptional activity.

scholarly journals Metformin Inhibits Androgen-Induced IGF-IR Up-Regulation in Prostate Cancer Cells by Disrupting Membrane-Initiated Androgen Signaling

Endocrinology ◽  
2014 ◽  
Vol 155 (4) ◽  
pp. 1207-1221 ◽  
Author(s):  
Roberta Malaguarnera ◽  
Antonella Sacco ◽  
Alaide Morcavallo ◽  
Sebastiano Squatrito ◽  
Antimo Migliaccio ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Gene Transcription ◽  
Binding Protein ◽  
Biological Effects ◽  
Creb Binding Protein ◽  
Prostate Cancer Cells ◽  
Creb Phosphorylation ◽  
Creb Activation ◽  
Igf I

We have previously demonstrated that, in prostate cancer cells, androgens up-regulate IGF-I receptor (IGF-IR) by inducing cAMP-response element-binding protein (CREB) activation and CREB-dependent IGF-IR gene transcription through androgen receptor (AR)-dependent membrane-initiated effects. This IGF-IR up-regulation is not blocked by classical antiandrogens and sensitizes cells to IGF-I-induced biological effects. Metformin exerts complex antitumoral functions in various models and may inhibit CREB activation in hepatocytes. We, therefore, evaluated whether metformin may affect androgen-dependent IGF-IR up-regulation. In the AR+ LNCaP prostate cancer cells, we found that metformin inhibits androgen-induced CRE activity and IGF-IR gene transcription. CRE activity requires the formation of a CREB-CREB binding protein-CREB regulated transcription coactivator 2 (CRTC2) complex, which follows Ser133-CREB phosphorylation. Metformin inhibited Ser133-CREB phosphorylation and induced nuclear exclusion of CREB cofactor CRTC2, thus dissociating the CREB-CREB binding protein-CRTC2 complex and blocking its transcriptional activity. Similarly to metformin action, CRTC2 silencing inhibited IGF-IR promoter activity. Moreover, metformin blocked membrane-initiated signals of AR to the mammalian target of rapamycin/p70S6Kinase pathway by inhibiting AR phosphorylation and its association with c-Src. AMPK signals were also involved to some extent. By inhibiting androgen-dependent IGF-IR up-regulation, metformin reduced IGF-I-mediated proliferation of LNCaP cells. These results indicate that, in prostate cancer cells, metformin inhibits IGF-I-mediated biological effects by disrupting membrane-initiated AR action responsible for IGF-IR up-regulation and suggest that metformin could represent a useful adjunct to the classical antiandrogen therapy.

scholarly journals Phosphodiesterase-2 inhibitor reverses corticosterone-induced neurotoxicity and related behavioural changes via cGMP/PKG dependent pathway

2013 ◽  
Vol 16 (4) ◽  
pp. 835-847 ◽  
Author(s):  
Ying Xu ◽  
Jianchun Pan ◽  
Ling Chen ◽  
Chong Zhang ◽  
Jiao Sun ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Hippocampal Neurons ◽  
Binding Protein ◽  
Neuroprotective Effect ◽  
Adenosine Monophosphate ◽  
Camp Response Element Binding ◽  
Guanosine Monophosphate ◽  
Mrna Levels ◽  
Creb Binding Protein ◽  
Dependent Pathway

Abstract Phosphodiesterase 2 (PDE2) is an enzyme responsible for hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) to restrict intracellular signalling of these second messenger molecules. This study investigated how PDE2 inhibitor Bay 60-7550 affects the dysregulated glucocorticoid signalling in neuronal cells and regulates depressive behaviours after chronic stress in mice. We found that exposure of hippocampal neurons to corticosterone resulted in time- and concentration-dependent increases in PDE2 expression. These intriguing findings were confirmed in the hippocampal cell line HT-22. After corticosterone exposure for 24 h, HT-22 cells showed a concentration-dependent increase in mRNA levels for PDE2 subtypes, PDE2A1 and 2A3, as well as for the total PDE2A protein expression. Bay 60-7550 was found to reverse the cell lesion induced by corticosterone (50 µm). This neuroprotective effect was blocked by pretreatment with protein kinase G inhibitor KT5823, but not protein kinase A inhibitor H89, suggesting the involvement of cGMP-dependent signalling. Although Bay 60-7550 treatment for 24 h did not change the levels of phosphorylated mitogen-activated protein kinases ERK1/2 (pERK) and phosphorylated cAMP response element-binding protein (pCREB), it down-regulated pERK at 2 h and up-regulated a CREB co-activator, CREB-binding protein, at 24 h. Both of these effects were blocked by KT 5823. Furthermore, Bay 60-7550 reversed corticosterone-induced down-regulation of brain-derived neurotrophic factor protein levels 24 h after corticosterone exposure. In behavioural testing, Bay 60-7550 produced antidepressant-like effects and reduced corticosterone levels in stressed mice, further supporting the involvement of a PDE2-dependent pathway in mediating Bay 60-7550's effect during stress hormone insults.

