scholarly journals Expression of the Mouse Gonadotropin-Releasing Hormone Receptor Gene in αT3-1 Gonadotrope Cells Is Stimulated by Cyclic 3′,5′-Adenosine Monophosphate and Protein Kinase A, and Is Modulated by Steroidogenic Factor-1 and Nur77

Endocrinology ◽  
2003 ◽  
Vol 144 (5) ◽  
pp. 1958-1971 ◽  
Author(s):  
Hanél Sadie ◽  
Gustav Styger ◽  
Janet Hapgood
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Nuclear Receptor ◽  
Receptor Gene ◽  
Control Point ◽  
Negative Regulator ◽  
Mrna Levels ◽  
Orphan Nuclear Receptor ◽  
Steroidogenic Factor 1 ◽  
Kinase A

Regulation of GnRH receptor (GnRHR) expression levels in the pituitary is a crucial control point in reproduction. The promoter of the mouse GnRHR gene contains nuclear receptor half-sites (NRS) at –244/−236 and −15/−7 relative to the translation start site. Although binding of steroidogenic factor-1 (SF-1) to the –244/−236NRS is implicated in mediating basal and gonadotrope-specific expression, no function or protein-DNA interactions have previously been described for the –15/−7NRS. We report that levels of the endogenous GnRHR mRNA in αT3-1 cells are stimulated by forskolin and 8-bromo-cAMP. We also show that the orphan nuclear receptor Nur77 is expressed in αT3-1 cells, and that both SF-1 and Nur77 bind to the –15/−7NRS and –244/−236NRS in vitro. We show that the activity of the proximal (−579/+1) mouse GnRHR promoter is up-regulated by protein kinase A, via a mechanism that is modulated by SF-1, both positively and negatively, through binding to the –244/−236NRS or the –15/−7NRS, respectively. Nur77 appears to be capable of acting as a negative regulator of this response, via the –15/−7NRS. Furthermore, we show that forskolin up-regulates SF-1 mRNA levels in αT3-1 cells, indicating that the levels of SF-1 play a role in modulating the protein kinase A response.

scholarly journals Role of Dosage-Sensitive Sex Reversal, Adrenal Hypoplasia Congenita, Critical Region on the X Chromosome, Gene 1 in Protein Kinase A- and Protein Kinase C-Mediated Regulation of the Steroidogenic Acute Regulatory Protein Expression in Mouse Leydig Tumor Cells: Mechanism of Action

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 187-199 ◽  
Author(s):  
Pulak R. Manna ◽  
Matthew T. Dyson ◽  
Youngah Jo ◽  
Douglas M. Stocco
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Tumor Cells ◽  
Orphan Nuclear Receptor ◽  
Star Protein ◽  
Kinase C ◽  
Leydig Tumor Cells ◽  
Steroidogenic Acute Regulatory ◽  
Kinase A

