scholarly journals Cyclic AMP response element-binding protein and the catalytic subunit of protein kinase A are present in F9 embryonal carcinoma cells but are unable to activate the somatostatin promoter.

1992 ◽  
Vol 12 (3) ◽  
pp. 1096-1106 ◽  
Author(s):  
N Masson ◽  
M Ellis ◽  
S Goodbourn ◽  
K A Lee
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Protein Kinase A ◽  
Embryonal Carcinoma ◽  
Carcinoma Cells ◽  
Catalytic Subunit ◽  
Embryonal Carcinoma Cells ◽  
Undifferentiated Cells ◽  
F9 Embryonal Carcinoma Cells ◽  
Kinase A

The cyclic AMP (cAMP) response elements (CREs) of the somatostatin and vasoactive intestinal peptide (VIP) promoters contain binding sites for CRE-binding protein (CREB) that are essential for cAMP-regulated transcription. Using F9 embryonal carcinoma cells, we show that the somatostatin and VIP promoters exhibit a differentiation-dependent cAMP response, demonstrating that these promoters are regulated by transcription factors that become active during differentiation. Lack of cAMP responsiveness of the somatostatin promoter in undifferentiated cells is not due to the absence of known positive-acting factors (the catalytic subunit of protein kinase A [cPKA] and CREB) or a general inhibition of protein kinase A activity. Since overexpression of exogenous cPKA and CREB is sufficient to activate the somatostatin promoter in undifferentiated cells, these findings suggest that a negative factor(s) represses endogenous cPKA and CREB. In contrast to their effects on somatostatin, exogenous CREB and cPKA do not activate the VIP promoter. Thus, despite coregulation during differentiation and the ability to bind CREB, the somatostatin and VIP promoters are not coordinately activated by CREB in undifferentiated F9 cells.

Cyclic AMP response element-binding protein and the catalytic subunit of protein kinase A are present in F9 embryonal carcinoma cells but are unable to activate the somatostatin promoter

1992 ◽  
Vol 12 (3) ◽  
pp. 1096-1106
Author(s):  
N Masson ◽  
M Ellis ◽  
S Goodbourn ◽  
K A Lee
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Protein Kinase A ◽  
Embryonal Carcinoma ◽  
Carcinoma Cells ◽  
Catalytic Subunit ◽  
Embryonal Carcinoma Cells ◽  
Undifferentiated Cells ◽  
F9 Embryonal Carcinoma Cells ◽  
Kinase A

The cyclic AMP (cAMP) response elements (CREs) of the somatostatin and vasoactive intestinal peptide (VIP) promoters contain binding sites for CRE-binding protein (CREB) that are essential for cAMP-regulated transcription. Using F9 embryonal carcinoma cells, we show that the somatostatin and VIP promoters exhibit a differentiation-dependent cAMP response, demonstrating that these promoters are regulated by transcription factors that become active during differentiation. Lack of cAMP responsiveness of the somatostatin promoter in undifferentiated cells is not due to the absence of known positive-acting factors (the catalytic subunit of protein kinase A [cPKA] and CREB) or a general inhibition of protein kinase A activity. Since overexpression of exogenous cPKA and CREB is sufficient to activate the somatostatin promoter in undifferentiated cells, these findings suggest that a negative factor(s) represses endogenous cPKA and CREB. In contrast to their effects on somatostatin, exogenous CREB and cPKA do not activate the VIP promoter. Thus, despite coregulation during differentiation and the ability to bind CREB, the somatostatin and VIP promoters are not coordinately activated by CREB in undifferentiated F9 cells.

scholarly journals Coupling of hormonal stimulation and transcription via the cyclic AMP-responsive factor CREB is rate limited by nuclear entry of protein kinase A.

1993 ◽  
Vol 13 (8) ◽  
pp. 4852-4859 ◽  
Author(s):  
M Hagiwara ◽  
P Brindle ◽  
A Harootunian ◽  
R Armstrong ◽  
J Rivier ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Protein Kinase A ◽  
Cellular Responses ◽  
Catalytic Subunit ◽  
Nuclear Entry ◽  
Creb Phosphorylation ◽  
Eukaryotic Genes ◽  
C Subunit ◽  
Kinase A

