scholarly journals Involvement of Transducer of Regulated cAMP Response Element-Binding Protein Activity on Corticotropin Releasing Hormone Transcription

Endocrinology ◽  
2010 ◽  
Vol 151 (3) ◽  
pp. 1109-1118 ◽  
Author(s):  
Ying Liu ◽  
Ana G. Coello ◽  
Valery Grinevich ◽  
Greti Aguilera
Keyword(s):  
Promoter Activity ◽  
Nuclear Translocation ◽  
Binding Protein ◽  
Primary Cultures ◽  
Camp Response Element Binding ◽  
Neuronal Cultures ◽  
Dependent Manner ◽  
Camp Response Element ◽  
Response Element ◽  
Element Binding Protein

We have recently shown that phospho-cAMP response element-binding protein (CREB) is essential but not sufficient for activation of CRH transcription, suggesting the requirement of a coactivator. Here, we test the hypothesis that the CREB coactivator, transducer of regulated CREB activity (TORC), is required for activation of CRH transcription, using the cell line 4B and primary cultures of hypothalamic neurons. Immunohistochemistry and Western blot experiments in 4B cells revealed time-dependent nuclear translocation of TORC1,TORC 2, and TORC3 by forskolin [but not by the phorbol ester, phorbol 12-myristate 13-acetate (PMA)] in a concentration-dependent manner. In reporter gene assays, cotransfection of TORC1 or TORC2 potentiated the stimulatory effect of forskolin on CRH promoter activity but had no effect in cells treated with PMA. Knockout of endogenous TORC using silencing RNA markedly inhibited forskolin-activated CRH promoter activity in 4B cells, as well as the induction of endogenous CRH primary transcript by forskolin in primary neuronal cultures. Coimmunoprecipitation and chromatin immunoprecipitation experiments in 4B cells revealed association of CREB and TORC in the nucleus, and recruitment of TORC2 by the CRH promoter, after 20-min incubation with forskolin. These studies demonstrate a correlation between nuclear translocation of TORC with association to the CRH promoter and activation of CRH transcription. The data suggest that TORC is required for transcriptional activation of the CRH promoter by acting as a CREB coactivator. In addition, cytoplasmic retention of TORC during PMA treatment is likely to explain the failure of phorbolesters to activate CRH transcription in spite of efficiently phosphorylating CREB.

scholarly journals Adrenergic Regulation of the Distribution of Transducer of Regulated cAMP-Response Element-Binding Protein (TORC2) in Rat Pinealocytes

Endocrinology ◽  
2011 ◽  
Vol 152 (9) ◽  
pp. 3440-3450 ◽  
Author(s):  
R. Kanyo ◽  
N. Amyotte ◽  
J. McTague ◽  
C. L. Chik ◽  
A. K. Ho
Keyword(s):  
Pineal Gland ◽  
Protein Phosphatase ◽  
Nuclear Translocation ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Response Element ◽  
Adrenergic Antagonist ◽  
Element Binding Protein ◽  
Rat Pineal Gland

Transducers of regulated cAMP-response element-binding protein (CREB) activity (TORC) are coactivators that can increase CREB transcriptional activity, suggesting that TORC may regulate the transcription of Aanat, a CREB-target gene. In the present study, we focused on the regulation of TORC2 and its role in Aanat transcription in the rat pineal gland. Although there was no endogenous Torc2 mRNA rhythm in the rat pineal gland and treatment of cultured pinealocytes with norepinephrine (NE) had no effect on the mRNA level of Torc2, the phosphorylation state and intracellular distribution of TORC2 protein were regulated by NE. Immunoblot analysis combined with cytosolic/nuclear fractionation or phosphatase treatment showed that TORC2 protein was rapidly dephosphorylated and translocated to the nucleus after NE stimulation in rat pinealocytes. Similar dephosphorylation of TORC2 also occurred nocturnally in the rat pineal gland. The NE-mediated TORC2 dephosphorylation was blocked by cotreatment with propranolol (a β-adrenergic antagonist) but not prazosin (an α1-adrenergic antagonist) and mimicked by dibutyryl cAMP, indicating the participation of the β-adrenergic receptor/cAMP pathway. Studies with protein phosphatase inhibitors showed that only okadaic acid and calyculin A were effective in blocking the NE-mediated TORC2 dephosphorylation, suggesting the involvement of protein phosphatase 2A in this dephosphorylation. Moreover, TORC2 overexpression had an enhancing effect on NE-stimulated Aanat transcription. Together, these results indicate that NE stimulation causes nuclear translocation of TORC2 by dephosphorylating the protein through a β-adrenoceptor/cAMP mechanism and that nuclear localization of TORC2 appears to regulate Aanat transcription by NE in the rat pineal gland.

scholarly journals Regulation of Steroidogenesis and the Steroidogenic Acute Regulatory Protein by a Member of the cAMP Response-Element Binding Protein Family

