scholarly journals TIMAP is a positive regulator of pulmonary endothelial barrier function

2008 ◽  
Vol 295 (3) ◽  
pp. L440-L450 ◽  
Author(s):  
Csilla Csortos ◽  
Istvan Czikora ◽  
Natalia V. Bogatcheva ◽  
Djanybek M. Adyshev ◽  
Christophe Poirier ◽  
...  
Keyword(s):  
Protective Role ◽  
Immunofluorescent Staining ◽  
Regulatory Subunit ◽  
Cell Periphery ◽  
Myosin Phosphatase ◽  
Regulatory Subunits ◽  
Sphingosine 1 Phosphate ◽  
Functional Complex ◽  
Interfering Rna

TGF-β-inhibited membrane-associated protein, TIMAP, is expressed at high levels in endothelial cells (EC). It is regarded as a member of the MYPT (myosin phosphatase target subunit) family of protein phosphatase 1 (PP1) regulatory subunits; however, its function in EC is not clear. In our pull-down experiments, recombinant TIMAP binds preferentially the β-isoform of the catalytic subunit of PP1 (PP1cβ) from pulmonary artery EC. As PP1cβ, but not PP1cα, binds with MYPT1 into functional complex, these results suggest that TIMAP is a novel regulatory subunit of myosin phosphatase in EC. TIMAP depletion by small interfering RNA (siRNA) technique attenuates increases in transendothelial electrical resistance induced by EC barrier-protective agents (sphingosine-1-phosphate, ATP) and enhances the effect of barrier-compromising agents (thrombin, nocodazole) demonstrating a barrier-protective role of TIMAP in EC. Immunofluorescent staining revealed colocalization of TIMAP with membrane/cytoskeletal protein, moesin. Moreover, TIMAP coimmunoprecipitates with moesin suggesting the involvement of TIMAP/moesin interaction in TIMAP-mediated EC barrier enhancement. Activation of cAMP/PKA cascade by forskolin, which has a barrier-protective effect against thrombin-induced EC permeability, attenuates thrombin-induced phosphorylation of moesin at the cell periphery of control siRNA-treated EC. On the contrary, in TIMAP-depleted EC, forskolin failed to affect the level of moesin phosphorylation at the cell edges. These results suggest the involvement of TIMAP in PKA-mediated moesin dephosphorylation and the importance of this dephosphorylation in TIMAP-mediated EC barrier protection.

scholarly journals PRKAR2A deficiency protects mice from experimental colitis by increasing IFN-stimulated gene expression and modulating the intestinal microbiota

2021 ◽  
Author(s):  
Lumin Wei ◽  
Rongjing Zhang ◽  
Jinzhao Zhang ◽  
Juanjuan Li ◽  
Deping Kong ◽  
...  
Keyword(s):  
Experimental Colitis ◽  
Regulatory Subunit ◽  
Protective Effects ◽  
Intestinal Epithelial ◽  
Catalytic Subunits ◽  
Regulatory Subunits ◽  
Pka Regulatory Subunit ◽  
Cross Fostering ◽  
Specific Deletion

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.

scholarly journals The protective role of sphingosine-1-phosphate against the action of the vascular disrupting agent combretastatin A-4 3-O-phosphate

Oncotarget ◽  
2017 ◽  
Vol 8 (56) ◽  
pp. 95648-95661 ◽  
Author(s):  
Joanna Shepherd ◽  
Matthew Fisher ◽  
Abigail Welford ◽  
Donald M. McDonald ◽  
Chryso Kanthou ◽  
...  
Keyword(s):  
Protective Role ◽  
Vascular Disrupting Agent ◽  
Sphingosine 1 Phosphate ◽  
Vascular Disrupting

scholarly journals The Role of Protein Phosphatase 2A Catalytic Subunit Cα in Embryogenesis: Evidence from Sequence Analysis and Localization Studies

