scholarly journals Phosphorylation of H,K-ATPase α-Subunit in Microsomes from Rabbit Gastric Mucosa by cAMP-Dependent Protein Kinase

1999 ◽  
Vol 19 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Dilyara A. Murtazina ◽  
Sergei P. Petukhov ◽  
Kenneth B. Storey ◽  
Alexander M. Rubtsov ◽  
Olga D. Lopina
Keyword(s):  
Protein Kinase ◽  
Gastric Mucosa ◽  
Electrophoretic Mobility ◽  
Microsomal Fraction ◽  
Dependent Protein Kinase ◽  
Α Subunit ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Main Component ◽  
Triton X

A 100-kDa protein that is a main component of the microsomal fraction from rabbit gastric mucosa is phosphorylated by cAMP-dependent protein kinase (PKA) in the presence of 0.2% Triton X-100. Microsomes from rabbit gastric mucosa possess activity of H,K-ATPase but not activity of Na,K-ATPase. Incubation of microsomes with 5 μM fluorescein 5′-isothiocyanate (FITC) results in both an inhibition of H,K-ATPase and labeling of a protein with an electrophoretic mobility corresponding to the mobility of the protein phosphorylated by PKA. The data suggest that the α-subunit of H,K-ATPase can be a potential target for PKA phosphorylation.

scholarly journals Genetic Involvement of a cAMP-Dependent Protein Kinase in a G Protein Signaling Pathway Regulating Morphological and Chemical Transitions in Aspergillus nidulans

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 591-600
Author(s):  
Kiminori Shimizu ◽  
Nancy P Keller
Keyword(s):  
Protein Kinase ◽  
Aspergillus Nidulans ◽  
Signaling Pathway ◽  
G Protein ◽  
Radial Growth ◽  
Morphological Development ◽  
Dependent Protein Kinase ◽  
Α Subunit ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

Abstract In the filamentous fungus Aspergillus nidulans, a heterotrimeric G protein α-subunit and an RGS domain protein, encoded by fadA and flbA, respectively, regulate production of the carcinogenic metabolite sterigmatocystin (ST) and asexual spores (i.e., conidia). We investigated the genetic involvement of the cAMP-dependent protein kinase catalytic subunit (PkaA), a potential downstream target of FadA activity, in ST production and conidiation. Relative to wild type, sporulation was decreased in the pkaA overexpression strain but was not totally absent, as occurs in ΔflbA or fadAG42R (fadA-dominant active) strains. Deletion of pkaA resulted in a hyper-conidiating strain with limited radial growth. This phenotype was epistatic to mutation in flbA or fadA; the double mutants ΔpkaA; ΔflbA and ΔpkaA; fadAG42R recovered sporulation and their radial growth was severely restricted. PkaA overexpression also negatively regulated AflR, the ST biosynthesis-specific transcription factor, both transcriptionally and post-transcriptionally. Deletion of pkaA restored ST production in the ΔflbA background but not in the fadAG42R background. These data provide genetic evidence that the FlbA/FadA signaling pathway regulating ST production and morphological development is partially mediated through PkaA.

scholarly journals Negative Feedback Exerted by cAMP-dependent Protein Kinase and cAMP Phosphodiesterase on Subsarcolemmal cAMP Signals in Intact Cardiac Myocytes

2004 ◽  
Vol 279 (50) ◽  
pp. 52095-52105 ◽  
Author(s):  
Francesca Rochais ◽  
Grégoire Vandecasteele ◽  
Florence Lefebvre ◽  
Claire Lugnier ◽  
Hazel Lum ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Negative Feedback ◽  
Adrenergic Stimulation ◽  
Dependent Protein Kinase ◽  
Α Subunit ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Infected Cells ◽  
Camp Levels ◽  
Stimulation Of

Intracardiac cAMP levels are modulated by hormones and neuromediators with specific effects on contractility and metabolism. To understand how the same second messenger conveys different information, mutants of the rat olfactory cyclic nucleotide-gated (CNG) channel α-subunit CNGA2, encoded into adenoviruses, were used to monitor cAMP in adult rat ventricular myocytes. CNGA2 was not found in native myocytes but was strongly expressed in infected cells. In whole cell patch-clamp experiments, the forskolin analogue L-858051 (L-85) elicited a non-selective, Mg2+-sensitive current observed only in infected cells, which was thus identified as the CNG current (ICNG). The β-adrenergic agonist isoprenaline (ISO) also activatedICNG, although the maximal efficiency was ≈5 times lower than with L-85. However, ISO and L-85 exerted a similar maximal increase of the L-type Ca2+current. The use of a CNGA2 mutant with a higher sensitivity for cAMP indicated that this difference is caused by the activation of a localized fraction of CNG channels by ISO. cAMP-dependent protein kinase (PKA) blockade with H89 or PKI, or phosphodiesterase (PDE) inhibition with IBMX, dramatically potentiated ISO- and L-85-stimulatedICNG. A similar potentiation of β-adrenergic stimulation occurred when PDE4 was blocked, whereas PDE3 inhibition had a smaller effect (by 2-fold). ISO and L-85 increased total PDE3 and PDE4 activities in cardiomyocytes, although this effect was insensitive to H89. However, in the presence of IBMX, H89 had no effect on ISO stimulation ofICNG. This study demonstrates that subsarcolemmal cAMP levels are dynamically regulated by a negative feedback involving PKA stimulation of subsarcolemmal cAMP-PDE.

scholarly journals Evidence that cAMP-dependent protein kinase and a protein factor are involved in reactivation of triton X-100 models of sea urchin and starfish spermatozoa.

1982 ◽  
Vol 92 (3) ◽  
pp. 777-782 ◽  
Author(s):  
K Ishiguro ◽  
H Murofushi ◽  
H Sakai
Keyword(s):  
Protein Kinase ◽  
Sea Urchin ◽  
Kinase Inhibitor ◽  
Protein Kinase Inhibitor ◽  
Rabbit Muscle ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Protein Factor ◽  
Dependent Protein ◽  
Triton X

A fraction obtained from detergent-extract of sea urchin or starfish spermatozoa using DEAE-cellulose chromatography reactivated Triton X-100 models of the spermatozoa in a cAMP-dependent manner. The DEAE fraction contained cAMP-dependent protein kinase with a high level of specific activity. Rabbit muscle inhibitor protein highly specific for cAMP-dependent protein kinases inhibited the ability of the deae fraction to induce reactivation of Triton X-100 models.l This inhibition paralleled inhibition of cAMP-dependent protein kinase activity of the DEAE fraction, suggesting participation of the enzyme in the cAMP-dependent reactivation of Triton X-100 models. However, cAMP-dependent protein kinase further purified from the DEAE fraction was incapable of reactivating these models by itself. A protein factor which was separated from the protein kinase in the course of purification of the enzyme was found to also be necessary for the reactivation. When cAMP-dependent protein kinase was pretreated with protein kinase inhibitor before addition of the protein factor, the reactivation of Triton X-100 models was no longer detected. However, after the protein factor had been incubated with cAMP and cAMP-dependent protein kinase, protein kinase inhibitor did not repress reactivation of Triton X-100 models. We propose that the reactivation needs phosphorylation of the protein factor by cAMP-dependent protein kinase.

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