• Journal of Microbiology
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• v.43 no.6
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• pp.529-536
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• 2005

Viral infection causes stress to the endoplasmic reticulum (ER). The response to endoplasmic reticulum stress, known as the unfolded protein response (UPR), is designed to eliminate misfolded proteins and allow the cell to recover. The role of hepatitis C virus (HCV) non-structural protein NS4B, a component of the HCV replicons that induce UPR, is incompletely understood. We demonstrate that HCV NS4B could induce activating transcription factor (ATF6) and inositol-requiring enzyme 1 (IRE1), to favor the HCV subreplicon and HCV viral replication. HCV NS4B activated the IRE1 pathway, as indicated by splicing of X box-binding protein (Xbp-1) mRNA. However, transcriptional activation of the XBP-1 target gene, EDEM (ER degradation-enhancing $\alpha-mannosidase-like$ protein, a protein degradation factor), was inhibited. These results imply that NS4B might induce UPR through ATF6 and IRE1-XBP1 pathways, but might also modify the outcome to benefit HCV or HCV subreplicon replication.

• Biomolecules & Therapeutics
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• v.25 no.1
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• pp.12-25
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• 2017

G protein-coupled receptors (GPCRs) are a family of cell-surface proteins that play critical roles in regulating a variety of pathophysiological processes and thus are targeted by almost a third of currently available therapeutics. It was originally thought that GPCRs convert extracellular stimuli into intracellular signals through activating G proteins, whereas ${\beta}$-arrestins have important roles in internalization and desensitization of the receptor. Over the past decade, several novel functional aspects of ${\beta}$-arrestins in regulating GPCR signaling have been discovered. These previously unanticipated roles of ${\beta}$-arrestins to act as signal transducers and mediators of G protein-independent signaling have led to the concept of biased agonism. Biased GPCR ligands are able to engage with their target receptors in a manner that preferentially activates only G protein- or ${\beta}$-arrestin-mediated downstream signaling. This offers the potential for next generation drugs with high selectivity to therapeutically relevant GPCR signaling pathways. In this review, we provide a summary of the recent studies highlighting G protein- or ${\beta}$-arrestin-biased GPCR signaling and the effects of biased ligands on disease pathogenesis and regulation.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.780-786
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• 2002

An immunosensor based on surface plasmon resonance (SPR) with a self-assembled protein G layer was developed for the detection of Escherichia coli O157:H7. A self-assembled protein C layer on a gold (Au) surface was fabricated by adsorbing the mixture of 11-mercaptoundecanoic acid (MUA) and hexanethiol at various molar ratios and by activating chemical binding between free amine (-$NH_2$) of protein G and 11-(MUA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC) in series. The formation of a self-assembled protein G layer on an Au substrate and the binding of the antibody and antigen in series were confirmed by SPR spectroscopy. The surface morphology analyses of the self-assembled protein G layer on the Au substrate, monoclonal antibody (Mab) against E. coli O157:H7 which was immobilized on protein G, and bound E. coli O157:H7 extracts on Immobilized Mab against E. coii O157:H7 were performed by atomic force microscopy (AFM). The detection limit of the SPR-based immunosensor for E. coli O157:H7 was found to be about $10^4$ cells/ml.

• Development and Reproduction
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• v.22 no.1
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• pp.65-72
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• 2018

Cyclic AMP-response element binding protein zhangfei (CREBZF), a member of ATF/CREB (activating transcription factor/ cAMP response element binding protein) family, regulates numerous cellular functions and development of cells by interacting transcription factors. This study discovered the expression pattern of CREBZF in seminiferous tubule of testes during the postnatal development of mice. In testis, CREBZF mRNA expression was the highest among other organs. Immunofluorescence analyses showed that the CREBZF was specifically expressed on spermatocyte but not in spermatogonia and Sertoli cells in seminiferous epithelium of mouse testis. Semi-quantitative polymerase chain reaction (PCR) analysis showed that CREBZF transcript level was significantly elevated during postnatal development of mouse testis. Confocal imaging analysis indicated that the protein expression of CREBZF in seminiferous tubule remained low until postnatal day (PD) 14, and was dramatically increased in PD 21. Interestingly, only one type of the spermatocyte expressed CREBZF specifically among SCP3-positive spermatocytes. Taken together, these results suggest that CREBZF may be novel putative marker of the spermatocyte and regulate meiosis during postnatal development of mice.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.14-14
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• 2015

