Publications by authors named "Heyjin Lee"

The anticancer effects of Shinan (Shinan-South Korea) sea salts on azoxymethane (AOM)/dextran sodium sulfate (DSS) with high fat diet (HFD)-induced colon cancer and obesity in C57BL/6N mice were studied. We prepared three types of sea salt: generally manufactured sea salt (GS), generally manufactured after filtering seawater (FS), and manufactured with only new seawater (NS). Sea salt intake increased colon length and reduced colon length/weight ratio, tumor number, and progression of colon cancer in colon tissue.

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Cachexia and sarcopenia are the main causes of muscle atrophy. These result in a reduction in the muscle fiber area, myo-protein content, and muscle strength, with various molecular modulators being involved. Although several reports have proposed potential therapeutic agents, no effective treatments have been found for muscle atrophy.

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To overcome the muscle atrophy, such as cachexia and sarcopenia, we tried to find myogenic agents from medicinal plants. From myogenic extract of Coptis japonica, we purified six isoquinoline alkaloids and evaluated their effects on transactivation of myoD and MHC expression in C2C12 cells during differentiation process. Among obtained compounds, magnoflorine most efficiently enhanced the myoblast differentiation by activating the p38 MAP kinase and Akt pathway, and also increased the number of multinucleated and cylinder-shaped myotubes.

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14-3-3 is a family of highly conserved protein that is involved in a number of cellular processes. In this study, we identified that the high expression of 14-3-3γ in various cancer cell lines correlates with the invasiveness of the cancer cells. Overexpression of 14-3-3γ causes changes to the morphologic characteristics of cell transformation, and promotes cell migration and invasion.

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Background: A plethora of biological metabolisms are regulated by the mechanisms of ubiquitination, wherein this process is balanced with the action of deubiquitination system. Dub-2 is an IL-2-inducible, immediate-early gene that encodes a deubiquitinating enzyme with growth regulatory activity. DUB-2 presumably removes ubiquitin from ubiquitin-conjugated target proteins regulating ubiquitin-mediated proteolysis, but its specific target proteins are unknown yet.

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SDS3 is a key component of the histone deacetylase (HDAC)-dependent Sin3A co-repressor complex, serving to maintain its HDAC activity. Here, we report both exogenous and endogenous functional interaction between deubiquitinating enzyme USP17 and human SDS3 by MALDI-TOF-MS, co-immunoprecipitation assay, and GST pull-down assay. In this study, we demonstrated that SDS3 readily undergoes endogenous polyubiquitination, which is associated specifically with Lys-63-branched polyubiquitin chains and not with Lys-48-branched polyubiquitin chains.

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Translational studies have explored the therapeutic effects of stem cells, raising hopes for the treatment of numerous diseases. Here, we evaluated the therapeutic effect of chorionic plate-derived mesenchymal stem cells (CP-MSCs) isolated from human placenta and transplanted into rats with carbon tetrachloride (CCl(4))-injured livers. CP-MSCs were analyzed for hepatocyte-specific gene expression, indocyanine green (ICG) uptake, glycogen storage, and urea production following hepatogenic differentiation.

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Cell-cell interactions between muscle precursors are required for myogenic differentiation; however, underlying mechanisms are largely unknown. Promyogenic cell surface protein Cdo functions as a component of multiprotein complexes containing other cell adhesion molecules, Boc, Neogenin and N-cadherin, and mediates some of signals triggered by cell-cell interactions between muscle precursors. Cdo activates p38MAPK via interaction with two scaffold proteins JLP and Bnip-2 to promote myogenesis.

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In regulation of the developmental process, the balance between cellular proliferation and cell death is critical. Placental development tightly controls this mechanism, and increased apoptosis of placental trophoblasts can cause a variety of gynecological diseases. Members of the immortalization-upregulated protein (IMUP) family are nuclear proteins implicated in SV40-mediated immortalization and cellular proliferation; however, the mechanisms by which their expression is regulated in placental development are still unknown.

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Ubiquitination and deubiquitination have a critical role in protein homoeostasis in the cell. Here, we have characterized a novel USP44 (ubiquitin-specific protease 44), which has a ZnF-UBP (zinc-finger ubiquitin-specific protease) domain and conserved cysteine, histidine and asparagine/aspartic acid residues characteristic of deubiquitinating enzymes. The biochemical assay revealed that USP44 can cleave ubiquitin from ubiquitinated substrates both in vitro and in vivo.

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Mouse Usp42, a novel ubiquitin specific protease gene, was isolated from mouse embryonic stem cells. It consists of 1,324 amino acids with a predicted molecular weight of 146kDa and contains the conserved Cys, Asp (I), His and Asn/Asp (II) domains defined as one of characteristics for deubiquitinating enzymes. RT-PCR analysis showed that the Usp42 transcript is expressed in NIH3T3 cells, B- and T-lymphocytes, and L1210 cells.

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Deubiquitinating enzymes regulate a number of cellular mechanisms including pre-implantation, growth and differentiation, oncogenesis, cell cycle progression, transcriptional activation, and signal transduction. In this study, we have identified a novel human deubiquitinating enzyme gene, USP22, and its mouse homologue, Usp22. They encode 525 amino acids (approximate MW: 60kDa) and contains Cys, Asp (I), His and Asp/Asn (II), the highly conserved domains of the UBP family of deubiquitinating enzymes.

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p53 tumor suppressor protein is stabilized by the herpes-virus-associated ubiquitin-specific protease (HAUSP), a deubiquitinating enzyme. We previously isolated a mouse orthologue of HAUSP, mHAUSP, encoding 1103 amino acids with a molecular weight of approximately 135 kDa containing highly conserved Cys, Asp (I), His, and Asn/Asp (II) domains. In this study, we investigated the temporal and spatial expression of mHAUSP during the early mouse embryonic development.

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