scholarly journals Alterations in Cyclic AMP Generation and G Protein Subunits following Transient Ischemia in Gerbil Hippocampus

1995 ◽  
Vol 15 (5) ◽  
pp. 877-885 ◽  
Author(s):  
Kazuhiko Suyama ◽  
Kuniaki Saito ◽  
Guang Chen ◽  
Bai-Shen Pan ◽  
Husseini K. Manji ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
G Protein ◽  
Neuronal Degeneration ◽  
Hippocampal Slices ◽  
Transient Ischemia ◽  
Dependent Protein Kinase ◽  
Protein Subunits ◽  
Dependent Protein ◽  
Generating System ◽  
Α Subunits

We examined alterations in the cyclic AMP generating system and G protein subunits in gerbil hippocampus following 10 min of transient ischemia. In hippocampal slices, basal and isoproterenol- and forskolin-stimulated cyclic AMP accumulations were markedly increased at 6 and 24 h after ischemia. Interestingly, both the inhibition of forskolin-stimulated cyclic AMP and the potentiation of β-adrenoceptor-stimulated cyclic AMP by a γ-aminobutyric acidB receptor agonist were attenuated at these time points. Ischemia did not affect the immuno-labeling of any of the G protein α subunits; only that of β subunits was significantly decreased, by 28.2%, 4 days after ischemia. In contrast, pertussis toxin-catalyzed [32P]ADP ribosylation declined progressively during the late recirculation period, reaching a significant reduction (25.4%) at 6 h after ischemia. These results suggest that ischemia affects the heterotrimeric conformation (αβγ) of Gi/Go during the recirculation period, thereby leading to increased cyclic AMP production. Because cyclic AMP-dependent protein kinase A modulates the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-kainate receptor channels, postischemic sensitization of the cyclic AMP generating system may contribute to neuronal degeneration in the hippocampus.

scholarly journals A cytosolic cyclic AMP-dependent protein kinase in Dictyostelium discoideum. I. Properties.

1984 ◽  
Vol 259 (1) ◽  
pp. 654-661 ◽  
Author(s):  
I H Majerfeld ◽  
B H Leichtling ◽  
J A Meligeni ◽  
E Spitz ◽  
H V Rickenberg
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Dependent Protein Kinase ◽  
Dependent Protein

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.

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