http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
HSP25 inhibits radiation-induced apoptosis through reduction of PKCδ-mediated ROS production
Lee, Yoon-Jin,Lee, Dae-Hoon,Cho, Chul-Koo,Chung, Hee-Yong,Bae, Sangwoo,Jhon, Gil-Ja,Soh, Jae-Won,Jeoung, Doo-Il,Lee, Su-Jae,Lee, Yun-Sil Nature Publishing Group 2005 Oncogene Vol.24 No.23
Since radiation-induced caspase-dependent apoptosis and ROS generation were partially prevented by HSP25 overexpression, similar to the treatment of control cells with antioxidant agents such as DPI and tiron, questions arise whether radiation-mediated ROS generation contributes to the apoptotic cell death, and also whether HSP25 overexpression can reduce ROS mediated apoptotic cell death. In the present study, radiation-induced cytochrome c release from mitochondria and activation of caspases accompanied by a decrease of mitochondrial membrane potential in Jurkat T cells were shown to be inhibited by mitochondrial complex I inhibitor rotenone, suggesting that mitochondrial ROS might be important in radiation-induced caspase-dependent apoptosis. When HSP25 was overexpressed, effects similar to the treatment of cells with the antioxidants were obtained, indicating that HSP25 suppressed radiation-induced mitochondrial alteration that resulted in apoptosis. Furthermore, activation of p38 MAP kinase by radiation was associated with radiation-induced cell death and ROS production and PKCδ was an upstream molecule for p38 MAP kinase activation, ROS generation and subsequent caspase-dependent apoptotic events. However, in the HSP25 overexpressed cells, the above-described effects were blocked. In fact, radiation-induced membrane translocation of PKCδ and tyrosine phosphorylation were inhibited by HSP25. Based on the above data, we suggest that HSP25 downregulates PKCδ, which is a key molecule for radiation-induced ROS generation and mitochondrial-mediated caspase-dependent apoptotic events.Oncogene (2005) 24, 3715–3725. doi:10.1038/sj.onc.1208440 Published online 4 April 2005
Lee, Young-Sun,Kim, Yeong-Seok,Kim, Dae-Jin,Hur, Dae-Young,Kang, Jae-Seung,Kim, Young-In,Hahm, Eun-Sil,Cho, Dae-Ho,Hwang, Young-Il,Lee, Wang-Jae The Korean Association of Immunobiologists 2006 Immune Network Vol.6 No.2
Background: CM1 (Centrocyte/-blast Marker I) defined by a mAb developed against concanavalin-A activated PBMC, is expressed specifically on a subpopulation of centroblasts and centrocytes of human germinal center (GC) B cells. Burkitt lymphoma (BL) is a tumor consisting of tumor cells with the characteristics of GC B cell. Previously we reported that CM1 ligation with anti-CM1 mAb induced apoptosis in Ramos $(IgM^{high})$ and Raji $(IgM^{low})$ cells. Methods & Results: In the present study, we observed that CM1 ligation with anti-CM1 mAb induced Fas ligand and Fas expression in Ramos cells, but not in Raji cells. Furthermore, anti-Fas blocking antibody, ZB4, blocked CM1-mediated apoptosis effectively in Ramos cells, but not in Raji cells. Increased mitochondrial membrane permeabilization, which was measured by $DiOC_6$, was observed only in Raji cells. In contrast to no significant change of Bax known as pro-apoptotic protein, anti-apoptotic protein Bcl-2 was significantly decreased in Raji cells. In addition, we observed that CM1 ligation increased release of mitochondrial cytochrome c and upregulated caspase-9 activity in Raji cells. Conclusion: These results suggest that apoptosis induced by CM1-ligation is mediated by Fas-Fas ligand interaction in Ramos cells, whereas apoptosis is mediated by down-regulation of Bcl-2 and subsequent decrease of mitochondrial membrane potential in Raji cells.
Lee,Dae-Sil,Kim,Jae Jong,Koh,Sukhoon,Kim,Joong Su The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.2
The N199H variant of the EcoRI endonuclease has about twice the catalytic activity of the wild-type. Aomparison of their biochemical characteristies, usingsynthetic oligonucleotides 5`-dAAAACTTAAGAA-AAAAAAAAA-3`(KA) and 5`-dTTTTTGAATTCT-TTTTTTTTT-3`(KT), helps to define the cleavage reaction pathway of these enzymes. Both EcoRI and EcoRI variant N199H were found to cleave single-stranded KA or KT about three times faster than the double-stranded forms, although the KT oligonucleotide was more susceptible. Using the ssDNA substrate in kinetic analyses, lower Km values were obtained for the N199H variant than for the wild-type at low (50mM), as well as high (200mM), sodium chloride concentrations. This difference between the endonucleases is attributed to a greater accessibility for the substrate by the variant, and also a higher affinity for the DNA backbone. It also appears that the relative activities of the two enzymes,particularly at high ionoc strength,are proportional to their populations in the monomeric enzyme form. That is, according to gel filtration data, half of the N199H molecules exist as monomers in 200 mM NaCl, whereas those of the wild-type are mainly dimeric. Consequently,the Asp199 residue of the EcoRI endonuclease may be implicated in the protein-protein interaction leading to dimerization, as well as in coupling to DNA substrates. In summary, it is proposed that active monomeric endonuclease molecules, derived from the dimeric enzyme, recognize and form a complex with a single stranded form of the DNA substrate, which then undergoes nucleophilic substitution and cleavage.
