• YAKHAK HOEJI
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• v.47 no.1
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• pp.31-36
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• 2003

To investigate the effect of protein kinase on melanin production via cAMP-dependent pathway, we measured the melanin amount and tyrosinase activity in B16 melanoma cells stimulated by alpha-melanocyte stimulating hormone (MSH), forskolin and 8-Br-cAMP. MSH, forskolin and 8-Br-cAMP significantly increased both melanin production and tyrosinase activity in B16 cells. Melanin production and tyrosinase activity by MSH are significantly inhibited by cyclic AMP-dependent protein kinase inhibitor (KT5720) and protein kinase C down-regulation treated with PMA. Bisindolmaleimide (1$\mu$M), protein kinase C inhibitor, significantly inhibited melanin production and tyrosinase activity stimulated by MSH, forskolin and 8-Br-cAMP with the following order of potency: MSH＞forskolin＞8-Br-cAMP. Tyrosine kinase inhibitor, genistein and DHC, significantly inhibited both, but the inhibitory effect was more potent in 8-Br-cAMP-stimulated B16 cells than MSH-stimulated cells. NFkB inhibitor (parthenolide) significantly inhibited melanin production and tyrosinase activity. Neither melanin production nor tyrosinase activity induced by MSH, forskolin and 8-Br-cAMP were affected by KN-62 (calmodulin-dependent protein kinase II inhibitor), PD098059 (mitogen-activated protein kinase inhibitor, MAPKK) and worthmannin (phosphatidylinositol 3-kinase inhibitor). These results suggest that both protein kinase C and tyrosine kinase are involved in melanin production by cyclic AMP-dependent pathway and NFkB pathway may play an important role in cyclic AMP-dependent melanin production in B16 melanoma cells.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.447-451
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• 2021

In this study, we discovered for the first time that linarin, a flavonoid compound, enhances melanin biosynthesis in B16F10 cells, and subsequently elucidated the underlying mechanism of linarin-induced melanogenesis. Linarin showed no cytotoxicity at a concentration of 42 μM and significantly increased intracellular tyrosinase activity and melanin content in B16F10 cells. Mechanistic analysis showed that linarin increased the expression of tyrosinase, tyrosinase-related protein 1 (TRP-1), and microphthalmia-associated transcription factor (MITF) that are related to melanogenesis. Moreover, linarin decreased the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (AKT). Finally, we evaluated the effect of the structure-activity relationship of linarin and its aglycone on melanogenesis. The results indicated that linarin enhances the expression of melanogenic proteins by activating MITF expression via the modulation of mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K), and protein kinase B signaling pathways in B16F10 cells, thereby enhancing melanogenesis.

• Environmental Analysis Health and Toxicology
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• v.20 no.3 s.50
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• pp.229-235
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• 2005

태양광선,특히 자외선 B에 대한 환경적 노출은 편평세포암과 기저세포암을 포함하는 흑색선종 이외의 피부암과 크게 관련된다고 알려져 있다. 염기 류신 지퍼계 전사조절인자인 CChAT/enhancer binding protein-alpha는 표피 각질형성세포에서 다량으로 발현되었고, 각질형성세포의 증식을 억제하며 피부암 발생을 억제하는 유전자로서의 역할이 암시된 바 있다. 최근 자외선 B가 각질형성세포에서 p53에 의한 CCAAT/enhanrer binding protein-alpha의 발현을 강력하게 유도한다는 것이 보고되었다. 이러한 CCAAT/enhancer binding protein-alpha 단백질 발현의 유도는 세포 성장 억제 세포고사와 함께 일어났다. 이 연구는 glycogen synthase kinase-3 길항제가 자외선 B에 의한 CCAAT/enhancer binding protein-alpha 유도를 억제하며 변이 kinase-불활성 GSK의 강제 발현은 자외선 B가 CCAAT/enhancer binding protein-alpha전사조절부위 활성의 증가를 억제한다는 것을 보여주었다. 즉 자외선 B에 의한 CCAAT/enhancer binding protein-alpha의 유도가 p53과 활성 glycogen synthase kinase-3에 의한 것이라는 것을 증명하였다.