Cyclic AMP (cAMP) regulates a number of eukaryotic genes by mediating the protein kinase A (PKA)-dependent phosphorylation of the CREB transcription factor at Ser-133. In this study, we test the hypothesis that the stoichiometry and kinetics of CREB phosphorylation are determined by the liberation and subsequent translocation of PKA catalytic subunit (C subunit) into the nucleus. Using fluorescence imaging techniques, we observed that PKA was activated in a stimulus-dependent fashion that led to nuclear entry of C subunit over a 30-min period. The degree of CREB phosphorylation, assessed with antiserum specific for CREB phosphorylated at Ser-133, correlated with the amount of PKA liberated. The time course of phosphorylation closely paralleled the nuclear entry of the catalytic subunit. There was a linear relationship between the subsequent induction of the cAMP-responsive somatostatin gene and the degree of CREB phosphorylation, suggesting that each event--kinase activation, CREB phosphorylation, and transcriptional induction--was tightly coupled to the next. In contrast to other PKA-mediated cellular responses which are rapid and quantitative, the slow, incremental regulation of CREB activity by cAMP suggests that multifunctional kinases like PKA may coordinate cellular responses by dictating the kinetics and stoichiometry of phosphorylation for key substrates like CREB.

Coupling of hormonal stimulation and transcription via the cyclic AMP-responsive factor CREB is rate limited by nuclear entry of protein kinase A

1993 ◽  
Vol 13 (8) ◽  
pp. 4852-4859
Author(s):  
M Hagiwara ◽  
P Brindle ◽  
A Harootunian ◽  
R Armstrong ◽  
J Rivier ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Protein Kinase A ◽  
Cellular Responses ◽  
Catalytic Subunit ◽  
Nuclear Entry ◽  
Creb Phosphorylation ◽  
Eukaryotic Genes ◽  
C Subunit ◽  
Kinase A

Cyclic AMP (cAMP) regulates a number of eukaryotic genes by mediating the protein kinase A (PKA)-dependent phosphorylation of the CREB transcription factor at Ser-133. In this study, we test the hypothesis that the stoichiometry and kinetics of CREB phosphorylation are determined by the liberation and subsequent translocation of PKA catalytic subunit (C subunit) into the nucleus. Using fluorescence imaging techniques, we observed that PKA was activated in a stimulus-dependent fashion that led to nuclear entry of C subunit over a 30-min period. The degree of CREB phosphorylation, assessed with antiserum specific for CREB phosphorylated at Ser-133, correlated with the amount of PKA liberated. The time course of phosphorylation closely paralleled the nuclear entry of the catalytic subunit. There was a linear relationship between the subsequent induction of the cAMP-responsive somatostatin gene and the degree of CREB phosphorylation, suggesting that each event--kinase activation, CREB phosphorylation, and transcriptional induction--was tightly coupled to the next. In contrast to other PKA-mediated cellular responses which are rapid and quantitative, the slow, incremental regulation of CREB activity by cAMP suggests that multifunctional kinases like PKA may coordinate cellular responses by dictating the kinetics and stoichiometry of phosphorylation for key substrates like CREB.

scholarly journals Activity, expression and function of a second Drosophila protein kinase A catalytic subunit gene.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1507-1520 ◽  
Author(s):  
A Meléndez ◽  
W Li ◽  
D Kalderon
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Essential Gene ◽  
Sequence Similarity ◽  
Catalytic Subunit ◽  
Subunit Gene ◽  
Drosophila Protein ◽  
Pka Catalytic Subunit ◽  
Kinase A

Abstract The DC2 gene was isolated previously on the basis of sequence similarity to DC0, the major Drosophila protein kinase A (PKA) catalytic subunit gene. We show here that the 67-kD Drosophila DC2 protein behaves as a PKA catalytic subunit in vitro. DC2 is transcribed in mesodermal anlagen of early embryos. This expression depends on dorsal but on neither twist nor snail activity. DC2 transcriptional fusions mimic this embryonic expression and are also expressed in subsets of cells in the optic lamina, wing disc and leg discs of third instar larvae. A saturation screen of a small deficiency interval containing DC2 for recessive lethal mutations yielded no DC2 alleles. We therefore isolated new deficiencies to generate deficiency trans-heterozygotes that lacked DC2 activity. These animals were viable and fertile. The absence of DC2 did not affect the viability or phenotype of imaginal disc cells lacking DC0 activity or embryonic hatching of animals with reduced DC0 activity. Furthermore, transgenes expressing DC2 from a DC0 promoter did not efficiently rescue a variety of DC0 mutant phenotypes. These observations indicate that DC2 is not an essential gene and is unlikely to be functionally redundant with DC0, which has multiple unique functions during development.

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