• Biomedical Science Letters
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• v.12 no.2
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• pp.73-79
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• 2006

Nebulin is a giant ($600{\sim}900$ kDa), modular sarcomeric protein proposed to regulate the assembly, and to specify the precise lengths of actin filamints in vertebrate skeletal muscles. Recently, There is an evidence that the nebulin also expressed in non muscle tissue, brain and liver. We identified a new isoform of nebulin from adult brain library by PCR screening. It contains two simple-repeats exon 165, 166 and linker-repeats exon $154{\sim}161$ except exon 159. The nebulin modules M160 to M170 (exon 150 to exon 161) has been shown to bind desmin. In mature striated muscle, desmin intermediate filaments surround Z-discs and link individual myofibrils laterally at their Z-discs and to other intracellular structures, including the costameres and the intercalated discs of the sarcolemma, sarcoplasmic reticulum, mitochondria, T-tubules, and nuclei. Therefore, it is an interesting possibility that the differential splice pathways within the linker region of nebulin modify the affinity of nebulin's interaction with desmin. The specific interactions of nebulin and desmin were confirmed in vivo by yeast two hybrid experiments. To verify in the cellular level the interaction between nebulin isoform and desmin, we transfected COS-7 cell with EGFP-tagged nebulin and DsRed-tagged desmin. Based on evidence showing that despite exon 159 was deleted, the new isoform of nebulin was interact with desmin. This suggest that nebulin in brain may interact with another intermediate filament. The conservation of these ligand-binding capacity in brain and skeletal nebulins suggest that nebulins may have conserved roles in brain and skeletal muscle.

• BMB Reports
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• v.38 no.2
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• pp.218-224
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• 2005

Antioxidant enzymes are related to the resistance to various abiotic stresses including salinity. Barley is relatively tolerant to saline stress among crop plants, but little information is available on barley antioxidant enzymes under salinity stress. We investigated temporal and spatial responses of activities and isoform profiles of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), non-specific peroxidase (POX), and glutathione reductase (GR) to saline stress in barley seedlings treated with 200 mM NaCl for 0, 1, 2, 5 days, respectively. In the control plant, hydrogen peroxide content was about 2-fold higher in the root than in the shoot. Under saline stress, hydrogen peroxide content was decreased drastically by 70% at 2 d after NaCl treatment (DAT) in the root. In the leaf, however, the content was remained unchanged by 2 DAT and increased about 14 % at 5 DAT. In general, the activities of antioxidant enzymes were increased in the root and shoot under saline stress. But the increase was more significant and consistent in the root. The activities of SOD, CAT, APX, POX, and GR were increased significantly in the root within 1 DAT, and various elevated levels were maintained by 5 DAT. Among the antioxidant enzymes, CAT activity was increased the most drastically. The significant increase in the activities of SOD, CAT, APX, POX, and GR in the NaCl-stressed barley root was highly correlated with the increased expression of the constitutive isoforms as well as the induced ones. The hydrogen peroxide content in the root was most highly correlated with the CAT activity, indicating an increased role of CAT in hydrogen peroxide detoxification under salinity stress. In addition, the results suggest the significance of temporal and spatial regulation of each antioxidant isoform in determining the competence of the antioxidant capacity under saline stress.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.247-255
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• 2003

A bacterium, KJA-118 showing a strong chitinase activity, was isolated and identified as Bacillus cereus. The strain produced maximum level of chitinase, when grown aerobically at $30^{\circ}C$ for 4 days in basal broth containing 1% colloidal chitin in the initial pH adjusted to 6.0. Among various carbon sources such as crab shell powder, chitin powder, colloidal chitin, and R. solani mycelium, maximum chitinase activity was found in culture broth supplemented with R. solani mycelium. When KJA-118 was incubated with R. solani, the cell wall of the fungus was found to be completely destroyed. SDS-PAGE and active staining results revealed that KJA-118 produced three isoforms of chitinase with molecular weights of 68 kDa, 47 kDa, and 37 kDa. When the suspension of KJA-118 was treated to cucumber seedlings, reducing rate of damping-off caused by R. solani was about 28.1%.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.449-454
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• 2009