• Tuberculosis and Respiratory Diseases
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• v.53 no.6
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• pp.595-611
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• 2002

Akt/PKB protein kinase B, ALI acute lung injury, ARDS acute respiratory distress syndrome, CREB C-AMP response element binding protein, ERK extracelluar signal-related kinase, fMLP fMet-Leu-Phe, G-CSF granulocyte colony-stimulating factor, IL interleukin, ILK integrin-linked kinase, JNK Jun N-terminal kinase, LPS lipopolysaccharide, MAP mitogen-activated protein, MEK MAP/ERK kinase, MIP-2 macrophage inflammatory protein-2, MMP matrix metalloproteinase, MPO myeloperoxidase, NADPH nicotinamide adenine dinucleotide phosphate, NE neutrophil elastase, NF-kB nuclear factor-kappa B, NOS nitric oxide synthase, p38 MAPK p38 mitogen activated protein kinase, PAF platelet activating factor, PAKs P21-activated kinases, PMN polymorphonuclear leukocytes, PI3-K phosphatidylinositol 3-kinase, PyK proline-rich tyrosine kinase, ROS reactive oxygen species, TNF-${\alpha}$ tumor necrosis factor-a.

• Journal of Microbiology
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• v.39 no.4
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• pp.314-320
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• 2001

Macrophages stimulated by lipopolysaccharide(LPS) from gram negative bacteria undergo activation of a group of immediate early genes including Rantes. The mouse Rantes gene promoter region contains an LPS rsponsive element(LPE) We detected 3 specific bands termed B1, B2 and 3 formed by the interaction of the LPE and proteins found in LPS-stimulated RAW 367.7 cells. An additional band B4 was determined to be an Ap-1 binding protein. The B1 band appears within 1 hour of LPS nuclear extracts from LPS-stimulation, and this protein kinase enhances B1 and formation. The B1 band can be converted to band B2/B3 by adding specific heparin column fraction purified Ser/Thr specific protein phosphatases PP-1 and PP-2A can stimulate the same conversion to about the same extent. Thus, the formation of the LRE sequence binding complex appears to be regulated by Ser/Thr protein kinase and one or more Ser/Thr specific phosphatases. At least four proteins are involved in the trgulation of the LRE-dependent Rants experssion: two binding factors that bind directly to the target sequences. and two factors that control their binding. The future purification and characterization of these binding pro-teins will reveal in detail the mechanism of Rantes gene activation after LPS stimulation.

• Journal of Integrative Natural Science
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• v.6 no.4
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• pp.234-243
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• 2013

N-terminal kinase-like (NTKL) protein was initially identified as a protein binding to protein kinase B (PKB, also known as Akt). Though NTKL-BP1 (NTKL-binding protein 1) has been identified as an NTKL binding protein, its functions related to binding have not yet been elucidated. Here, a new alternative spliced variant of NTKL and its association with integrin ${\beta}1$ is described, in addition to the kinase activity of NTKL and its substrate candidates. Although the phosphorylation of the candidates must be further confirmed using other experimental methods, the observation that NTKL can phosphorylate ROCK1, DYRK3, and MST1 indicates that NTKL may act as a signaling protein to regulate actin assembly, cell migration, cell growth, and to facilitate differentiation and development in an integrin-associated manner.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.11-18
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• 1999

Nuclear factor $_{\kappa}B\;(NF-_{\kappa}B)$ activation is modulated by various protein kinases. Activation of $NF-_{\kappa}B$ is known to be important in the regulation of cell viability. The present study investigated the effect of inhibitors of protein tyrosine kinase (PTK), protein kinase C (PKC) and protein kinase A (PKA) on $NF-_{\kappa}B$ activity and the viability of bovine cerebral endothelial cells (BCECs). In serum-deprivation-induced BCEC death, low doses of $TNF{\alpha}$ showed a protective effect. $TNF{\alpha}$ induced $NF-_{\kappa}B$ activation within 4 h in serum-deprivation. PTK inhibitors (herbimycin A and genistein) and PKC inhibitor (calphostin C) prevented $NF-_{\kappa}B$ activation stimulated by $TNF{\alpha}.$ Likewise, these inhibitors prevented the protective effect of $TNF{\alpha}.$ In contrast to $TNF{\alpha}-stimulated\;NF-_{\kappa}B$ activity, basal $NF-_{\kappa}B$ activity of BCECs in media containing serum was suppressed only by calphostin C, but not by herbimycin A. As well BCEC death was also induced only by calphostin C in serum-condition. H 89, a PKA inhibitor, did not affect the basal and $TNF{\alpha}-stimulated\;NF-_{\kappa}B$ activities and the protective effect of $TNF{\alpha}$ on cell death. These data suggest that modulation of $NF-_{\kappa}B$ activation could be a possible mechanism for regulating cell viability by protein kinases in BCECs.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.224-229
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• 2008

