• Journal of Life Science
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• v.18 no.9
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• pp.1219-1224
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• 2008

The embryonic zebrafish (Danio rerio) is rapidly becoming an important model organism for studies of early events in vertebrate development. Neural crest-derived pigment cell precursors of the embryonic zebrafish give rise to melanophores, xanthophores, and/or iridophores. Cell-signaling mechanisms related to the development of pigmentation and pigment pattern formation remain obscure. In this study, zebrafish embryos were treated with various signaling-related molecules - LiCl (an inositol-phosphatase inhibitor), forskolin (a protein kinase-A activator), a combination of LiCl/forskolin, and LiCl/heparin (an IP3 inhibitor) in order to identify the mechanisms involved in pigmentation. LiCl treatment resulted in ultrastructural and morphological alterations of melanophores. To identify the possible proteins responsible for this ultrastructural and morphological change, phosphorylation patterns in vitro and in vivo were analyzed. LiCl and LiCl/forskolin treatment elicited dramatic increases in the phosphorylation of a 55-kDa protein which was inhibited by heparin treatment. LiCl treatment also induced phosphorylation of a 55-kDa protein in melanophores purified from adult zebrafish. Collectively these results suggest that a LiCl-induced 55-kDa phosphoprotein plays a role in melanophore morphology and ultrastructure and ultimately effects gross pigmentation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.298-305
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• 2019

Cudrania tricuspidata has been reported to have many biological activities, including anti-inflammatory, anti-cancer, and antioxidant properties. However, the effects of C. tricuspidata root extract (CTE) on human platelet aggregation induced by collagen as well as the signaling pathways involved remain unknown. In the present study, we investigated the effect of CTE on human platelets. CTE inhibited platelet aggregation via down-regulation of thromboxane A₂ (TXA₂) by blocking cyclooxygenase-1 (COX-1) activity and intracellular Ca²⁺ mobilization in collagen-induced platelets. CTE also reduced the phosphorylation of phospholipase C (PLC) γ2 and syk. CTE regulated platelet aggregation via cyclic guanosine monophosphate (cGMP)-dependent phosphorylation of vasodilator-stimulated phosphoprotein (VASP) Ser²³⁹. In addition, administration of CTE (50 and 100 mg/kg) significantly reduced hyper-aggregated platelet aggregation by collagen (5 ㎍/mL) without hepatotoxicity in HFD (high fat diet)-fed rats. Taken together, these results suggest that CTE has anti-platelet effects both in vitro and in vivo. Therefore, CTE may be an effective therapeutic and preventive agent for cardiovascular disease, and is a safe and natural product.

• Journal of Ginseng Research
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• v.37 no.2
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• pp.176-186
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• 2013

In this study, we have investigated the effects of total saponin from Korean red ginseng (TSKRG) on thrombin-induced platelet aggregation. TSKRG dose-dependently inhibited thrombin-induced platelet aggregation with $IC_{50}$ value of about 81.1 ${\mu}g/mL$. In addition, TSKRG dose-dependently decreased thrombin-elevated the level of cytosolic-free $Ca^{2+}$ ($[Ca^{2+}]_i$), one of aggregation-inducing molecules. Of two $Ca^{2+}$-antagonistic cyclic nucleotides as aggregation-inhibiting molecules, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), TSKRG significantly dose-dependently elevated intracellular level of cAMP, but not cGMP. In addition, TSKRG dose-dependently inhibited thrombin-elevated adenosine triphosphate (ATP) release from platelets. These results suggest that the suppression of $[Ca^{2+}]_i$ elevation, and of ATP release by TSKRG are associated with upregulation of cAMP. TSKRG elevated the phosphorylation of vasodilator-stimulated phosphoprotein (VASP)-$Ser^{157}$, a cAMP-dependent protein kinase (A-kinase) substrate, but not the phosphorylation of VASP-$Ser^{239}$, a cGMP-dependent protein kinase substrate, in thrombin-activated platelets. We demonstrate that TSKRG involves in increase of cAMP level and subsequent elevation of VASP-$Ser^{157}$ phosphorylation through A-kinase activation to inhibit $[Ca^{2+}]_i$ mobilization and ATP release in thrombin-induced platelet aggregation. These results strongly indicate that TSKRG is a beneficial herbal substance elevating cAMP level in thrombin-platelet interaction, which may result in preventing of platelet aggregation-mediated thrombotic diseases.

• Childhood Kidney Diseases
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• v.10 no.1
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• pp.1-7
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• 2006

Osteopontin (OPN) is a glycosylated phosphoprotein which mediates cell adhesion and migration, and is produced by bone, macrophages, endothelial cells, and epithelial cells. The many regulatory functions of OPN include bone remodeling, tumor invasion, wound repair, and promotion of cell survival. It is produced by renal tubular epithelial cells, and expression is upregulated in glomerulonephritis, hypertension, ischemic acute renal failure, renal ablation, and UUO. In this review, we discuss about osteopontin in general aspect, expression, role on the development and pathologic condition of neonatal kidney.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.359-365
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• 2016