5'-AMP-activated protein kinase (AMPK) is a heterotrimeric complex consisting of a catalytic ($\alpha$) and two regulatory ($\beta$ and $\gamma$) subunits. Two isoforms are known for catalytic subunit (${\alpha}1$, ${\alpha}2$) and are encoded by different genes. To assess the metabolic effects of $AMPK{\alpha}1$, we examined the effects of overexpression of adenoviral-mediated $AMPK{\alpha}1$ in hyperlipidemic type 2 diabetic rats. The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an established animal model of type 2 diabetes that exhibits chronic and slowly progressive hyperglycemia and hyperlipidemia. Thirty five-week-old overt type 2 diabetic rats (n=10) were administered intravenously with Ad.$AMPK{\alpha}1$. AMPK activity was measured by phosphorylation of acetyl CoA carboxlyase (ACC). To investigate the changes of gene expression related glucose and lipid metabolism, quantitative real-time PCR was performed with liver tissues. Overexpression of $AMPK{\alpha}1$ showed that blood glucose concentration was decreased but that glucose tolerance was not completely recovered on 7th day after treatment. Plasma triglyceride concentration was decreased slightly, and hepatic triglyceride content was markedly reduced by decreasing expression of hepatic lipogenic genes. Overexpression of $AMPK{\alpha}1$ markedly improved hepatic steatosis and it may have effective role for improving hepatic lipid metabolism in hyperlipidemic state.

• International Journal of Oral Biology
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• v.45 no.3
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• pp.107-114
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• 2020

Acacetin, which is present in damiana (Turnera diffusa) and black locust (Robinia pseudoacacia), has several pharmacologic activities such as antioxidant, anti-inflammatory, and anti-proliferative effects on cancer cells. However, the effect of acacetin on head and neck cancers has not been clearly established. This study aimed to examine the effects of acacetin on cell growth and apoptosis induction in FaDu human pharyngeal carcinoma cells. These were investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, Live/Dead cell assay, 4',6-diamidino-2-phenylindole dihydrochloride staining, caspase-3 and caspase-7 activation assay, and immunoblotting in FaDu cells. Acacetin induced FaDu cell death in a dose-dependent manner, with an estimated IC₅₀ value of 41.9 µM, without affecting the viability of L-929 mouse fibroblasts as normal cells. Acacetin treatment resulted in nuclear condensation in the FaDu cells. It promoted the proteolytic cleavage of procaspase-3, -7, -8, and -9 with increasing amounts of the cleaved caspase isoforms in FaDu cells. Acacetin-induced apoptosis in FaDu cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting showed downregulation of the anti-apoptotic mitochondrial proteins Bcl-2 and Bcl-xL, but upregulation of the mitochondria-dependent pro-apoptotic proteins Bax and Badin FaDu cells after acacetin treatment. These findings indicate that acacetin inhibits cell proliferation and induces apoptotic cell death in FaDu human pharyngeal carcinoma cells via both the death receptor-mediated extrinsic apoptotic pathway and the mitochondria-mediated intrinsic apoptotic pathway.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.294-298
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• 2009

Purpose: The development of a microvascularization is important for the homeostasis of normal bone. Vascular endothelial growth factor (VEGF) is one of the most important factors in vessel formation. The purpose of this study was to examine VEGF-related autocrine growth in periosteal-derived cells. Materials and methods: Periosteal-derived cells were obtained from mandibular periosteums and introduced into the cell culture. After passage 3, the periosteal-derived cells were further cultured for 21 days in an osteogenic inductive culture medium containing dexamethasone, ascorbic acid, and $\beta$-glycerophosphate. Results: The expression of four VEGF isoforms and VEGFRs was observed in periosteal-derived cells. Treatment with cultures with VEGFR-1 and VEGFR-2 Kinase Inhibitor inhibited osteoblastic differentiation and alkaline phosphatase (ALP) activity of periosteal-derived cells. In addition, exogenous VEGF treatment increased calcium content in the periosteal-derived cells. Conclusion: These results suggest that VEGF might act as an autocrine growth molecule during osteoblastic differentiation of cultured human periosteal-derived cells.

• Interdisciplinary Bio Central
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• v.1 no.1
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• pp.1.1-1.5
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• 2009

Many organisms control their physiology and behavior in response to the local light environment, which is first perceived by photoreceptors that undergo light-dependent conformational changes. Phytochromes are one of the major photoreceptors in plants, controlling wide aspects of plant physiology by recognizing the light in red (R) and far-red (FR) spectra. Higher plants have two types of phytochromes; the photo-labile type I (phyA in Arabidopsis) and photo-stable type II (phyB-E in Arabidopsis). Phytochrome B (phyB), a member of the type II phytochromes in Arabidopsis, shows classical R and FR reversibility between the inter-convertible photoisomers, Pr and Pfr. Interestingly, the Pr and Pfr isomers show partitioning in the cytosol and nucleus, respectively. In the over 50 years since its discovery, it has been thought that the type II phytochromes only function to mediate R light. As described in the text, we have now discovered phyB has an active function in FR light. Even striking is that the R and FR light exert an opposite effect. Thus, FR light is not simply nullifying the R effect but has an opposing effect to R light. What is more interesting is that the phyB-mediated actions of FR and R light occur at different cellular compartment of the plant cell, cytosol and nucleus, respectively, which was proven through utilization of the cytosolic and nuclear-localized mutant versions of phyB. Our observations thus shoot down a major dogma in plant physiology and will be considered highly provocative in phytochrome function. We argue that it would make much more sense that plants utilize the two isoforms rather than only one form, to effectively monitor the changing environmental light information and to incorporate the information into their developmental programs.

