scholarly journals PRKAR1A gene analysis and protein kinase A activity in endometrial tumors

2012 ◽  
Vol 19 (4) ◽  
pp. 457-462 ◽  
Author(s):  
A Tsigginou ◽  
E Bimpaki ◽  
M Nesterova ◽  
A Horvath ◽  
S Boikos ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Subunit ◽  
Normal Endometrium ◽  
Protein Levels ◽  
Normal Tissues ◽  
Subunit Expression ◽  
Dependent Protein ◽  
Pka Regulatory Subunit ◽  
Kinase A

PRKAR1A codes for the type 1a regulatory subunit (RIα) of the cAMP-dependent protein kinase A (PKA), an enzyme with an important role in cell cycle regulation and proliferation. PKA dysregulation has been found in various tumors, and PRKAR1A-inactivating mutations have been reported in mostly endocrine neoplasias. In this study, we investigated PKA activity and the PRKAR1A gene in normal and tumor endometrium. Specimens were collected from 31 patients with endometrial cancer. We used as controls 41 samples of endometrium that were collected from surrounding normal tissues or from women undergoing gynecological operations for other reasons. In all samples, we sequenced the PRKAR1A-coding sequence and studied PKA subunit expression; we also determined PKA activity and cAMP binding. PRKAR1A mutations were not found. However, PKA regulatory subunit protein levels, both RIα and those of regulatory subunit type 2b (RIIβ), were lower in tumor samples; cAMP binding was also lower in tumors compared with normal endometrium (P<0.01). Free PKA activity was higher in tumor samples compared with that of control tissue (P<0.01). There are significant PKA enzymatic abnormalities in tumors of the endometrium compared with surrounding normal tissue; as these were not due to PRKAR1A mutations, other mechanisms affecting PKA function ought to be explored.

Stress-induced cytoplasmic localisation of the protein kinase A (PKA) regulatory subunit Bcy1 requires Sch9 and Yak1

2001 ◽  
Vol 1 (S1) ◽  
Author(s):  
G Griffioen ◽  
P Branduardi ◽  
B Ballarini ◽  
J Norbeck ◽  
B Baroni ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Regulatory Subunit ◽  
Pka Regulatory Subunit ◽  
Kinase A

scholarly journals Anchoring of Protein Kinase A-Regulatory Subunit IIα to Subapically Positioned Centrosomes Mediates Apical Bile Canalicular Lumen Development in Response to Oncostatin M but Not cAMP

2007 ◽  
Vol 18 (7) ◽  
pp. 2745-2754 ◽  
Author(s):  
Kacper A. Wojtal ◽  
Dick Hoekstra ◽  
Sven C.D. van IJzendoorn
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Membrane Trafficking ◽  
Oncostatin M ◽  
Regulatory Subunit ◽  
Apical Surface ◽  
Dependent Manner ◽  
Anchoring Protein ◽  
Pka Regulatory Subunit ◽  
Kinase A

Oncostatin M and cAMP signaling stimulate apical surface-directed membrane trafficking and apical lumen development in hepatocytes, both in a protein kinase A (PKA)-dependent manner. Here, we show that oncostatin M, but not cAMP, promotes the A-kinase anchoring protein (AKAP)-dependent anchoring of the PKA regulatory subunit (R)IIα to subapical centrosomes and that this requires extracellular signal-regulated kinase 2 activation. Stable expression of the RII-displacing peptide AKAP-IS, but not a scrambled peptide, inhibits the association of RIIα with centrosomal AKAPs and results in the repositioning of the centrosome from a subapical to a perinuclear location. Concomitantly, common endosomes, but not apical recycling endosomes, are repositioned from a subapical to a perinuclear location, without significant effects on constitutive or oncostatin M-stimulated basolateral-to-apical transcytosis. Importantly, however, the expression of the AKAP-IS peptide completely blocks oncostatin M-, but not cAMP-stimulated apical lumen development. Together, the data suggest that centrosomal anchoring of RIIα and the interrelated subapical positioning of these centrosomes is required for oncostatin M-, but not cAMP-mediated, bile canalicular lumen development in a manner that is uncoupled from oncostatin M-stimulated apical lumen-directed membrane trafficking. The results also imply that multiple PKA-mediated signaling pathways control apical lumen development and that subapical centrosome positioning is important in some of these pathways.

