scholarly journals Protein Kinase A Catalytic Subunit Primed for Action: Time-Lapse Crystallography of Michaelis Complex Formation

Structure ◽  
2015 ◽  
Vol 23 (12) ◽  
pp. 2331-2340 ◽  
Author(s):  
Amit Das ◽  
Oksana Gerlits ◽  
Jerry M. Parks ◽  
Paul Langan ◽  
Andrey Kovalevsky ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Complex Formation ◽  
Protein Kinase A ◽  
Time Lapse ◽  
Catalytic Subunit ◽  
Action Time ◽  
Kinase A

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.

scholarly journals Meprin-β activity modulates the β-catalytic subunit of protein kinase A in ischemia-reperfusion-induced acute kidney injury

2020 ◽  
Vol 318 (5) ◽  
pp. F1147-F1159
Author(s):  
Faihaa Ahmed ◽  
Jean-Marie Mwiza ◽  
Mizpha Fernander ◽  
Ismaila Yahaya ◽  
Shaymaa Abousaad ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Signaling Pathway ◽  
Kinase Activity ◽  
Ischemia Reperfusion ◽  
Fluorescent Microscopy ◽  
Kidney Tissue ◽  
Kidney Injury ◽  
Catalytic Subunit ◽  
Kinase A

Meprin metalloproteases have been implicated in the progression of kidney injury. Previous work from our group has shown that meprins proteolytically process the catalytic subunit of protein kinase A (PKA-C), resulting in decreased PKA-C kinase activity. The goal of the present study was to determine the PKA-C isoforms impacted by meprin-β and whether meprin-β expression affects downstream mediators of the PKA signaling pathway in ischemia-reperfusion (IR)-induced kidney injury. IR was induced in 12-wk-old male wild-type (WT) and meprin-β knockout (βKO) mice. Madin-Darby canine kidney cells transfected with meprin-β cDNA were also subjected to 2 h of hypoxia. Western blot analysis was used to evaluate levels of total PKA-C, PKA-Cα, PKA-Cβ, phosphorylated (p-)PKA-C, and p-ERK1/2. Meprin-β expression enhanced kidney injury as indicated by levels of neutrophil gelatinase-associated lipocalin and cystatin C. IR-associated decreases were observed in levels of p-PKA-C in kidney tissue from WT mice but not βKO mice, suggesting that meprin-β expression/activity is responsible for the in vivo reduction in kinase activity. Significant increases in levels of PKA-Cβ were observed in kidney lysates for WT mice but not βKO mice at 6 h post-IR. Proximal tubule PKA-Cβ increases in WT but not βKO kidneys were demonstrated by fluorescent microscopy. Furthermore, IR-induced injury was associated with significant increases in p-ERK levels for both genotypes. The present data demonstrate that meprin-β enhances IR-induced kidney injury in part by modulating mediators of the PKA-Cβ signaling pathway.

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.

scholarly journals Candida albicans Lacking the Gene Encoding the Regulatory Subunit of Protein Kinase A Displays a Defect in Hyphal Formation and an Altered Localization of the Catalytic Subunit

2004 ◽  
Vol 3 (1) ◽  
pp. 190-199 ◽  
Author(s):  
Alejandro Cassola ◽  
Marc Parrot ◽  
Susana Silberstein ◽  
Beatrice B. Magee ◽  
Susana Passeron ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Protein Kinase ◽  
Fusion Protein ◽  
Protein Kinase A ◽  
Double Mutant ◽  
Catalytic Subunit ◽  
Regulatory Subunit ◽  
Wild Type ◽  
Gfp Fusion Protein ◽  
Kinase A

ABSTRACT The fungal pathogen Candida albicans switches from a yeast-like to a filamentous mode of growth in response to a variety of environmental conditions. We examined the morphogenetic behavior of C. albicans yeast cells lacking the BCY1 gene, which encodes the regulatory subunit of protein kinase A. We cloned the BCY1 gene and generated a bcy1 tpk2 double mutant strain because a homozygous bcy1 mutant in a wild-type genetic background could not be obtained. In the bcy1 tpk2 mutant, protein kinase A activity (due to the presence of the TPK1 gene) was cyclic AMP independent, indicating that the cells harbored an unregulated phosphotransferase activity. This mutant has constitutive protein kinase A activity and displayed a defective germinative phenotype in N-acetylglucosamine and in serum-containing medium. The subcellular localization of a Tpk1-green fluorescent protein (GFP) fusion protein was examined in wild-type, tpk2 null, and bcy1 tpk2 double mutant strains. The fusion protein was observed to be predominantly nuclear in wild-type and tpk2 strains. This was not the case in the bcy1 tpk2 double mutant, where it appeared dispersed throughout the cell. Coimmunoprecipitation of Bcy1p with the Tpk1-GFP fusion protein demonstrated the interaction of these proteins inside the cell. These results suggest that one of the roles of Bcy1p is to tether the protein kinase A catalytic subunit to the nucleus.

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