Phase Separation of a PKA Regulatory Subunit Controls cAMP Compartmentation and Oncogenic Signaling

AbstractProtein kinase A (PKA) plays an important role in regulating inflammation via its catalytic subunits. Recently, PKA regulatory subunits have been reported to directly modulate some signaling pathways and alleviate inflammation. However, the role of PKA regulatory subunits in colonic inflammation remains unclear. Therefore, we conducted this study to investigate the role of the PKA regulatory subunit PRKAR2A in colitis. We observed that PRKAR2A deficiency protected mice from dextran sulfate sodium (DSS)-induced experimental colitis. Our experiments revealed that the intestinal epithelial cell-specific deletion of Prkar2a contributed to this protection. Mechanistically, the loss of PRKAR2A in Prkar2a−/− mice resulted in an increased IFN-stimulated gene (ISG) expression and altered gut microbiota. Inhibition of ISGs partially reversed the protective effects against DSS-induced colitis in Prkar2a−/− mice. Antibiotic treatment and cross-fostering experiments demonstrated that the protection against DSS-induced colitis in Prkar2a−/− mice was largely dependent on the gut microflora. Altogether, our work demonstrates a previously unidentified function of PRKAR2A in promoting DSS-induced colitis.

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Multiple Interactions within the AKAP220 Signaling Complex Contribute to Protein Phosphatase 1 Regulation

Journal of Biological Chemistry ◽

10.1074/jbc.m010398200 ◽

2001 ◽

Vol 276 (15) ◽

pp. 12128-12134 ◽

Cited By ~ 41

Author(s):

Robynn V. Schillace ◽

James W. Voltz ◽

Alistair T. R. Sim ◽

Shirish Shenolikar ◽

John D. Scott

Keyword(s):

Intermolecular Interactions ◽

Protein Interactions ◽

Protein Phosphatase ◽

Competitive Inhibitor ◽

Regulatory Subunit ◽

Protein Protein Interactions ◽

Signaling Complex ◽

Activity Measurements ◽

Anchoring Protein ◽

Pka Regulatory Subunit

The phosphorylation status of cellular proteins is controlled by the opposing actions of protein kinases and phosphatases. Compartmentalization of these enzymes is critical for spatial and temporal control of these phosphorylation/dephosphorylation events. We previously reported that a 220-kDa A-kinase anchoring protein (AKAP220) coordinates the location of the cAMP-dependent protein kinase (PKA) and the type 1 protein phosphatase catalytic subunit (PP1c) (Schillace, R. V., and Scott, J. D. (1999)Curr. Biol.9, 321–324). We now demonstrate that an AKAP220 fragment is a competitive inhibitor of PP1c activity (Ki= 2.9 ± 0.7 μm). Mapping studies and activity measurements indicate that several protein-protein interactions act synergistically to inhibit PP1. A consensus targeting motif, between residues 1195 and 1198 (Lys-Val-Gln-Phe), binds but does not affect enzyme activity, whereas determinants between residues 1711 and 1901 inhibit the phosphatase. Analysis of truncated PP1c and chimeric PP1/2A catalytic subunits suggests that AKAP220 inhibits the phosphatase in a manner distinct from all known PP1 inhibitors and toxins. Intermolecular interactions within the AKAP220 signaling complex further contribute to PP1 inhibition as addition of the PKA regulatory subunit (RII) enhances phosphatase inhibition. These experiments indicate that regulation of PP1 activity by AKAP220 involves a complex network of intra- and intermolecular interactions.

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PKA Regulatory Subunit RIalpha Mixed-Backbone Antisense Oligonucleotide GEM 231

10.32388/ov5tdk ◽

2020 ◽

Author(s):

Keyword(s):

Antisense Oligonucleotide ◽

Regulatory Subunit ◽

Pka Regulatory Subunit

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AQP2 is a substrate for endogenous PP2B activity within an inner medullary AKAP-signaling complex

AJP Renal Physiology ◽

10.1152/ajprenal.2001.281.5.f958 ◽

2001 ◽

Vol 281 (5) ◽

pp. F958-F965 ◽

Cited By ~ 46

Author(s):

Inho Jo ◽

Donald T. Ward ◽

Michelle A. Baum ◽

John D. Scott ◽

Vincent M. Coghlan ◽

...