• Biomedical Science Letters
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• v.2 no.2
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• pp.175-185
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• 1996

The mitogen-activated protein(MAP) kinase signal transduction pathway represents an important mechanism by which mitogen, such as serum and PMA, regulate cell proliferation and differentiation. Target substrates of the MAP kinase are located within several compartments containing plasma membranes and nucleus. We now report that serum addition induces proliferation of the P388 murine leukemia cell, but PMA does not, while both serum and PMA treatment cause translocation of the MAP kinase, mainly p42$^{mapk}$ isoform, from cytosol into the nucleus, which was monitored by immunoblot analysis using polyclonal anti-ERK1 antibodies. We investigated whether the MAP kinase was capable of phosphorylating c-Jun protein and GST-fusion proteins, the P562$^{kk}$N-terminal peptides (1-77 or 1-123 domain) of the T cell tyrosine kinase, using the partially purified MAP kinase by SP-sephadex C-50, phenyl superose and Mono Q column chromatography. We found that the partially purified MAP kinase was able to phosphorylate c-Jun protein and the GST-fusion protein expressed using E.coli DH5$\alpha$ which is transformed with pGEX-3Xb plasmid vector carrying of p562$^{kk}$N-terminal peptide-encoding DNA. These results imply that tyrosine kinase receptor/Ras/Raf/MAP kinase pathway is a major mechanism for mitogen-induced cell proliferation in P388 murine leukemia cell and that the various MAP kinase isoforms may have their own target substrates located in distinct subcellular compartments.

• Journal of Life Science
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• v.20 no.2
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• pp.202-207
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• 2010

Ras genes are responsible for up to 30% of human tumor mutations and are composed of three isoforms: H-Ras, K-Ras and N-Ras. The post-translational modification of the CAAX motif of the Ras protein is essential in Ras actions. In the present study, we studied the effects of novel farnesyl transferase inhibitors (FTIs), YH3938 and YH3945, on the actions of oncogenic mutants of H-Ras, K-Ras and N-Ras. YH3938 and YH3945 completely reverted the proliferation and morphology of oncogenic H-Ras-transformed Rat2 cells, but not of oncogenic K-Ras-transformed Rat2 cells. Oncogenic N-Ras-transformed Rat2 cells were slightly affected. Activation of SRE promoters by oncogenic H-Ras and N-Ras, but not by K-Ras, were inhibited by treatment with YH3938 and YH3945. Using bandshift analysis, YH3938 suppressed the processing of oncogenic H-Ras and N-Ras, but not that of oncogenic K-Ras protein. YH3945 only inhibited the processing of H-Ras. From these results, we conclude that YH3938 and YH3945 specifically inhibit actions of oncogenic H-Ras through inhibition of its farnesylation, that YH3938 also inhibits N-Ras activity in a dose-dependent manner, and that these drugs have no effect on oncogenic K-Ras activity.

• Journal of Ginseng Research
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• v.42 no.1
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• pp.50-56
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• 2018

Background: Saponins from Panax japonicus (SPJ) are the most abundant and main active components of P. japonicus, which replaces ginseng roots in treatment for many kinds of diseases in the minority ethnic group in China. Our previous studies have demonstrated that SPJ has the effects of anti-inflammation through the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-${\kappa}B$) signaling pathways. The present study was designed to investigate whether SPJ can modulate intestinal tight junction barrier in aging rats and further to explore the potential mechanism. Methods: Aging rats had been treated with different doses (10 mg/kg, 30 mg/kg, and 60 mg/kg) of SPJ for 6 mo since they were 18 mo old. After the rats were euthanized, the colonic samples were harvested. Levels of tight junctions (claudin-1 and occludin) were determined by immunohistochemical staining. Levels of proinflammatory cytokines (interleukin-$1{\beta}$ and tumor necrosis factor-${\alpha}$) were examined by Western blot. NF-${\kappa}B$ and phosphorylation of MAPK signaling pathways were also determined by Western blot. Results: We found that SPJ increased the expression of the tight junction proteins claudin-1 and occludin in the colon of aging rats. Treatment with SPJ decreased the levels of interleukin-$1{\beta}$ and tumor necrosis factor-${\alpha}$, reduced the phosphorylation of three MAPK isoforms, and inhibited the expression of NF-${\kappa}B$ in the colon of aging rats. Conclusion: The studies demonstrated that SPJ modulates the damage of intestinal epithelial tight junction in aging rats, inhibits inflammation, and downregulates the phosphorylation of the MAPK and $NF-{\kappa}B$ signaling pathways.