Fungi are of particular interest due to their capacity to produce an extensive array of secondary metabolites. While many secondary metabolites have no known functions to the producing fungal organisms, these metabolites have tremendous importance to humans with beneficial (e.g., antibiotics) or detrimental (e.g., mycotoxins) properties. In this study, two important filamentous fungi, Fusarium verticillioides and Mycosphaerella graminicola were selected as target species and the genes regulatory functions on the biosynthesis of secondary metabolisms were studied. Functional genomics including forward and reverse genetics, and proteomics were utilized to better understand the complex secondary metabolism regulations in both F. verticillioides and M. graminicola. Identified genes in either F. verticillioides or M. graminicola background were CPP1 (a putative protein phosphatase gene), GAC1 (encoding a GTPase activating protein), MCC1(encoding c-type cyclin), and the velvet gene, MVE1. Our data suggest that there are diverse regulatory genes on fungal secondary metabolites with distinct or overlapping functional roles.

• Journal of Microbiology
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• v.41 no.3
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• pp.266-270
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• 2003

Orientia tsutsugamushi, an obligate intracellular bacterium, is the causative agent of scrub typhus which is histopathologically characterized by inflammatory manifestations. To understand the pathogenesis of scrub typhus, chemokine gene expression in mice after infection with O. tsutsugamushi was investigated. The mRNAs that were upregulated included macrophage inflammatory proteins 1${\alpha}$/${\beta}$ (MIP-1${\alpha}$/${\beta}$), MIP-2, monocyte chemoattractant protein 1, RANTES (regulated upon activation, normal T-cell expressed and secreted), and gamma-interferon-inducible protein 10. Peak expression of these chemokines was observed six days after infection. These responses returned to or approached baseline preinfection levels by eight days after infection. Chemokine profiles in infected mice were well correlated with the kinetics of inflammatory cell infiltration. Thus, O. tsutsugamushi appears to be a strong inducer of chemokines which may significantly contribute to the inflammation observed in scrub typhus by attracting and activating phagocytic leukocytes.

• Journal of Veterinary Science
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• v.21 no.3
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• pp.50.1-50.16
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• 2020

Background: Porcine parvovirus (PPV) is a single-stranded DNA virus that causes porcine reproductive failure. It is of critical importance to study PPV pathogenesis for the prevention and control of the disease. NS1, a PPV non-structural protein, is participated in viral DNA replication, transcriptional regulation, and cytotoxicity. Our previous research showed that PPV can activate nuclear factor kappa B (NF-κB) signaling pathway and then up-regulate the expression of interleukin (IL)-6. Objectives: Herein, the purpose of this study is to determine whether the non-structural protein NS1 of PPV also has the same function. Methods: Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay, western blot, immunofluorescence assay and small interfering RNA (siRNA) were used. Results: Our findings demonstrated that PPV NS1 protein can up-regulate the expression levels of IL-6 and tumor necrosis factor-alpha in a dose-dependent manner. Moreover, PPV NS1 protein was found to induce the phosphorylation of IκBα, then leading to the phosphorylation and nuclear translocation of NF-κB. In addition, the NS1 protein activated the upstream pathways of NF-κB. Meanwhile, TLR2-siRNA assay showed TLR2 plays an important role in the activation of NF-κB signaling pathway induced by PPV-NS1. Conclusions: These findings indicated that PPV NS1 protein induced the up-regulated of IL-6 expression through activating the TLR2 and NF-κB signaling pathways. In conclusion, these findings provide a new avenue to study the innate immune mechanism of PPV infection.