The transcriptional activity of Pygopus is enhanced by its interaction with cAMP-response-element-binding protein (CREB)-binding protein

2009 ◽  
Vol 422 (3) ◽  
pp. 493-501 ◽  
Author(s):  
Phillip G. P. Andrews ◽  
Zhijian He ◽  
Cathy Popadiuk ◽  
Kenneth R. Kao
Keyword(s):  
Histone Acetylation ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Histone Acetyltransferase ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Creb Binding Protein ◽  
Hek 293 ◽  
Element Binding Protein

Pygopus is a core component of the β-catenin/TCF (T-cell factor) transcriptional activation complex required for the expression of canonical Wnt target genes. Recent evidence suggests that Pygopus could interpret histone methylation associated with target genes and it was shown to be required for histone acetylation. The involvement of a specific acetyltransferase, however, was not determined. In this report, we demonstrate that Pygopus can interact with the HAT (histone acetyltransferase) CBP [CREB (cAMP-responsive-element-binding protein)-binding protein]. The interaction is via the NHD (N-terminal homology domain) of Pygopus, which binds to two regions in the vicinity of the HAT domain of CBP. Transfected and endogenous hPygo2 (human Pygopus2) and CBP proteins co-immunoprecipitate in HEK-293 (human embryonic kidney 293) cells and both proteins co-localize in SW480 colorectal cancer cells. The interaction with CBP also enhances both DNA-tethered and TCF/LEF1 (lymphoid enhancing factor 1)-dependent transcriptional activity of Pygopus. Furthermore, immunoprecipitated Pygopus protein complexes displayed CBP-dependent histone acetyltransferase activity. Our data support a model in which the NHD region of Pygopus is required to augment TCF/β-catenin-mediated transcriptional activation by a mechanism that includes both transcriptional activation and histone acetylation resulting from the recruitment of the CBP histone acetyltransferase.

Prostaglandin-E2 enhances EPO-mediated STAT5 transcriptional activity by serine phosphorylation of CREB

Blood ◽  
2002 ◽  
Vol 100 (2) ◽  
pp. 467-473 ◽  
Author(s):  
Arjen-Kars Boer ◽  
A. Lyndsay Drayer ◽  
Hallgeir Rui ◽  
Edo Vellenga
Keyword(s):  
Prostaglandin E2 ◽  
Target Genes ◽  
Binding Protein ◽  
Phosphodiesterase Inhibitor ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Camp Response Element Binding ◽  
Serine Phosphorylation ◽  
Creb Binding Protein ◽  
Creb Phosphorylation

Abstract Erythroid colony formation in response to erythropoietin (EPO) stimulation is enhanced by costimulating the cells with prostaglandin-E2 (PGE2). The present study further analyzed the underlying mechanisms and demonstrated that EPO-mediated STAT5 transactivation in the erythroid AS-E2 cell line was enhanced 6-fold by PGE2 (10 μM), without affecting the STAT5 tyrosine phosphorylation or STAT5-DNA binding. Moreover, the PGE2-enhancing effect was independent of STAT5 serine phosphorylation. In AS-E2 cells STAT5 is constitutively phosphorylated on Ser780 (STAT5A) and EPO-dependently phosphorylated on Ser726/731 (STAT5A/STAT5B), but overexpression of STAT5 serine mutants did not affect STAT5 transactivation. In addition, PGE2 did not affect STAT5 serine phosphorylation. Instead, the stimulatory effect of PGE2 on STAT5 signaling could be mimicked by dibutyryl-cyclic adenosine monophosphate (cAMP) and the phosphodiesterase inhibitor IBMX, suggesting that the effect was mediated by cAMP. Activation of the cAMP pathway resulted in cAMP-response element binding protein (CREB) phosphorylation, which was sustained in the presence of EPO plus PGE2 and transient on EPO stimulation alone. The costimulatory effect of PGE2 on EPO-mediated STAT5 transactivation was inhibited by overexpression of serine-dead CREB or protein kinase A (PKA) inhibitor (PKI), in contrast to EPO-mediated transactivation, which was PKA independent. Furthermore, CREB-binding protein (CBP)/p300 was shown to be involved in EPO-mediated STAT5 transactivation, and a CBP mutant with increased affinity for CREB resulted in an additional enhancement of the PGE2 effect. Finally, we demonstrated that the STAT5 target genes Bcl-X, SOCS2, andSOCS3 were up-regulated by costimulation with PGE2. In summary, these studies demonstrate that PGE2 enhancement of EPO-induced STAT5 transactivation is mediated by the cAMP/PKA/CREB pathway.

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