Eucommia ulmoides (Duchung) is commonly used for treatment of diabetes in Korean traditional medicine. However, the exact mechanism of its anti-diabetic effect has not yet been fully elucidated. In this study, the effect of E. ulmoides extract on glucose uptake was investigated in L6 rat skeletal muscle cells. E. ulmoides extract stimulated the activity of phosphatidylinositol (PI) 3-kinase that is a major regulatory molecule in glucose uptake pathway. Protein kinase B (PKB) and protein kinase C-${\xi}$ (PKC-${\xi}$), downstream mediators of PI 3-kinase, were also activated by E. ulmoides extract. We assessed the activity of AMP-activated protein kinase (AMPK), another regulatory molecule in glucose uptake pathway. Phosphorylation level of AMPK did not change with treatment of E. ulmoides extract. Phosphorylations of p38 mitogen activated protein kinase (p38 MAPK) and acetyl-CoA carboxylase (ACC), downstream mediators of AMPK, were not significantly different. Taken together, our results suggest that E. ulmoides may stimulate glucose uptake through PI 3-kinase but not AMPK in L6 skeletal muscle cells.

• BMB Reports
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• v.28 no.4
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• pp.281-289
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• 1995

Homogeneous human deoxycytidine kinase was purified in one step from a variety of spontaneous human leukemic cells (T-ALL, B-ALL, B-CLL, AML, CML), and from cultured T-lymphoblast cells (MOLT-4) using the newly developed affinity medium, $dCp_4$-Sepharose. Starting with an ammonium sulfate fraction, purification was achieved in one step with the kinase being eluted from a column by the end product inhibitor, dCTP. The purified deoxycytidine kinase from T-ALL cells phosphorylated deoxyadenosine and deoxyguanosine, as well as deoxycytidine. The enzyme purified from T-ALL and B-CLL cells yielded one major band with a molecular weight of 52 kDa determined by SDS-polyacrylamide gel electrophoresis. AML and CML cells yielded one 52 kDa band and an extra band of 30 kDa molecular weight. On the other hand, B-ALL and MOLT-4 cells showed a low molecular weight band of 30 kDa only. However, the electrophoretic mobilities of enzymatic activity in 12% non-denaturing gels were identical for the dCyd kinase from all different kinds of leukemic cell lines, except that the B-ALL, B-CLL, and MOLT-4 cell preparations had an extra minor peak, all at the same position. dAdo and dCyd phosphorylating activities comigrated indicating that these activities are all associated with the same protein. Two new methods, a disk implantation method and a nitrocellulose powder method were used with a small amount of enzyme protein to raise polyclonal antibodies against dCyd kinase purified from T-ALL cells.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.507-513
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• 2000

ErbB3/HER3 is a cell surface receptor which belongs to the ErbB/HER subfamily of receptor protein tyrosine kinases. When expressed in NIH/3T3 cells, ErbB3 can form heterodimeric coreceptor with endogenous ErbB2. Among known intracellular effectors of the ErbB2/ErbB3 are mitogen-activated protein kinase (MAPK) and phosphoinositide (PI) 3-kinase. In the present study, we studied relative contributions of above two distinct signaling pathways to the heregulin-induced mitogenic response via activated ErbB3. For this, clonal NIH-3T3 cell lines expressing wild-type ErbB3 and ErbB3 mutants were stimulated with $heregulin{\beta}_1$. While cyclin D1 level was markedly high and further increased by treatment of heregulin in cells expressing wild-type ErbB3, the elimination of either Shc binding or PI 3-kinase binding lowered both levels. This result was supported by the reduction of cyclin $D_1$ expression by preteatment with MAPK kinase inhibitor or PI 3-kinase inhibitor before stimulation with heregulin. In accordance with the cyclin $D_1$ expression, elimination of either Shc binding or PI 3-kinase binding reduced the heregulin-induced DNA synthesis and cell growth rate. Our results obtained by the comparison of wild-type and ErbB3 mutants indicate that the full induction of the cell cycle progression through $G_1/S$ phase by ErbB3 activation is dependent on both Shc/MAPK and PI 3-kinase signal transduction pathways.