• Biomolecules & Therapeutics
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• v.28 no.3
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• pp.259-266
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• 2020

The present research work primarily investigated whether spinosin has the potential of improving the pathogenesis of Alzheimer's disease (AD) driven by β-amyloid (Aβ) overproduction through impacting the procession of amyloid precursor protein (APP). Wild type mouse Neuro-2a cells (N2a/WT) and N2a stably expressing human APP695 (N2a/APP695) cells were treated with spinosin for 24 h. The levels of APP protein and secreted enzymes closely related to APP procession were examined by western blot analysis. Oxidative stress related proteins, such as nuclear factor-erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) were detected by immunofluorescence assay and western blot analysis, respectively. The intracellular reactive oxygen species (ROS) level was analyzed by flow cytometry, the levels of Aβ_1-42 were determined by ELISA kit, and Thioflavin T (ThT) assay was used to detect the effect of spinosin on Aβ_1-42 aggregation. The results showed that ROS induced the expression of ADAM10 and reduced the expression of BACE1, while spinosin inhibited ROS production by activating Nrf2 and up-regulating the expression of HO-1. Additionally, spinosin reduced Aβ_1-42 production by impacting the procession of APP. In addition, spinosin inhibited the aggregation of Aβ_1-42. In conclusion, spinosin reduced Aβ_1-42 production by activating the Nrf2/HO-1 pathway in N2a/WT and N2a/APP695 cells. Therefore, spinosin is expected to be a promising treatment of AD.

• Journal of Korean Neurosurgical Society
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• v.65 no.2
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• pp.236-244
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• 2022

Objective : To evaluate the interactions among differentially expressed autophagy and mitophagy markers in subarachnoid hemorrhage (SAH) patients with delayed cerebral ischemia (DCI). Methods : The expression data of autophagy and mitophagy-related makers in the cerebrospinal fluid (CSF) cells was analyzed by real-time reverse transcription-polymerase chain reaction and Western blotting. The markers included death-associated protein kinase (DAPK)-1, BCL2 interacting protein 3 like (BNIP3L), Bcl-1 antagonist X, phosphatase and tensin homolog-induced kinase (PINK), Unc-51 like autophagy activating kinase 1, nuclear dot protein 52, and p62. In silico functional analyses including gene ontology enrichment and the protein-protein interaction network were performed. Results : A total of 56 SAH patients were included and 22 (38.6%) of them experienced DCI. The DCI patients had significantly increased mRNA levels of DAPK1, BNIP3L, and PINK1, and increased expression of BECN1 compared to the non-DCI patients. The most enriched biological process was the positive regulation of autophagy, followed by the response to mitochondrial depolarization. The molecular functions ubiquitin-like protein ligase binding and ubiquitin-protein ligase binding were enriched. In the cluster of cellular components, Lewy bodies and the phagophore assembly site were enriched. BECN1 was the most connected gene among the differentially expressed markers related to autophagy and mitophagy in the development of DCI. Conclusion : Our study may provide novel insight into mitochondrial dysfunction in DCI pathogenesis.

• Journal of Applied Biological Chemistry
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• v.50 no.3
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• pp.109-114
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• 2007

Sar1p is a ras-related GTP-binding protein that functions in intracellular protein transport between the endoplasmic reticulum (ER) and the Golgi complex. The effector domain of Ras family proteins is highly conserved and this domain is functionally interchangeable in plant, yeast and mammalian Sar1. Using a recombinant Brassica sar1 protein (Bsar1p) harboring point mutations in its effector domain, we here investigated the ability of Sar1p to bind and hydrolyze GTP and to interact with the two sar1-specific regulators, GTPase activating protein (GAP) and guanine exchange factor (GEF). The T51A and T55A mutations impaired Bsar1p intrinsic GTP-binding and GDP-dissociation activity. In contrast, mutations in the switch domain of Bsar1 did not affect its intrinsic GTPase activity. Moreover, the P50A, P54A, and S56A mutations affected the interaction between Bsar1p and GAP. P54A mutant protein did not interact with two regulating proteins, GEF and GAP, even though the mutation didn't affect the intrinsic GTP-binding, nucleotide exchange or GTPase activity of Bsar1p.