• 생명과학회지
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• 제19권11호
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• pp.1529-1537
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• 2009

L-arginine 구조유사체인 L-canavanine의 인체 급성백혈병 Jurkat T 세포에 대한 apoptosis 유도활성이 단백질 티로신키나아제 $p56^{lck}$에 어떻게 조절되는지를 규명하기 위해 $p56^{lck}$를 발현하는 Jurkat T 세포주 E6.1과 $p56^{lck}$-결손 Jurkat T 세포주 JCaM1.6에 있어서 L-canavanine의 세포독성, L-canavanine에 의해 유도되는 apoptotic DNA fragmentation 및 apoptotic sub-$G_1$ peak를 비교하여 본 바, $p56^{lck}$-negative JCaM1.6 세포가 $p56^{lck}$-positive E6.1 세포에 비해 L-canavanine의 apoptotis 유도활성에 훨씬 더 민감한 것으로 나타났다. 이러한 $p56^{lck}$-negative JCaM1.6 세포의 민감성은 JCaM1.6 세포에 $p56^{lck}$ 유전자를 transfection시켜 발현시키면 현저히 감소되었다. L-Canavanine에 의해 유도되는 apoptosis관련 현상들을 $p56^{lck}$-stable transfectant인 JCaM1.6/lck 세포와 empty vector-transfectant 인 $p56^{lck}$-negaive JCaM1.6/vector 세포에서 Western blot analysis로 비교한 결과, L-canavanine에 의해 유도되는 mitochondrial membrane potential (${\Delta\Psi}m$)의 감소, caspase-9, -8, -7 및 -3의 활성화, 그리고 PARP 및 $PLC{\gamma}$-1의 분해가 JCaM1.6/vector 세포에 비해 JCaM1.6/lck 세포에서 더 약하게 나타났다. JCaM1.6/lck 세포를 2.5 mM L-canavanine으로 처리한 다음 세포 내 $p56^{lck}$ kinase 활성의 변화를 $\alpha$-casein을 기질로 하여 시간 별로 측정한 결과, L-canavanine의 처리 후 15분만에 $p56^{lck}$ kinase의 활성이 약 1.6배 증가되었으며 이후 6시간 동안은 약 1.3~1.4 배정도 증가된 수준으로 kinase 활성이 유지되는 것으로 확인되었다. L-Canavanine에 의한 apoptosis의 개시에 Fas/FasL 상호작용이 관련되는지를 규명하기 위해 FADD-negative Jurkat T 세포주 I2.1, caspase-8-negative Jurkat T 세포주 I9.2 및 wild-type Jurkat T 세포주 A3에 대한 L-canavanine의 세포독성을 비교한 결과, A3와 I2.1 세포의 경우는 L-canavanine의 세포독성이 동일하게 나타났고, 특히 caspase-8가 결손된 I9.2 세포의 경우는 L-canavanine의 세포독성에 대한 민감성이 A3와 I2.1 세포에 비해 단지 미약하게만 완화되는 것으로 나타나, L-canavanine의한 apoptosis에는 Fas/FasL 상호작용이 관련되어 있지 않으며, 또한 caspase-8의 역할이 필수적이지 않음을 시사하였다. Jurkat T 세포에 있어서 L-canavanie에 의해 유도되는 sub-$G_1$ peak 및 caspases 활성화에 미치는 pan-caspase inhibitor (z-VAD-fmk), caspase-9 inhibitor (z-LEHD-fmk), caspase-3 inhibitor (z-DEVD-fmk), caspase-4 inhibitor (z-LEVD-fmk) 및 caspase-12 inhibitor (z-ATAD-fmk)의 영향을 조사한 결과, L-canavanie에 의한 apoptosis는 ${\Delta\Psi}m$의 감소, caspase-9 및 caspase -3의 활성화에 뒤따른 caspase-8 및 caspase-7의 활성화, 그리고 PARP의 분해의 순서로 유도되는 것으로 나타났으며, 아울러 caspase-9의 활성화와 함께 caspase-12의 활성화가 L-canavanine 처리에 따른 caspase-3의 활성화에 요구되는 것으로 확인되었다. 결론적으로, L-canavanine 처리에 의한 Jurkat T 세포의 apoptosis는 ${\Delta\Psi}m$ 감소, caspase-9, caspase-3 및 caspase-7의 활성화에 의해 유도되며, 이들 apoptosis 현상들은 $p56^{lck}$에 의해 negative regulation되었다.