1999 ◽  
Vol 380 (9) ◽  
pp. 1117-1120 ◽  
Author(s):  
Jürgen Götz ◽  
Wilfried Kues
Keyword(s):  
Protein Phosphatase ◽  
Genomic Organization ◽  
Protein Phosphatase 2A ◽  
Catalytic Subunit ◽  
Regulatory Subunit ◽  
Catalytic Subunits ◽  
Regulatory Subunits ◽  
Phosphatase 2A ◽  
The Brain

AbstractProtein phosphatase 2A (PP2A) constitutes one of the major families of protein serine/threonine phosphatases found in all eukaryotic cells. PP2A holoenzymes are composed of a catalytic subunit complexed with a structural regulatory subunit of 65 kDa. These core subunits associate with regulatory subunits of various sizes to form different heterotrimers which have been purified and evaluated with regard to substrate specificity. In fully differentiated tissues PP2A expression levels are highest in the brain, however, relatively little is known about expression in the developing embryo.In order to determine the composition of PP2A catalytic subunits in the mouse, cDNAs were cloned and the genomic organization of PP2A Cα was determined.By a gene targeting approach in the mouse, we have previously shown that the absence of the major catalytic subunit of PP2A, Cα, resulted in embryonic lethality around embryonic day E6.5. No mesoderm was formed which implied that PP2A plays a crucial role in gastrulation.Here, we extended our studies and analyzed wildtype embryos for Cα expression at subsequent stages of development. After gastrulation is completed, we find high expression of Cα restricted to the neural folds, which suggests that PP2A plays an additional pivotal role in neurulation.

scholarly journals Quantitative kinase and phosphatase profiling reveal that CDK1 phosphorylates PP2Ac to promote mitotic entry

2020 ◽  
Vol 13 (648) ◽  
pp. eaba7823 ◽  
Author(s):  
Isha Nasa ◽  
Lauren E. Cressey ◽  
Thomas Kruse ◽  
Emil P. T. Hertz ◽  
Jiang Gui ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Regulatory Subunit ◽  
Reciprocal Regulation ◽  
Chemical Proteomics ◽  
Catalytic Subunits ◽  
Regulatory Subunits ◽  
Mitotic Entry ◽  
Proteomics Approach ◽  
And Control

The reciprocal regulation of phosphoprotein phosphatases (PPPs) by protein kinases is essential to cell cycle progression and control, particularly during mitosis for which the role of kinases has been extensively studied. PPPs perform much of the serine/threonine dephosphorylation in eukaryotic cells and achieve substrate selectivity and specificity through the interaction of distinct regulatory subunits with conserved catalytic subunits in holoenzyme complexes. Using a mass spectrometry–based chemical proteomics approach to enrich, identify, and quantify endogenous PPP holoenzyme complexes combined with kinase profiling, we investigated the phosphorylation-dependent regulation of PPP holoenzymes in mitotic cells. We found that cyclin-dependent kinase 1 (CDK1) phosphorylated a threonine residue on the catalytic subunit of the phosphatase PP2A, which disrupted its holoenzyme formation with the regulatory subunit B55. The consequent decrease in the dephosphorylation of PP2A-B55 substrates promoted mitotic entry. This direct phosphorylation by CDK1 was in addition to a previously reported indirect mechanism, thus adding a layer to the interaction between CDK1 and PP2A in regulating mitotic entry.

scholarly journals S1P induces FA remodeling in human pulmonary endothelial cells: role of Rac, GIT1, FAK, and paxillin

2003 ◽  
Vol 94 (3) ◽  
pp. 1193-1203 ◽  
Author(s):  
Yasushi Shikata ◽  
Konstantin G. Birukov ◽  
Joe G. N. Garcia
Keyword(s):  
Focal Adhesions ◽  
Fiber Formation ◽  
Cell Periphery ◽  
Cortical Actin ◽  
Rac Gtpase ◽  
Actin Ring ◽  
Attachment Sites ◽  
Sphingosine 1 Phosphate ◽  
Gtpase Activation