Background: Glycoprotein IIb/IIIa (${\alpha}aIIb/{\beta}_3$) is involved in platelet adhesion, and triggers a series of intracellular signaling cascades, leading to platelet shape change, granule secretion, and clot retraction. In this study, we evaluated the effect of ginsenoside Ro (G-Ro) on the binding of fibrinogen to ${\alpha}aIIb/{\beta}_3$. Methods: We investigated the effect of G-Ro on regulation of signaling molecules affecting the binding of fibrinogen to ${\alpha}aIIb/{\beta}_3$, and its final reaction, clot retraction. Results: We found that G-Ro dose-dependently inhibited thrombin-induced platelet aggregation and attenuated the binding of fibrinogen to ${\alpha}aIIb/{\beta}_3$ by phosphorylating cyclic adenosine monophosphate (cAMP)-dependently vasodilator-stimulated phosphoprotein (VASP; $Ser^{157}$). In addition, G-Ro strongly abrogated the clot retraction reflecting the intensification of thrombus. Conclusion: We demonstrate that G-Ro is a beneficial novel compound inhibiting ${\alpha}aIIb/{\beta}_3$-mediated fibrinogen binding, and may prevent platelet aggregation-mediated thrombotic disease.

• Biomolecules & Therapeutics
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• v.15 no.2
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• pp.78-82
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• 2007

The proto-oncogene protein DEK is a nuclear binding phosphoprotein that has been associated with various human diseases including leukemia. Histone acetylation is an important post-translational modification which plays important role in transcriptional regulation. Auto-acetylation of histone acetyltransferase PCAF results in increment of its HAT activity and facilitation of its nuclear localization. In this study, we report that DEK inhibits PCAF auto-acetylation through direct interaction. The C-terminal acidic domains of DEK are responsible for the interaction with PCAF. Using confocal microscopy, we have shown that nuclear localization of PCAF is severely inhibited by DEK. Taken together, our results suggest that DEK may be involved in various cellular signal transduction pathways accommodated by PCAF through the regulation of PCAF auto-acetylation.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.641-646
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• 1996

[$\gamma$-$^{32}$P]ATP was used to test phosphorylation of membrane proteins of mating type a cells of heterobasidiomycetous yeast Rhodosporidium toruloides separated by non-denaturing electrophoresis. The phosphoprotein was observed in the membrane proteins. The phosphorylation was inhibited by the pheromone rhodotorucine A (Rh. A) secreted by mating type A of the yeast. Rh. A didn't inhibit the phosphorylation in the presence of a trigger peptidase (TPase) inhibitor, antipain. Partially digested Rh. A by trypsin maintained the phosphorylation inhibitory activity. These results show that TPase activity plays an important role in the transduction of pheromone signal in the yeast.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.535-539
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• 2005

The thermoacidophilic archaeon Thermoplasma acidophilum has long been known to utilize D-glucose via the non-phosphorylated Entner-Doudoroff (nED) pathway. We now report the identification of a gene encoding 2-keto-3-deoxy-D-gluconate (KDG) kinase. The discovery of this gene implies the presence of a glycolysis pathway, other than the nED pathway. It was found that Ta0122 in the T. acidophilum genome corresponded to KDG kinase. This enzyme shares no similarity with known KDG kinases, and belongs to a novel class of sugar kinases. Of the five sugars tested only KDG was utilized as a substrate.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.122-128
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• 1992

Post-translational modifications of the nucleocapsid protein of bovine coronavirus (Quebec strain) were investigated. Coronavirions were radiolabelled in vivo with inorganic $[^{32}P]$orthophosphate and analysed by SDS-PAGE, followed by autoradiography. A single polypeptide with a migration rate of 55 KDa was identified by metabolic phosphate labelling, demonstrating that the nucleocapsid protein of bovine coronavirus was a phosphoprotein. A gene encoding the nucleocapsid protein was inserted immediately downstream from the polyhedrin promoter of Autographa californica nuclear polyhedrosis baculovirus. Spodoptera frugiperda cells infected with this recombinant baculovirus synthesized a 55 KDa polypeptide, as demonstrated by immunoprecipitation with anti-nucleocapsid monoclonal antibody. The recombinant nucleocapsid protein synthesized in Spodoptera cells could also be labelled by $[^{32}P]$orthophosphate. Phosphoamino acid analysis showed that both serine and threonine residues were phosphorylated in authentic, as well as in recombinant nucleocapsid proteins, with a relative phosphorylation ratio of 7:3. Our studies demonstrated that the nucleocapsid protein of bovine coronavirus was a serine and threonine-phosphorylated protein and that Spodoptera insect cells were able to properly phosphorylate the relevant foreign proteins.

• BMB Reports
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• v.41 no.12
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• pp.840-845
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• 2008

Nucleophosmin/B23, a major nucleolar phosphoprotein, is overexpressed in actively proliferating cells. In this study, we demonstrate that B23 exclusively localizes in the nucleolus, whereas ATP depletion results in the redistribution of B23 throughout the whole nucleus and destabilizes B23 via caspase-3 mediated cleavage. Interestingly, ATP binding precedes PI(3,4,5)P3 binding at lysine 263 and ATP binding mutants fail to restore the anti-apoptotic functions of B23 in PC12 cells. Thus, the ATP-B23 interaction is required for the stability of the B23 protein and regulates cell survival, confining B23 within the nucleolus in PC12 cells.