• The Korean Journal of Physiology and Pharmacology
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• 제4권5호
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• pp.347-353
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• 2000

It has been well documented that a massive release of not only glutamate but also other neurotransmitters may modulate the final responses of nerve cells to the ischemic neuronal injury. But there is no information regarding whether the release of monoamines is directly associated with synaptic vesicular proteins under ischemia. In the present study, it was investigated whether synapsin 1, syntaxin and SNAP-25 are involved in the release of 5-hydroxytryptamine $([^3H]5-HT)$ in glucose/oxygen deprived (GOD) rat hippocampal slices. And, the effect of NMDA receptor using DL-2-amino-5-phosphonovaleric acid (APV) on ischemia- induced release of 5-HT and the changes of the above proteins were also investigated. GOD for 20 minutes enhanced release of $[^3H]5-HT,$ which was in part blocked by the NMDA receptor antagonist, APV. The augmented expression of synapsin 1 during GOD for 20 minutes, which was also in part prevented by APV. In contrast, the expression of syntaxin and SNAP-25 were not altered during GOD. These results suggest that ischemic insult induces release of $[^3H]5-HT$ associated with synapsin 1, synaptic vesicular protein, via activation of NMDA receptor in part.

• 한국자기공명학회논문지
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• 제14권2호
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• pp.88-104
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• 2010

Human melanocortin-4 receptor (hMC4R) has a critical role in part of energy homeostasis, and their heterozygous mutations related in genetic cause of severe human obesity. In order to study the structure and function of these membrane proteins, it is important to prepare the samples. However, the preparation of transmembrane peptide is seriously difficult and time-consuming. Overexpression and purification of membrane proteins was reported to be difficult due to their innate insoluble and toxic properties. Among the many difficulties, the most important is the difficulty in obtaining sufficient quantities of purified protein. Recently, we succeed to produce large amounts of the second transmembrane domain from the wild-type hMC4R (wt-TM2) and D90N mutant hMC4R (m-TM2) and proposed the structural difference of them in membrane-like environments. In this paper, we demonstrate the optimization procedures to express and purify wt-TM2 or m-TM2 peptides, and solution NMR studies in different detergents to get high-resolution spectra were also described.

• BMB Reports
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• 제46권9호
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• pp.465-470
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• 2013

Bone morphogenetic proteins (BMPs) have diverse and important roles in the proliferation and differentiation of adult stem cells in our tissues. Especially, BMPs are well known to be the main inducers of bone formation, by facilitating both proliferation and differentiation of bone stem cells. Interestingly, in skin stem cells, BMPs repress their proliferation but are indispensable for the proper differentiation into several lineages of skin cells. Here, we tested whether BMP antagonists have an effect on the prevention of wrinkle formation. For this study we used an in vivo wrinkle-induced mouse model. As a positive control, retinoic acid, one of the top anti-wrinkle effectors, showed a 44% improvement compared to the non-treated control. Surprisingly, bone morphogenetic protein receptor 1a extracellular domain (BMPR1a-ECD) exhibited an anti-wrinkle effect which was 6-fold greater than that of retinoic acid. Our results indicate that BMP antagonists will be good targets for skin or hair diseases.

• Fisheries and Aquatic Sciences
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• 제21권2호
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• pp.4.1-4.5
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• 2018

Insulin-like growth factors (IGFs), along with IGF-binding protein and IGF receptor, are well-known regulators in the growth and survival of vertebrates. In this study, we investigated the involvement of IGFs and protein variation during embryonic development of the olive flounder (Paralichthys olivaceus). Morphological stages were divided into six main developments as blastula, gastrula, cephalization, cranial regionalization, tail lift, and hatch. During embryonic development, protein variation was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrospray ionization quadrupole time-of-flight mass spectrometry/mass spectrometry. In addition, the mechanism of signaling of IGF-I receptor was examined using immuno-blot analysis. We found marked changes in protein expression at four stages of embryonic development and identified proteins as belonging to the vitellogenin 2 family. As development progresses, expression of IGF-II, phosphotyrosine, and phospho-Akt increased, while expression of growth factor receptor-bound protein 2 (GRB2) and one of guanine-nucleotide-binding proteins (Ras) decreased. These results provide basic information on the IGF system in the embryonic development of the olive flounder.

• Animal cells and systems
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• 제14권3호
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• pp.155-160
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• 2010

Extracellular signal-regulated kinases 1/2 (ERK1/2) play important roles in a variety of biological processes including cell growth and differentiation. We have previously reported that GAR-3 activates ERK1/2 via phospholipase C and protein kinase C, presumably through pertussis toxin (PTX)-insensitive Gq proteins, in Chinese hamster ovary (CHO) cells. Here we provide evidence that GAR-3 also activates ERK1/2 through PTX-sensitive G proteins, phosphatidylinositol 3-kinase (PI 3-kinase), and Src family kinases in CHO cells. We further show that in human embryonic kidney (HEK293) cells, epidermal growth factor receptor and Ras are required for efficient ERK1/2 activation by GAR-3. Taken together, our data indicate that GAR-3 evokes ERK1/2 activation through multiple signaling pathways in cultured mammalian cells.