Sphingosine 1-phosphate (S1P) enhances human pulmonary endothelial monolayer integrity via Rac GTPase-dependent formation of a cortical actin ring (Garcia et al. J Clin Invest 108: 689–701, 2001). The mechanisms underlying this response are not well understood but may involve rapid redistribution of focal adhesions (FA) as attachment sites for actin filaments. We evaluate the effects of S1P on the redistribution of paxillin, FA kinase (FAK), and the G protein-coupled receptor kinase-interacting proteins (GITs). S1P induced Rac GTPase activation and cortical actin ring formation at physiological concentrations (0.5 μM), whereas 5 μM S1P caused prominent stress fiber formation and activation of Rho and Rac GTPases. S1P (0.5 μM) stimulated the tyrosine phosphorylation of FAK Y576, and paxillin was linked to FA disruption and redistribution to the cell periphery. Furthermore, S1P induced a transient association of GIT1 with paxillin and redistribution of the GIT2-paxillin complex to the cell cortical area without affecting GIT2-paxillin association. These results suggest a role of FA rearrangement in S1P-mediated barrier enhancement via Rac- and GIT-mediated processes.

Small Molecule CDK Inhibitors for the Therapeutic Management of Cancer

2020 ◽  
Vol 20 (17) ◽  
pp. 1535-1563 ◽  
Author(s):  
Bharat Goel ◽  
Nancy Tripathi ◽  
Nivedita Bhardwaj ◽  
Shreyans K. Jain
Keyword(s):  
Cell Cycle ◽  
Regulatory Subunit ◽  
Cdk Inhibitors ◽  
Primary Role ◽  
Regulatory Subunits ◽  
Protein Substrates ◽  
Anti Cancer ◽  
Multifunctional Enzymes ◽  
Inhibitor Genes

: Cyclin-dependent kinases (CDKs) are a group of multifunctional enzymes consisting of catalytic and regulatory subunits. The regulatory subunit, cyclin, remains dissociated under normal circumstances, and complexation of cyclin with the catalytic subunit of CDK leads to its activation for phosphorylation of protein substrates. The primary role of CDKs is in the regulation of the cell cycle. Retinoblastoma protein (Rb) is one of the widely investigated tumor suppressor protein substrates of CDK, which prevents cells from entering into cell-cycle under normal conditions. Phosphorylation of Rb by CDKs causes its inactivation and ultimately allows cells to enter a new cell cycle. Many cancers are associated with hyperactivation of CDKs as a result of mutation of the CDK genes or CDK inhibitor genes. Therefore, CDK modulators are of great interest to explore as novel therapeutic agents against cancer and led to the discovery of several CDK inhibitors to clinics. This review focuses on the current progress and development of anti-cancer CDK inhibitors from preclinical to clinical and synthetic to natural small molecules.

scholarly journals The N-terminal 34 residues of the 55 kDa regulatory subunits of phosphoinositide 3-kinase interact with tubulin

2000 ◽  
Vol 346 (2) ◽  
pp. 483-489 ◽  
Author(s):  
Kouichi INUKAI ◽  
Makoto FUNAKI ◽  
Masao NAWANO ◽  
Hideki KATAGIRI ◽  
Takehide OGIHARA ◽  
...  
Keyword(s):  
Rat Brain ◽  
Kinase Activity ◽  
Protein Sequencing ◽  
Microtubule Assembly ◽  
Regulatory Subunit ◽  
Cell Periphery ◽  
Regulatory Subunits ◽  
Cell Extracts ◽  
Subunit Isoforms ◽  
Phosphoinositide 3 Kinase

