A novel activating effect of the regulatory subunit of protein kinase A on catalytic subunit activity

2008 ◽  
Vol 480 (2) ◽  
pp. 95-103 ◽  
Author(s):  
Jimena Rinaldi ◽  
Josefina Ocampo ◽  
Silvia Rossi ◽  
Silvia Moreno
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Catalytic Subunit ◽  
Regulatory Subunit ◽  
Kinase A

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.

scholarly journals Protein kinase A activation: Something new under the sun?

2018 ◽  
Vol 217 (6) ◽  
pp. 1895-1897 ◽  
Author(s):  
F. Donelson Smith ◽  
John D. Scott
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Active Site ◽  
Catalytic Subunit ◽  
Regulatory Subunit ◽  
The Sun ◽  
Type Ii ◽  
Activation Mechanisms ◽  
Kinase A

The role of autophosphorylation of the type II regulatory subunit in activation of protein kinase A (PKA) has been a longstanding question. In this issue, Isensee et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201708053) use antibody tools that selectively recognize phosphorylated RII and the catalytic subunit active site to reexamine PKA holoenzyme activation mechanisms in neurons.

scholarly journals Unidirectional allostery in the regulatory subunit RIα facilitates efficient deactivation of protein kinase A

2016 ◽  
Vol 113 (44) ◽  
pp. E6776-E6785 ◽  
Author(s):  
Cong Guo ◽  
Huan-Xiang Zhou
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Structural Similarity ◽  
Community Analysis ◽  
Catalytic Subunit ◽  
Regulatory Subunit ◽  
Allosteric Communication ◽  
Dynamics Simulations ◽  
A Site ◽  
Kinase A

The holoenzyme complex of protein kinase A is in an inactive state; activation involves ordered cAMP binding to two tandem domains of the regulatory subunit and release of the catalytic subunit. Deactivation has been less studied, during which the two cAMPs unbind from the regulatory subunit to allow association of the catalytic subunit to reform the holoenzyme complex. Unbinding of the cAMPs appears ordered as indicated by a large difference in unbinding rates from the two sites, but the cause has remained elusive given the structural similarity of the two tandem domains. Even more intriguingly, NMR data show that allosteric communication between the two domains is unidirectional. Here, we present a mechanism for the unidirectionality, developed from extensive molecular dynamics simulations of the tandem domains in different cAMP-bound forms. Disparate responses to cAMP releases from the two sites (A and B) in conformational flexibility and chemical shift perturbation confirmed unidirectional allosteric communication. Community analysis revealed that the A-site cAMP, by forming across-domain interactions, bridges an essential pathway for interdomain communication. The pathway is impaired when this cAMP is removed but remains intact when only the B-site cAMP is removed. Specifically, removal of the A-site cAMP leads to the separation of the two domains, creating room for binding the catalytic subunit. Moreover, the A-site cAMP, by maintaining interdomain coupling, retards the unbinding of the B-site cAMP and stalls an unproductive pathway of cAMP release. Our work expands the perspective on allostery and implicates functional importance for the directionality of allostery.

scholarly journals Targeting the Regulatory Subunit R2Alpha of Protein Kinase A in Human Glioblastoma through shRNA-Expressing Lentiviral Vectors

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1361
Author(s):  
Maira Zorzan ◽  
Claudia Del Vecchio ◽  
Stefania Vogiatzis ◽  
Elisa Saccon ◽  
Cristina Parolin ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Lentiviral Vectors ◽  
Brain Parenchyma ◽  
Regulatory Subunit ◽  
Glioblastoma Cells ◽  
Cellular Models ◽  
Therapeutic Setting ◽  
Promising Target ◽  
Kinase A

Glioblastoma is the most malignant and most common form of brain tumor, still today associated with a poor 14-months median survival from diagnosis. Protein kinase A, particularly its regulatory subunit R2Alpha, presents a typical intracellular distribution in glioblastoma cells compared to the healthy brain parenchyma and this peculiarity might be exploited in a therapeutic setting. In the present study, a third-generation lentiviral system for delivery of shRNA targeting the regulatory subunit R2Alpha of protein kinase A was developed. Generated lentiviral vectors are able to induce an efficient and stable downregulation of R2Alpha in different cellular models, including non-stem and stem-like glioblastoma cells. In addition, our data suggest a potential correlation between silencing of the regulatory subunit of protein kinase A and reduced viability of tumor cells, apparently due to a reduction in replication rate. Thus, our findings support the role of protein kinase A as a promising target for novel anti-glioma therapies.

The crystal structure of yeast regulatory subunit reveals key evolutionary insights into Protein Kinase A oligomerization

2021 ◽  
pp. 107732
Author(s):  
Nicolás González Bardeci ◽  
Enzo Tofolón ◽  
Felipe Trajtenberg ◽  
Julio Caramelo ◽  
Nicole Larrieux ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Subunit ◽  
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 The Role of Uncoupling Protein 1 in the Metabolism and Adiposity of RIIβ-Protein Kinase A-Deficient Mice

2004 ◽  
Vol 18 (9) ◽  
pp. 2302-2311 ◽  
Author(s):  
Michael A. Nolan ◽  
Maria A. Sikorski ◽  
G. Stanley McKnight
Keyword(s):  
Adipose Tissue ◽  
Oxygen Consumption ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Uncoupling Protein ◽  
Mrna Level ◽  
Regulatory Subunit ◽  
Uncoupling Protein 1 ◽  
Brown Adipose ◽  
Kinase A

Abstract Mice lacking the RIIβ regulatory subunit of protein kinase A exhibit a 50% reduction in white adipose tissue stores compared with wild-type littermates and are resistant to diet-induced obesity. RIIβ−/− mice also have an increase in resting oxygen consumption along with a 4-fold increase in the brown adipose-specific mitochondrial uncoupling protein 1 (UCP1). In this study, we examined the basis for UCP1 induction and tested the hypothesis that the induced levels of UCP1 in RIIβ null mice are essential for the lean phenotype. The induction of UCP1 occurred at the protein but not the mRNA level and correlated with an increase in mitochondria in brown adipose tissue. Mice lacking both RIIβ and UCP1 (RIIβ−/−/Ucp1−/−) were created, and the key parameters of metabolism and body composition were studied. We discovered that RIIβ−/− mice exhibit nocturnal hyperactivity in addition to the increased oxygen consumption at rest. Disruption of UCP1 in RIIβ−/− mice reduced basal oxygen consumption but did not prevent the nocturnal hyperactivity. The double knockout animals also retained the lean phenotype of the RIIβ null mice, demonstrating that induction of UCP1 and increased resting oxygen consumption is not the cause of leanness in the RIIβ mutant mice.

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