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.266-272
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• 2006

Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were developed for 67 molecules of 2-amino-benzothiazole-6-anilide derivatives against lymphocyte-specific protein tyrosine kinase (P56 LCK). The molecular field analysis (MFA) and receptor surface analysis (RSA) were employed for QSAR studies and the predictive ability of the model was validated by 15 test set molecules. Structure-based investigations using molecular docking simulation were performed with the crystal structure of P56 LCK. Good correlation between predicted fitness scores versus observed activities was demonstrated. The results suggested that the nature of substitutions at the 2-amino and 6-anilide positions were crucial in enhancing the activity, thereby providing new guidelines for the design of novel P56 LCK inhibitors.

• BMB Reports
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• 제42권1호
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• pp.35-40
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• 2009

Protein kinase D2 (PKD2) is a member of the PKD serine/threonine protein kinase family that has been implicated in the regulation of a variety of cellular processes including proliferation, survival, protein trafficking and immune response. In the present study, we report a novel interaction between PKD2 and Lck, a member of the Src tyrosine protein kinase family that is predominantly expressed in T cells. This interaction involved the C-terminal kinase domains of both PKD2 and Lck. Moreover, co-expression of Lck enhanced the tyrosine phosphorylation of PKD2 and increased its kinase activity. Finally, we report that PKD2 enhanced T cell receptor (TCR)-induced nuclear factor of T cell (NFAT) activity in Jurkat T cells. These results suggested that Lck regulated the activity of PKD2 by tyrosine phosphorylation, which in turn may have modulated the physiological functions of PKD2 during TCR-induced T cell activation.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.81-81
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• 1995

It is well known that Src Homology 2(SH2) domain in many intracellular signal transduction proteins is very important. The domain has about 100 amino acid residues and bind phosphotyrosine-containing peptide with high affinity and specificity. Lck SH2 domain is a Src-like, lymphocyte-specific tyrosine kinase. An 11-residue phosphopeptide derived from the hamster polvoma middle-T antigen, EPQp YEEIPIYL, binds with an 1 nM dissociation constant to Lck SH2 domain. And it is known that the phosphotyrosine and isoleucine residues of the peptide are tightly bound by two well-defined pockets on Lck SH2 domain's surface. To investigate the conformational changes during complexation of SH2 domain with phosphopeptide we have performed the molecular dynamics simulation for Lck SH2 domain with peptide and peptide-free form at look in aqueous solution. More than 3000 water molecules were incorporated to solvate Lck SH2 domain and peptide. Periodic boundary condition has been applied in molecular dynamics simulation. Data analysis with the results of that simulation shows that the phosphopeptide makes primary interaction with the Lck SH2 domain at six central residues, The comparison of the complexed and uncomplexed SH2 domain structures in solution has revealed only relatively small change. But the hydrophilic and hydrophobic pockets in the protein surface show the conformational changes in spite of the small structural difference between the complex and peptide-free forms.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.200-206
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• 2007

Pharmacophore models for lymphocyte-specific protein tyrosine kinase (P56 LCK) were developed using CATALYST HypoGen with a training set comprising of 25 different P56 LCK inhibitors. The best quantitative pharmacophore hypothesis comprises of one hydrogen bond acceptor, one hydrogen bond donor, one hydrophobic aliphatic and one ring aromatic features with correlation coefficient of 0.941, root mean square deviation (RMSD) of 0.933 and cost difference (null cost-total cost) of 66.23. The pharmacophore model was validated by two methods and the validated model was further used to search databases for new compounds with good estimated LCK inhibitory activity. These compounds were evaluated for their binding properties at the active site by molecular docking studies using GOLD software. The compounds with good estimated activity and docking scores were evaluated for physiological properties based on Lipinski's rules. Finally 68 compounds satisfied all the properties required to be a successful inhibitor candidate.

• 한국가축번식학회지
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• 제26권4호
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• pp.347-351
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• 2002

Transgenes in HSY-TK gene driven by the lck promoter was tested for the expression in immune cells (Jurkat cells) to apply xenotransplantation of human cells into transgenic animals for the potential use of the proliferation or differentiation of human stem cells in the large animal such as an pig. Also, lck-CFP gene was used for transfection experiment into Jurkat cell to confirm the proper regulation of lck promoter for transgene expression in the T cells. Transfection of lck-GFP gene into Jurkat ceils induced CFP expression in transfected cells. The expression of Ick-TK and Ick-CFP genes was confirmed by RT-PCR using RNAs extracted from Jurkat cells, When Jurkat cells transfected with TK and CFP genes were selected against G418 or gancyclovir treatments, Jurkat cells transfected with TK gene were not proliferated in G4i8 and gancyclovir medium while intact cells or cells transfected with CFP gene could grow in gancyclovir medium. However, Jurkat cells transfected with TK or GFP gene were proliferated in G418 medium probably due to Neo$^{r}$ gene in the vector. Gancyclovir treatment destroyed Jurkat cells expressing TK gene indicating that T-cells expressing TK gene can be selectively eliminated by TK gene expression driven by lck promoter.

• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.664-666
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• 2003

• 한국가축번식학회지
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• 제27권3호
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• pp.225-231
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• 2003

본 연구는 생체 내 세포 및 조직배양기로서의 면역결핍동물을 개발할 목적으로 proximal lck promoter와 DT-A gene를 이용하여 형질전환생쥐을 생산하고 이 형질전환생쥐의 면역세포에서 DT-A gene이 발현되는지를 분석하였다. 형질전환생쥐와 정상생쥐로부터 thymus, spleen 및 liver에서 RNA를 추출하여 RT-PCR수행하였는데 정상생쥐의 조직에서는 어떠한 DT-A gene의 발현양상을 얻을 수 없었으나 형질전환생쥐의 thymus, spleen, liver에 DT gene의 발현을 확인할 수 있었고, Northern blotting을 이용하여 형질전환생쥐의 thymus, spleen 및 liver에서 DT-A gene이 강하게 발현되는 것으로 나타났다. 형질전환생쥐 $F_1$ 및 $F_2$ 산자의 혈액에서 T-cell 발달의 분포도를 확인하기 위해 CD4 및 CD8 antibody를 이용하여 FACS analysis를 실시하였는데 형질전환생쥐의 혈액 내 mature T-cell인 single positive thymocyte의 수가 정상생쥐에 비해 감소하는 경향을 나타냈다. 정상생쥐의 혈액 내 T-cell 중 $CD8^{+}$ T-cell의 경우 약 50%를 나타냈으나 형질전환생쥐의 경우 33%로 감소하였고, $CD4^{+}$ T-cell은 정상생쥐에서 10%를 차지하고 있으나 형질전환생쥐에서는 5.9%로 감소되는 것으로 분석되었다. 그러므로 본 연구의 형질전환생쥐에서 lck promoter에 의해 초기 immature한 상태의 T-cell에서 DT-A gene이 발현되어 발육중인 T-cell이 파괴 되어 mature 상태인 $CD4^{+}CD8^{-}$나 $CD4^{-}CD8^{+}$ cells (single-positive)들이 감소된 것으로 확인되었다.

• BMB Reports
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• 제41권8호
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• pp.575-580
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• 2008

Thymocyte-specific transcriptional regulatory systems can be used to better understand the relationship between transcription and V(D)J recombination during early T cell development. In this study, we generated transgenic mice expressing the transactivator Gal4-VP16 or the Gal4 DNA binding domain (Gal4-DBD) under the control of the lck proximal promoter, which is only active in immature thymocytes. From these studies Gal4-VP16 and Gal4-DBD expression was shown to significantly alter thymic cellularity and differentiation without significantly changing the $CD3^+$ thymocyte distribution. Furthermore, the presence of Gal4-VP16 or Gal4-DBD in the transgenic thymocytes retarded the mobility of the Gal4 DNA binding motif as determined by a gel mobility shift assay, suggesting that the developmental alteration did not affect the functional property of the transgenic proteins. These results indicated that lck promoter-driven Gal4-VP16 or Gal4-DBD expression did not affect $CD3^+$ mature thymocytes, thus this system can be applied to study transcriptional regulation of transresponder genes in bigenic mouse model thymocytes.

• BMB Reports
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• 제31권4호
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• pp.370-376
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• 1998

Src-Homology 2 (SH2) domains have a capacity to bind phosphotyrosine-containing sequence context and play essential roles in various cellular signaling pathways. Due to the specific nature of the binding between SH2 domains and their counterpart proteins, inhibitors of SID domain binding have drawn extensive attention as a potential candidate for therapeutic agents. Here, we describe the binding assay system to screen for the ligands or blockers of the SH2 domains with an emphasis on the $p56^{lck}$ SH2 domain. In our assay system, SID domains expressed and purified as fusion proteins to Glutathione-S-transferase (GST) were covalently attached to 96-well microtitre plates through amide bond formation, which were subsequently allowed to bind the biotinylated phosphotyrosine (pY)containing synthetic pep tides. The binding of biotinylated pY peptides was detected by the horseradish peroxidase (HRP)-conjugated streptavidin. Using the various combinations of SH2 domain-pY peptides, we observed that: (1) The binding of pY-peptides to its counterpart SH2 domain is concentration-dependent and saturable; (2) The binding is highly specific for a particular combination of SH2 domain-pY peptide pair; and (3) The binding of Lck SH2-cognate pY-peptides is specifically competed by the nonbiotinylated peptides with expected relative affinity. These results indicate that the established assay system detects the SH2-pY peptide interaction with reproducible sensitivity and specificity and is suitable for screening the specific inhibitors of $p56^{lck}$ SH2 function.