• Biomolecules & Therapeutics
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• 제25권1호
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• pp.4-11
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• 2017

Heterotrimeric G proteins are key intracellular coordinators that receive signals from cells through activation of cognate G protein-coupled receptors (GPCRs). The details of their atomic interactions and structural mechanisms have been described by many biochemical and biophysical studies. Specifically, a framework for understanding conformational changes in the receptor upon ligand binding and associated G protein activation was provided by description of the crystal structure of the ${\beta}2$-adrenoceptor-Gs complex in 2011. This review focused on recent findings in the conformational dynamics of G proteins and GPCRs during activation processes.

• 생물정신의학
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• 제20권1호
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• pp.1-5
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• 2013

Glutamate receptors are important components of synaptic transmission in the nervous system. Especially, ${\alpha}$-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors mediate most abundant excitatory synaptic transmission in the brain. There is elaborate mechanism of regulation of AMPA receptors including protein synthesis/degradation, intracellular trafficking, exocytosis/endocytosis and protein modification. In recent studies, it is revealed that functional dysregulation of AMPA receptors are related to major psychiatric disorders. In this review, we describe the structure and function of AMPA receptors in the synapse. We will introduce three steps of mechanism involving trafficking of AMPA receptors to neuronal membrane, lateral diffusion into synapses and synaptic retention by membrane proteins and postsynaptic scaffold proteins. Lastly, we will describe recent studies showing that regulation of AMPA receptors is important pathophysiological mechanism in psychiatric disorders.

• 대한불안의학회지
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• 제2권2호
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• pp.79-85
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• 2006

Anxiety and anxiety disorders are related to many neurotransmitters, such as norepinephrine, serotonine, dopamine, glutamate, and Gamma-aminobutyric acid (GABA). GABA, the main inhibitory neurotransmitter of the CNS, is known to counterbalance the action of the excitatory neurotransmitters and control anxiety. GABA acts on 3 GABA receptor subtypes, $GABA_A$, $GABA_B$, and $GABA_C$. $GABA_A$ and $GABA_c$ receptors are oligomeric transmembrane glycoproteins composed of 5 subunits that are arranged around a central chloride channel. $GABA_B$ receptor comprises two 7-transmembraneis-spanning proteins that are coupled to either calcium or potassium channel via G proteins. This article highlights neurobiological interactions between anxiety and GABA system.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.483-489
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• 2002

The role of $G{\alpha}12\;and\;G{\alpha}13$ in modulating the IgE receptor-mediated histamine secretion in the streptolysin-o-permeabilized human cultured mast cell was investigated. The expression of $G{\alpha}12\;and\;G{\alpha}13$ proteins were regulated during human cultured mast cell differentiation, and a significant correlation was observed between the levels of expression of $G{\alpha}12\;and\;G{\alpha}13$ proteins and IgE receptor-mediated histamine secretion capability in human cultured mast cells. Antibodies against $G{\alpha}12\;and\;G{\alpha}13$ effectively inhibited the IgE receptor-induced histamine release, and the concentration of anti-$G{\alpha}12$ antibody used to inhibit histamine secretion was shown to also inhibit the IgE receptor-mediated elevation of intracellular $Ca^2+$. Therefore, the results suggest that $G{\alpha}12\;and\;G{\alpha}13$ play roles in modulating IgE receptor-activated $Ca^2+$ influx, thereby regulating histamine release in cultured human mast cells. This is the first report to show that $G{\alpha}12\;and\;G{\alpha}13$ are involved in the regulation of $Ca^2+$ mediated exocytosis in human cultured mast cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.287-293
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• 2009

Cell survival is the result of a balance between programmed cell death and cellular proliferation. Cell membrane receptors and their associated signal transducing proteins control these processes. Of the numerous receptors and signaling proteins, epidermal growth factor receptor (EGFR) is one of the most important receptors involved in signaling pathways implicated in the proliferation and survival of cancer cells. EGFR is often highly expressed in human tumors including oral squamous cell carcinomas, and there is increasing evidence that high expression of EGFR is correlated with poor clinical outcome of common human cancers. Therefore, we examined the antiproliferative activity of gefitinib, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), in head and neck cancer cell lines. SCC-9, KB cells were cultured and growth inhibition activity of gefitinib was measured with MTT assay. To study influence of gefitinib in cell cycle, we performed cell cycle analysis with flow cytometry. Western blot was done to elucidate the expression of EGFR in cell lines and phosphorylation of EGFR and downstream kinase protein, Erk and Akt. Significant growth inhibition was observed in SCC-9 cells in contrast with KB cells. Also, flow cytometric analysis showed G1 phase arrest only in SCC-9 cells. In Western blot analysis for investigation of EGFR expression and downstream molecule phosphorylation, gefitinib suppressed phosphorylation of EGFR and downstream protein kinase Erk, Akt in SCC-9. However, in EGFR positive KB cells, weak expression of active form of Erk and Akt and no inhibitory activity of phosphorylation in Erk and Akt was observed. The antiproliferative activity of gefitinib was not correlated with EGFR expression and some possibility of phosphorylation of Erk and Akt as a predictive factor of gefitinib response was emerged. Further investigations on more reliable predictive factor indicating gefitinib response are awaited to be useful gefitinib treatment in head and neck cancer patients.