Dosage-sensitive sex reversal, adrenal hypoplasia congenita, critical region on the X chromosome, gene 1 (DAX-1) is an orphan nuclear receptor that has been demonstrated to be instrumental to the expression of the steroidogenic acute regulatory (StAR) protein that regulates steroid biosynthesis in steroidogenic cells. However, its mechanism of action remains obscure. The present investigation was aimed at exploring the molecular involvement of DAX-1 in protein kinase A (PKA)- and protein kinase C (PKC)-mediated regulation of StAR expression and its concomitant impact on steroid synthesis using MA-10 mouse Leydig tumor cells. We demonstrate that activation of the PKA and PKC pathways, by a cAMP analog dibutyryl (Bu)2cAMP [(Bu)2cAMP] and phorbol 12-myristate 13-acetate (PMA), respectively, markedly decreased DAX-1 expression, an event that was inversely correlated with StAR protein, StAR mRNA, and progesterone levels. Notably, the suppression of DAX-1 requires de novo transcription and translation, suggesting that the effect of DAX-1 in regulating StAR expression is dynamic. Chromatin immunoprecipitation studies revealed the association of DAX-1 with the proximal but not the distal region of the StAR promoter, and both (Bu)2cAMP and PMA decreased in vivo DAX-1-DNA interactions. EMSA and reporter gene analyses demonstrated the functional integrity of this interaction by showing that DAX-1 binds to a DNA hairpin at position −44/−20 bp of the mouse StAR promoter and that the binding of DAX-1 to this region decreases progesterone synthesis by impairing transcription of the StAR gene. In support of this, targeted silencing of endogenous DAX-1 elevated basal, (Bu)2cAMP-, and PMA-stimulated StAR expression and progesterone synthesis. Transrepression of the StAR gene by DAX-1 was tightly associated with expression of the nuclear receptors Nur77 and steroidogenic factor-1, demonstrating these factors negatively modulate the steroidogenic response. These findings provide insight into the molecular events by which DAX-1 influences the PKA and PKC signaling pathways involved in the regulation of the StAR protein and steroidogenesis in mouse Leydig tumor cells. The characterization of protein kinase A- and protein kinase C-mediated steroidogenic acute regulatory (StAR) expression and steroidogenesis suggests that the orphan nuclear receptor DAX-1 is an important regulator of the steroidogenic response in Leydig cells.

cAMP-positive regulation of angiotensinogen gene expression and protein secretion in rat adipose tissue

2004 ◽  
Vol 286 (3) ◽  
pp. E434-E438 ◽  
Author(s):  
Valérie Serazin ◽  
Marie-Noelle Dieudonné ◽  
Mireille Morot ◽  
Philippe de Mazancourt ◽  
Yves Giudicelli
Keyword(s):  
Adipose Tissue ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Protein Secretion ◽  
Intracellular Camp ◽  
Pathological State ◽  
Mrna Levels ◽  
Adrenergic Stimulation ◽  
Rat Adipose Tissue ◽  
Kinase A

The adipose renin-angiotensin system (RAS) has been assigned to participate in the control of adipose tissue development and in the pathogenesis of obesity-related hypertension. In adipose cells, the biological responses to β-adrenergic stimulation are mediated by an increase in intracellular cAMP. Because cAMP is known to promote adipogenesis and because an association exists between body fat mass, hypertension, and increased sympathetic stimulation, we examined the influence of cAMP on angiotensinogen (ATG) expression and secretion in rat adipose tissue. Exposure of primary cultured differentiated preadipocytes to the cAMP analog 8-bromoadenosine 3′,5′-cyclic monophosphate (8-BrcAMP) or cAMP-stimulating agents (forskolin and IBMX) results in a significant increase in ATG mRNA levels. In adipose tissue fragments, 8-BrcAMP also increases ATG mRNA levels and protein secretion, but not in the presence of the protein kinase A inhibitor H89. The addition of isoproterenol, known to stimulate the synthesis of intracellular cAMP via β-adrenoreceptors, had the same stimulatory effect on ATG expression and secretion. These results indicate that cAMP in vitro upregulates ATG expression and secretion in rat adipose tissue via the protein kinase A-dependent pathway. Further studies are required to determine whether this regulatory pathway is activated in human obesity, where increased sympathetic tone is frequently observed, and to elucidate the importance of adipose ATG to the elevated blood pressure observed in this pathological state.

scholarly journals Brain Region Specific Alterations in the Protein and mRNA Levels of Protein Kinase A Subunits in the Post-Mortem Brain of Teenage Suicide Victims

2005 ◽  
Vol 30 (8) ◽  
pp. 1548-1556 ◽  
Author(s):  
Ghanshyam N Pandey ◽  
Yogesh Dwivedi ◽  
Xinguo Ren ◽  
Hooriyah S Rizavi ◽  
Amal C Mondal ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Brain Region ◽  
Mrna Levels ◽  
Post Mortem ◽  
Post Mortem Brain ◽  
Teenage Suicide ◽  
Kinase A

scholarly journals Genetic Analysis of the Kinetochore DASH Complex Reveals an Antagonistic Relationship with the Ras/Protein Kinase A Pathway and a Novel Subunit Required for Ask1 Association