HSP25 Inhibits Protein Kinase Cδ-mediated Cell Death through Direct Interaction
Lee, Yoon-Jin,Lee, Dae-Hoon,Cho, Chul-Koo,Bae, Sangwoo,Jhon, Gil-Ja,Lee, Su-Jae,Soh, Jae-Won,Lee, Yun-Sil American Society for Biochemistry and Molecular Bi 2005 The Journal of biological chemistry Vol.280 No.18
<P>Heat shock protein 25 (HSP25) interferes negatively with apoptosis through several pathways that involve its direct interaction with cytochrome c or Akt. Here we show that HSP25 inhibits protein kinase C (PKC) delta-mediated cell death through direct interaction. HSP25 binds to kinase-active PKCdelta to inhibit its kinase activity and translocation to the membrane, which results in reduced cell death. Deletion constructs of HSP25 and PKCdelta identified amino acids 90-103 of HSP25 and the C-terminal V5 region of PKCdelta as binding sites. In addition, the interaction between HSP25 and PKCdelta induced HSP25 phosphorylation at Ser-15 and Ser-86, and these phosphorylations permitted HSP25 release from PKCdelta. Based on these observations, we propose that after PKCdelta activation, HSP25 binds to the exposed V5 region of PKCdelta. This novel function of HSP25 accounts for its cytoprotective properties via the inhibition of PKCdelta and the enhancement of HSP25 phosphorylation.</P>
Responses of Nitrogen Oxide to High‐Speed Solar Wind Stream in the Polar Middle Atmosphere
Lee, Ji‐,Hee,Jee, Geonhwa,Kwak, Young‐,Sil,Hong, Sang‐,bum,Hwang, Heejin,Song, In‐,Sun,Lee, Young‐,Sook,Turunen, Esa,Lee, Dae‐,Young American Geophysical Union 2018 JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS Vol.123 No.11
Lee, Dae Sil,Kim, Joong Su,Kim, Jae Jong,Koh, Suk Hoon 생화학분자생물학회 1999 BMB Reports Vol.31 No.2
The N199H variant of the EcoRI endonuclease has about twice the catalytic activity of the wild-type. A comparison of their biochemical characteristics, using synthetic oligonucleotides 5'-dAAAACTTAAGAA-AAAAAAAAA-3' (KA) and 5'-dTTTTTGAATTCT-TTTTTTTTT-3' (KT), helps to define the cleavage reaction pathway of these enzymes. Both EcoRI and EcoRI variant N199H were found to cleave single-stranded KA or KT about three times faster than the double-stranded forms, although the KT oligonucleotide was more susceptible. Using the ssDNA substrate in kinetic analyses, lower K_m values were obtained for the N 199H variant than for the wild-type at low (50 mM), as well as high (200 mM), sodium chloride concentrations. This difference between the endonucleases is attributed to a greater accessibility for the substrate by the variant, and also a higher affinity for the DNA backbone. It also appears that the relative activities of the two enzymes, particularly at high ionic strength, are proportional to their populations in the monomeric enzyme form. That is, according to gel filtration data, half of the N199H molecules exist as monomers in 200 mM NaCl, whereas those of the wild-type are mainly dimeric. Consequently, the Asp199 residue of the EcoRI endonuclease may be implicated in the protein-protein interaction leading to dimerization, as well as in coupling to DNA substrates. In summary, it is proposed that active monomeric endonuclease molecules, derived from the dimeric enzyme, recognize and form a complex with a single stranded form of the DNA substrate, which then undergoes nucleophilic substitution and cleavage.
Effect of calcination temperature on the photocatalytic properties of electrospun TiO2 nanofibers.
Lee, Young-In,Lee, Jong-Sik,Park, Eun-Sil,Jang, Dae-Hwan,Lee, Jae-Eun,Kim, Kahee,Myung, Nosang V,Choa, Yong-Ho American Scientific Publishers 2014 Journal of nanoscience and nanotechnology Vol.14 No.10
<P>In this study, TiO2 nanofibers with a high aspect ratio and a large specific surface area were synthesized using the electrospinning technique, and the effect of calcination temperature on their crystal structure, diameter, specific surface area and photocatalytic activity was systematically investigated. The electrospun, as-prepared PVP/TTIP nanofibers were several tens of micrometers in length with a diameter of 74 nm. TiO2 nanofibers with an average diameter of 50 nm were prepared after calcination at various temperatures. The calcination temperature significantly influenced the photocatalytic and material properties of TiO2 including grain size and specific surface area. When compared to other nanostructured TiO2 materials, such as commercial TiO2 nanoparticles (P25, Degussa), the TiO2 nanofibers exhibited greater photocatalytic activity for the degradation of acetaldehyde and ammonia.</P>