2002 ◽  
Vol 16 (1) ◽  
pp. 184-199 ◽  
Author(s):  
Pulak R. Manna ◽  
Matthew T. Dyson ◽  
Darrell W. Eubank ◽  
Barbara J. Clark ◽  
Enzo Lalli ◽  
...  
Keyword(s):  
Family Member ◽  
Promoter Activity ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Response Element ◽  
Star Protein ◽  
Element Binding Protein ◽  
Steroidogenic Acute Regulatory ◽  
Star Gene

Abstract The mitochondrial phosphoprotein, the steroidogenic acute regulatory (StAR) protein, is an essential component in the regulation of steroid biosynthesis in adrenal and gonadal cells through cAMP-dependent pathways. In many cases transcriptional induction by cAMP is mediated through the interaction of a cAMP response-element binding protein (CREB) family member with a consensus cAMP response element (CRE; 5′-TGACGTCA-3′) found in the promoter of target genes. The present investigation was carried out to determine whether a CRE-binding protein (CREB) family member [CREB/CRE modulator (CREM) family] was involved in the regulation of steroidogenesis and StAR protein expression. Transient expression of wild- type CREB in MA-10 mouse Leydig tumor cells further increased the levels of (Bu)2cAMP-induced progesterone synthesis, StAR promoter activity, StAR mRNA, and StAR protein. These responses were significantly inhibited by transfection with a dominant-negative CREB (A-CREB), or with a CREB mutant that cannot be phosphorylated (CREB-M1), the latter observation indicating the importance of phosphorylation of a CREB/CREM family member in steroidogenesis and StAR expression. The CREB/CREM-responsive region in the mouse StAR gene was located between −110 and −67 bp upstream of the transcriptional start site. An oligonucleotide probe (−96/−67 bp) containing three putative half-sites for 5′-canonical CRE sequences (TGAC) demonstrated the formation of protein-DNA complexes in EMSAs with recombinant CREB protein as well as with nuclear extracts from MA-10 or Y-1 mouse adrenal tumor cells. The predominant binding factor observed with EMSA was found to be the CREM protein as demonstrated using specific antibodies and RT-PCR analyses. The CRE elements identified within the− 96/−67 bp region were tested for cAMP responsiveness by generating mutations in each of the CRE half-sites either alone or in combination. Although each of the CRE sites contribute in part to the CREM response, the CRE2 appears to be the most important site as determined by EMSA and by reporter gene analyses. Binding specificity was further assessed using specific antibodies to CREB/CREM family members, cold competitors, and mutations in the target sites that resulted in either supershift and/or inhibition of these complexes. We also demonstrate that the inducible cAMP early repressor markedly diminished the endogenous effects of CREM on cAMP-induced StAR promoter activity and on StAR mRNA expression. These are the first observations to provide evidence for the functional involvement of a CREB/CREM family member in the acute regulation of trophic hormone-stimulated steroidogenesis and StAR gene expression.

scholarly journals Aberrant expression of cAMP-response-element-binding protein (‘CREB’) induces apoptosis

1999 ◽  
Vol 343 (1) ◽  
pp. 249-255 ◽  
Author(s):  
Kumiko SAEKI ◽  
Akira YUO ◽  
Emiko SUZUKI ◽  
Yoshio YAZAKI ◽  
Fumimaro TAKAKU
Keyword(s):  
Cell Cycle ◽  
Expression Vector ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Dependent Manner ◽  
Transactivation Domain ◽  
Camp Response Element ◽  
Response Element ◽  
Element Binding Protein ◽  
Induction Of Apoptosis

We have reported previously that cAMP-response-element-binding protein (CREB) was phosphorylated in a cell-cycle-dependent manner, showing that it was phosphorylated at early S-phase at casein kinase II target sites. To assess the possible involvement of CREB in cell cycle progression, CREB expression vector was transiently transfected into various cells. Unexpectedly we found that transfection with CREB expression vector resulted in an abundance of dead cells. Morphological examination revealed that these cells had undergone apoptosis. The coincidence of CREB overexpression and apoptosis induction at the individual cell level was confirmed by a immunohistochemical study. To confirm that overexpression of CREB was the cause of apoptosis, a dominant-negative mutant of CREB, KCREB, was co-expressed with the wild type. The co-existence of KCREB effectively rescued CREB-mediated apoptosis in a dose-dependent manner, verifying that apoptosis was truly a specific effect of overexpressed CREB and not an artifact of the transfection procedure. Deletion analysis indicates that neither the Q1 transactivation domain, which functions in transcription, nor the kinase-inducible domain, in which a cluster of various kinase targets exists, is necessary; however, the Q2 transactivation domain is required for the induction of apoptosis. A more precise study indicates that the four-residue stretch Glu-Glu-Ala-Ala at the most C-terminal region of the Q2 domain is especially important for the induction of apoptosis. Thus overexpressed CREB induces apoptosis by transmitting certain signals from the C-terminal portion of the Q2 domain. Possible roles of cell-cycle-regulated phosphorylation and also an elevation of the intracellular cAMP level in CREB-induced apoptosis are suggested.