Keyword(s):

Hippocampal Neurons ◽

Collecting Duct ◽

Rat Kidney ◽

Regulatory Subunit ◽

Relative Molecular Mass ◽

Signaling Complex ◽

Anchoring Protein ◽

Pka Regulatory Subunit

We have demonstrated that inner medullary collecting duct (IMCD) heavy endosomes purified from rat kidney IMCD contain the type II protein kinase A (PKA) regulatory subunit (RII), protein phosphatase (PP)2B, PKCζ, and an RII-binding protein (relative molecular mass ∼90 kDa) representing a putative A kinase anchoring protein (AKAP). Affinity chromatography of detergent-solubilized endosomes on cAMP-agarose permits recovery of a protein complex consisting of the 90-kDa AKAP, RII, PP2B, and PKCζ. With the use of small-particle flow cytometry, RII and PKCζ were localized to an identical population of endosomes, suggesting that these proteins are components of an endosomal multiprotein complex.32P-labeled aquaporin-2 (AQP2) present in these PKA-phosphorylated endosomes was dephosphorylated in vitro by either addition of exogenous PP2B or by an endogenous endosomal phosphatase that was inhibited by the PP2B inhibitors EDTA and the cyclophilin-cyclosporin A complex. We conclude that IMCD heavy endosomes possess an AKAP multiprotein-signaling complex similar to that described previously in hippocampal neurons. This signaling complex potentially mediates the phosphorylation of AQP2 to regulate its trafficking into the IMCD apical membrane. In addition, the PP2B component of the AKAP-signaling complex could also dephosphorylate AQP2 in vivo.

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High expression of PKA regulatory subunit 1A protein is related to proliferation of human melanoma cells

Oncogene ◽

10.1038/sj.onc.1210831 ◽

2007 ◽

Vol 27 (13) ◽

pp. 1834-1843 ◽

Cited By ~ 28

Author(s):

G Mantovani ◽

S Bondioni ◽

A G Lania ◽

M Rodolfo ◽

E Peverelli ◽

...

Keyword(s):

Melanoma Cells ◽

Human Melanoma ◽

High Expression ◽

Regulatory Subunit ◽

Human Melanoma Cells ◽

Pka Regulatory Subunit

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Protein kinase A induces UCP1 expression in specific adipose depots to increase energy expenditure and improve metabolic health

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00114.2016 ◽

2016 ◽

Vol 311 (1) ◽

pp. R79-R88 ◽

Cited By ~ 17

Author(s):

Lorna M. Dickson ◽

Shriya Gandhi ◽

Brian T. Layden ◽

Ronald N. Cohen ◽

Barton Wicksteed

Keyword(s):

Adipose Tissue ◽

Energy Expenditure ◽

Cell Function ◽

Uncoupling Protein ◽

Metabolic Health ◽

Regulatory Subunit ◽

Increase Energy Expenditure ◽

Brown Adipose ◽

Β Cell Function ◽

Pka Regulatory Subunit

Adipose tissue PKA has roles in adipogenesis, lipolysis, and mitochondrial function. PKA transduces the cAMP signal downstream of G protein-coupled receptors, which are being explored for therapeutic manipulation to reduce obesity and improve metabolic health. This study aimed to determine the overall physiological consequences of PKA activation in adipose tissue. Mice expressing an activated PKA catalytic subunit in adipose tissue (Adipoq-caPKA mice) showed increased PKA activity in subcutaneous, epididymal, and mesenteric white adipose tissue (WAT) depots and brown adipose tissue (BAT) compared with controls. Adipoq-caPKA mice weaned onto a high-fat diet (HFD) or switched to the HFD at 26 wk of age were protected from diet-induced weight gain. Metabolic health was improved, with enhanced insulin sensitivity, glucose tolerance, and β-cell function. Adipose tissue health was improved, with smaller adipocyte size and reduced macrophage engulfment of adipocytes. Using metabolic cages, we found that Adipoq-caPKA mice were shown to have increased energy expenditure, but no difference to littermate controls in physical activity or food consumption. Immunoblotting of adipose tissue showed increased expression of uncoupling protein-1 (UCP1) in BAT and dramatic UCP1 induction in subcutaneous WAT, but no induction in the visceral depots. Feeding a HFD increased PKA activity in epididymal WAT of wild-type mice compared with chow, but did not change PKA activity in subcutaneous WAT or BAT. This was associated with changes in PKA regulatory subunit expression. This study shows that adipose tissue PKA activity is sufficient to increase energy expenditure and indicates that PKA is a beneficial target in metabolic health.

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

BMC News and views ◽

10.1186/2048-4623-1-s1-p011 ◽

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

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PRKAR1A gene analysis and protein kinase A activity in endometrial tumors

Endocrine Related Cancer ◽

10.1530/erc-11-0328 ◽

2012 ◽

Vol 19 (4) ◽

pp. 457-462 ◽

Cited By ~ 2

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.

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