scholarly journals 17q22–24 Chromosomal Losses and Alterations of Protein Kinase A Subunit Expression and Activity in Adrenocorticotropin-Independent Macronodular Adrenal Hyperplasia

2006 ◽  
Vol 91 (9) ◽  
pp. 3626-3632 ◽  
Author(s):  
Isabelle Bourdeau ◽  
Ludmila Matyakhina ◽  
Sotirios G. Stergiopoulos ◽  
Fabiano Sandrini ◽  
Sosipatros Boikos ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Cushing Syndrome ◽  
Carney Complex ◽  
Chromosome 17 ◽  
Regulatory Subunit ◽  
Adrenal Tumors ◽  
Adrenal Hyperplasia ◽  
Subunit Expression ◽  
Kinase A

Abstract Context: Primary adrenocortical hyperplasias leading to Cushing syndrome include primary pigmented nodular adrenocortical disease and ACTH-independent macronodular adrenal hyperplasia (AIMAH). Inactivating mutations of the 17q22–24-located PRKAR1A gene, coding for the type 1A regulatory subunit of protein kinase A (PKA), cause primary pigmented nodular adrenocortical disease and the multiple endocrine neoplasia syndrome Carney complex. PRKAR1A mutations and 17q22–24 chromosomal losses have been found in sporadic adrenal tumors and are associated with aberrant PKA signaling. Objective: The objective of the study was to examine whether somatic 17q22–24 changes, PRKAR1A mutations, and/or PKA abnormalities are present in AIMAH. Patients: We studied fourteen patients with Cushing syndrome due to AIMAH. Methods: Fluorescent in situ hybridization with a PRKAR1A-specific probe was used for investigating chromosome 17 allelic losses. The PRKAR1A gene was sequenced in all samples, and tissue was studied for PKA activity, cAMP responsiveness, and PKA subunit expression. Results: We found 17q22–24 allelic losses in 73% of the samples. There were no PRKAR1A-coding sequence mutations. The RIIβ PKA subunit was overexpressed by mRNA, whereas the RIα, RIβ, RIIα, and Cα PKA subunits were underexpressed. These findings were confirmed by immunohistochemistry. Total PKA activity and free PKA activity were higher in AIMAH than normal adrenal glands, consistent with the up-regulation of the RIIβ PKA subunit. Conclusions: PRKAR1A mutations are not found in AIMAH. Somatic losses of the 17q22–24 region and PKA subunit and enzymatic activity changes show that PKA signaling is altered in AIMAH in a way that is similar to that of other adrenal tumors with 17q losses or PRKAR1A mutations.

scholarly journals Phosphorylation of protein kinase A (PKA) regulatory subunit RIα by protein kinase G (PKG) primes PKA for catalytic activity in cells

2018 ◽  
Vol 293 (12) ◽  
pp. 4411-4421 ◽  
Author(s):  
Kristofer J. Haushalter ◽  
Darren E. Casteel ◽  
Andrea Raffeiner ◽  
Eduard Stefan ◽  
Hemal H. Patel ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Protein Kinase G ◽  
Regulatory Subunit ◽  
Pka Regulatory Subunit ◽  
Kinase A ◽  
In Cells

scholarly journals Protein Kinase A Negatively Regulates Ca2+ signaling in Toxoplasma gondii

2018 ◽  
Author(s):  
Alessandro D. Uboldi ◽  
Mary-Louise Wilde ◽  
Emi A. McRae ◽  
Rebecca J. Stewart ◽  
Laura F. Dagley ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Host Cells ◽  
Regulatory Subunit ◽  
Supporting Evidence ◽  
New Paradigm ◽  
Apicomplexan Parasites ◽  
Intracellular Parasites ◽  
Dependent Protein ◽  
Kinase A

AbstractThe phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating forms and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is not understood. Here we show that the cAMP-dependent Protein Kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that that PKAc1 is sequestered to the parasite periphery by dual acylation of its regulatory subunit PKAr1. Newly invaded PKAc1-deficient parasites exit host cells shortly thereafter in a perforin-like protein 1 (PLP-1)-dependent fashion. We demonstrate that loss of PKAc1 results in an inability to rapidly downregulate cytosolic Ca2+ levels shortly after invasion. Furthermore, we demonstrate that PKAc1 also specifically negatively regulates resting cytosolic Ca2+ in conditions that mimic intracellularity. We also show that cAMP and cGMP have opposing role in microneme secretion, further supporting evidence that cAMP signalling has a suppressive role during motility. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity.

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