There are five regulatory subunit isoforms of phosphoinositide 3-kinase (PI 3-kinase), which are classified into three groups: proteins of 85 kDa (p85α and p85β), 55 kDa (p55α and p55γ) and 50 kDa (p50α). Structural differences between the three groups reside in the N-terminus. To elucidate the unique functional role of the 55 kDa regulatory subunits, GST (glutathione S-transferase) fusion proteins containing a unique N-terminal portion consisting of a 34-amino-acid sequence of p55α or p55γ (GST-p55α/γN1-34) were used as affinity matrices to screen rat brain cell extracts for proteins to which this portion binds specifically. A protein that bound was identified as β-tubulin by protein sequencing. In addition, not only the β isoform of tubulin, but also the α and γ isoforms, were detected in the protein absorbed from cell lysates with GST-p55γN1-34 and GST-p55αN1-34 by immunoblotting. Indeed, the only regulatory subunit present in the purified microtubule assembly from rat brain was the 55 kDa isoform; neither 85 kDa nor 50 kDa subunits were detected. These results indicate endogenous binding of 55 kDa regulatory subunits of PI 3-kinase to tubulin in the brain. Finally, we measured tubulin-associated PI 3-kinase activity in CHO/IR cells overexpressing each of the five regulatory subunit isoforms. Only in cells expressing p55α or p55γ was there a significant elevation of tubulin-associated PI 3-kinase activity in response to insulin. These results suggest that the p55α and p55γ regulatory subunits have important roles in regulating PI 3-kinase activity, particularly for microtubules at the cell periphery.

Protective role of peroxiredoxin-4 in heart failure

2020 ◽  
Vol 134 (1) ◽  
pp. 71-72
Author(s):  
Naseer Ahmed ◽  
Masooma Naseem ◽  
Javeria Farooq
Keyword(s):  
Heart Failure ◽  
Cardiac Fibroblasts ◽  
Protective Role ◽  
Oxidative Stress Markers ◽  
Stress Markers ◽  
Total Antioxidant ◽  
Galectin 3 ◽  
Consequent Increase ◽  
And Oxidative Stress

Abstract Recently, we have read with great interest the article published by Ibarrola et al. (Clin. Sci. (Lond.) (2018) 132, 1471–1485), which used proteomics and immunodetection methods to show that Galectin-3 (Gal-3) down-regulated the antioxidant peroxiredoxin-4 (Prx-4) in cardiac fibroblasts. Authors concluded that ‘antioxidant activity of Prx-4 had been identified as a protein down-regulated by Gal-3. Moreover, Gal-3 induced a decrease in total antioxidant capacity which resulted in a consequent increase in peroxide levels and oxidative stress markers in cardiac fibroblasts.’ We would like to point out some results stated in the article that need further investigation and more detailed discussion to clarify certain factors involved in the protective role of Prx-4 in heart failure.

Parenting Behaviors and Anxiety in Young Adults

2015 ◽  
Vol 36 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Erin N. Stevens ◽  
Joseph R. Bardeen ◽  
Kyle W. Murdock
Keyword(s):  
Effortful Control ◽  
Parenting Behaviors ◽  
Protective Role ◽  
Anxiety Symptoms ◽  
Interactive Effects ◽  
Parental Overprotection ◽  
High Control ◽  
Development Of Anxiety ◽  
The Relationship

Parenting behaviors – specifically behaviors characterized by high control, intrusiveness, rejection, and overprotection – and effortful control have each been implicated in the development of anxiety pathology. However, little research has examined the protective role of effortful control in the relation between parenting and anxiety symptoms, specifically among adults. Thus, we sought to explore the unique and interactive effects of parenting and effortful control on anxiety among adults (N = 162). Results suggest that effortful control uniquely contributes to anxiety symptoms above and beyond that of any parenting behavior. Furthermore, effortful control acted as a moderator of the relationship between parental overprotection and anxiety, such that overprotection is associated with anxiety only in individuals with lower levels of effortful control. Implications for potential prevention and intervention efforts which specifically target effortful control are discussed. These findings underscore the importance of considering individual differences in self-regulatory abilities when examining associations between putative early-life risk factors, such as parenting, and anxiety symptoms.

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