scholarly journals Adenovirus-Directed Expression of a Nonphosphorylatable Mutant of CREB (cAMP Response Element-Binding Protein) Adversely Affects the Survival, but Not the Differentiation, of Rat Granulosa Cells

1999 ◽  
Vol 13 (8) ◽  
pp. 1364-1372 ◽  
Author(s):  
Jeremy P. Somers ◽  
Julie A. DeLoia ◽  
Anthony J. Zeleznik
Keyword(s):  
Granulosa Cells ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Primary Cultures ◽  
Adenovirus Vector ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Response Element ◽  
Luteal Cells ◽  
Element Binding Protein

Abstract Although usually considered to be a constitutively expressed protein, in the primate ovary the expression of CREB (cAMP response element-binding protein) is extinguished after ovulation, and its loss is temporally associated with the cessation of proliferation of luteal cells and the ultimate commitment of the corpus luteum to undergo regression. To determine the cellular consequences of the loss of CREB expression, we expressed a nonphosphorylatable mutant of CREB (CREB M1) in primary cultures of rat granulosa cells using a replication-defective adenovirus vector. Expression of CREB M1 did not block granulosa cell differentiation as assessed by acquisition of the ability to produce estrogen and progesterone in response to FSH or forskolin. However, granulosa cells expressing CREB M1, but not adenovirus-directed β-galactosidase or enhanced green fluorescent protein, exhibited a 35% reduction in viability that was further reduced to 65% after stimulation with 10 μm forskolin. These results demonstrate that the trophic effects of cAMP (proliferation and survival) on ovarian granulosa cells are functionally separate from the effects of cAMP on differentiation and provide novel evidence that CREB may function as a cell survival factor in the ovary. The separation of signaling pathways that govern differentiation and survival in the ovary thereby provides a mechanism by which progesterone production, which is absolutely essential for the maintenance of pregnancy, can continue despite the cessation of proliferation of luteal cells and their commitment to cell death (luteolysis).

Scutellarin Mitigates Cancer-Induced Bone Pain by Suppressing CaMKII/CREB Pathway in Rat Models

2019 ◽  
Vol 17 (3) ◽  
pp. 249-253
Author(s):  
Liu Chenglong ◽  
Liu Haihua ◽  
Zhang Fei ◽  
Zheng Jie ◽  
Wei Fang
Keyword(s):  
Protein Kinase ◽  
Bone Pain ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Dependent Protein Kinase ◽  
Response Element ◽  
Protein Kinase Ii ◽  
Element Binding Protein ◽  
Dependent Protein

Cancer-induced bone pain is a severe and complex pain caused by metastases to bone in cancer patients. The aim of this study was to investigate the analgesic effect of scutellarin on cancer-induced bone pain in rat models by intrathecal injection of Walker 256 carcinoma cells. Mechanical allodynia was determined by paw withdrawal threshold in response to mechanical stimulus, and thermal hyperalgesia was indicated by paw withdrawal latency in response to noxious thermal stimulus. The paw withdrawal threshold and paw withdrawal latencies were significantly decreased after inoculation of tumor cells, whereas administration of scutellarin significantly attenuated tumor cell inoculation-induced mechanical and heat hyperalgesia. Tumor cell inoculation-induced tumor growth was also significantly abrogated by scutellarin. Ca2+/calmodulin-dependent protein kinase II is a multifunctional kinase with up-regulated activity in bone pain models. The activation of Ca2+/calmodulin-dependent protein kinase II triggers phosphorylation of cAMP-response element binding protein. Scutellarin significantly reduced the expression of phosphorylated-Ca2+/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein in cancer-induced bone pain rats. Collectively, our study demonstrated that scutellarin attenuated tumor cell inoculation-induced bone pain by down-regulating the expression of phosphorylated-Ca2+/calmodulin-dependent protein kinase II and phosphorylated-cAMP-response element binding protein. The suppressive effect of scutellarin on phosphorylated-Ca2+/calmodulin-dependent protein kinase II/phosphorylated-cAMP-response element binding protein activation may serve as a novel therapeutic strategy for CIBP management.

cAMP Response Element Binding Protein Is Expressed and Phosphorylated in the Human Heart

Circulation ◽  
1995 ◽  
Vol 92 (8) ◽  
pp. 2041-2043 ◽  
Author(s):  
Frank Ulrich Müller ◽  
Peter Bokník ◽  
Andreas Horst ◽  
Jörg Knapp ◽  
Bettina Linck ◽  
...  
Keyword(s):  
Human Heart ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Response Element ◽  
Element Binding Protein
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