2005 ◽  
Vol 25 (2) ◽  
pp. 767-778 ◽  
Author(s):  
Ju-mei Li ◽  
Yumei Li ◽  
Stephen J. Elledge
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Chromosome Segregation ◽  
Biochemical Analysis ◽  
Genetic Interaction ◽  
Negative Regulator ◽  
Ras Protein ◽  
Sister Chromatids ◽  
Pka Pathway ◽  
Kinase A

ABSTRACT DASH is a microtubule- and kinetochore-associated complex required for proper chromosome segregation and bipolar attachment of sister chromatids on the mitotic spindle. We have undertaken a genetic and biochemical analysis of the DASH complex and uncovered a strong genetic interaction of DASH with the Ras/protein kinase A (PKA) pathway. Overexpression of PDE2 or deletion of RAS2 rescued the temperature sensitivity of ask1-3 mutants. Ras2 negatively regulates DASH through the PKA pathway. Constitutive PKA activity caused by mutation of the negative regulator BCY1 is toxic to DASH mutants such as ask1 and dam1. In addition, we have discovered two novel subunits of DASH, Hsk2 and Hsk3 (helper of Ask1), which are microproteins of fewer than 75 amino acids, as dosage suppressors of ask1 mutants. These are essential genes that colocalize with DASH components on spindles and kinetochores and are present in the DASH complex. Mutants in hsk3 arrest cells in mitosis with short spindles and broken spindle structures characteristic of other DASH mutants. Hsk3 is critical for the integrity of the DASH complex because in hsk3 mutants the association of Dam1, Duo1, Spc34, and Spc19 with Ask1 is greatly diminished. We propose that Hsk3 acts to incorporate Ask1 into the DASH complex.

Transcript of protein kinase A knock-down modulates feeding behavior and neuropeptide Y gene expression in phenylpropanolamine-treated rats

2007 ◽  
Vol 31 (2) ◽  
pp. 306-314 ◽  
Author(s):  
Yih-Shou Hsieh ◽  
Shun-Fa Yang ◽  
Shu-Chen Chu ◽  
Dong-Yih Kuo
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Neuropeptide Y ◽  
Protein Kinase A ◽  
Mrna Level ◽  
Camp Response Element Binding ◽  
Antisense Oligodeoxynucleotide ◽  
Mrna Levels ◽  
Knock Down ◽  
Kinase A

Neuropeptide Y (NPY) is an appetite-controlling neuromodulator that contributes to the appetite-suppressing effect of phenylpropanolamine (PPA). Aims of this study were to investigate whether protein kinase A (PKA) signaling is involved in regulating NPY gene expression and PPA-induced anorexia. Rats were given daily with PPA for 5 days. Changes in daily food intake and hypothalamic NPY, PKA, cAMP response element binding protein (CREB), and pro-opiomelanocortin (POMC) gene expression were measured and compared. To further determine if PKA was involved, intracerebroventricular infusions of antisense oligodeoxynucleotide were performed at 60 min before daily PPA treatment in freely moving rats. Results showed that daily PKA, CREB, and POMC expression were increased following PPA treatment, which showed a closely reverse relationship with alterations of decreased feeding behaviors and NPY mRNA levels. Results also showed that PKA knock-down could block PPA-induced anorexia as well as restore NPY mRNA level, indicating the involvement of PKA signaling in the regulation of NPY gene expression. It is suggested that hypothalamic PKA signaling may participate in the central regulation of PPA-mediated appetite suppression via the modulation of hypothalamic NPY gene expression. The present findings reveal that manipulations at the molecular level of PKA or cAMP may allow the development of therapeutic agents to improve the undesirable properties of PPA or other amphetamine-like anorectic drugs.

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