• Tuberculosis and Respiratory Diseases
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• 제46권2호
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• pp.185-194
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• 1999

연구배경: NF-$\kappa$B는 단백질이 생성된 후의 변형(post-translational modification)과 세포내에서의 위치 변화(subcellular localization)에 따라 그 작용이 결정되는 특성을 가진 전사 인자로서 최초에는 면역반응에 있어 중요한 역할을 하는 사실이 알려졌으나 그후 이러한 작용이외에도 급성기 염증 반응, 바이러스의 증식, 세포의 발생과 분화에 있어 중요한 작용을 한다는 사실이 알려지게 되었다. 최근의 연구들에서 NF-$\kappa$B 전사 인자가 정상 세포로부터 암세포로의 형질전환에 있어서도 어떤 기능을 할 것이라는 사실들이 알려지게 되었다. NF-$\kappa$B가 암세포로의 형질 전환, 나아가 암세포의 생성에 어떤 역할을 제공한다면 이러한 사실은 나아가 향후의 암치료에 있어서도 유용한 지식이 될 수 있다. NF-$\kappa$B 전사 인자가 인체 암세포에 있어서 세포의 형질 변환에 연관될 수 있다는 사실은 몇몇 암종에서 알려져 있으나 폐암에서의 NF-$\kappa$B 전사 인자의 종양 생성기능에 있어서는 아직 연구된 바가 없다. 방 법: 본 연구에서는 배양된 인체 폐암세포주에 있어서 NF-$\kappa$B family 전사 인자들의 발현정도를 western blot를 이용하여 관찰하고 과발현된 NF-$\kappa$B 전사 인자의 세포내 위치가 세포핵인지 세포질내에 존재하는 것인지를 각각의 단백질 분획에서 western blot를 시행하여 관찰하였고 또한 immunocy-tochemistry를 시행하여 그 발현 양상을 확인하였다. 존재하는 NF-$\kappa$B 전사 인자가 어떠한 복합체의 형태인지를 알아보기 위하여 세포주의 단백 추출물에서 NF-$\kappa$B family 전사 인자에 대한 항체를 사용하여 immunoprecipitation을 시행하였다. 세포주 단백추출물의 $\kappa$B consensus oligonucleotide에의 결합여부를 보기위하여 electrophoretic mobility shift assay를 시행하였다. 결 과: 배양된 인체 폐암세포주에서는 NF-$\kappa$B family의 p50 subunit, p65 subunit가 발현되어 있었고 p50 subunit의 발현은 세포핵내에 국한하여 위치하고 있음을 western blot와 immunocytochemistry를 통하여 관찰할 수 있었다 immunoprecipitation assay는 세포내에서 p50 subunit가 p65 subunit와 복합체를 이루는 상태로 존재하고 있음을 보여주었다. 폐암세포주의 세포핵 추출물은 NF-$\kappa$B consensus oligonucleotide와 결합할 수 있음을 electrophoretic mobility shift assay를 통하여 확인할 수 있었다. 결 론: 인체 폐암세포주에서 NF-$\kappa$B family 전사 인자의 발현이 활성화되어 있으며 NF-$\kappa$B family 전사 영자가 인체 폐암 형성에 있어 어떤 역할을 할 가능성을 시사한다.

• BMB Reports
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• 제48권1호
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• pp.48-53
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• 2015

Oxidized LDL (oxLDL) performs critical roles in atherosclerosis by inducing macrophage foam cell formation and promoting inflammation. There have been reports showing that oxLDL modulates macrophage cytoskeletal functions for oxLDL uptake and trapping, however, the precise mechanism has not been clearly elucidated. Our study examined the effect of oxLDL on non-muscle myosin heavy chain IIA (MHC-IIA) in macrophages. We demonstrated that oxLDL induces phosphorylation of MHC-IIA (Ser1917) in peritoneal macrophages from wild-type mice and THP-1, a human monocytic cell line, but not in macrophages deficient for CD36, a scavenger receptor for oxLDL. Protein kinase C (PKC) inhibitor-treated macrophages did not undergo the oxLDL-induced MHC-IIA phosphorylation. Our immunoprecipitation revealed that oxLDL increased physical association between PKC and MHC-IIA, supporting the role of PKC in this process. We conclude that oxLDL via CD36 induces PKC-mediated MHC-IIA (Ser1917) phosphorylation and this may affect oxLDL-induced functions of macrophages involved in atherosclerosis.

• BMB Reports
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• 제42권11호
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• pp.758-763
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• 2009

Cancer-associated antigen (CAGE) induces the expression of matrix metalloproteinase-2 (MMP-2) by activating Akt, which in turn interacts with inhibitory kappa kinase $\beta$ ($I{\kappa}K{\beta}$) to activate nuclear factor ${\kappa}B$ (NF-${\kappa}B$). Akt and p38 mitogen activated protein kinase (p38 MAPK) are necessary for CAGE-mediated induction of the AP-1 subunit JunB, whereas extracellular regulated kinase (ERK) is necessary for the induction of fos-related antigen-1 (Fra-1). Induction of MMP-2 by CAGE requires activator of protein-1 (AP-1) to be bound. Specific binding of JunB to MMP-2 promoter sequences was shown by chromatin immunoprecipitation (ChIP) analysis.

• BMB Reports
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• 제33권4호
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• pp.349-352
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• 2000

Proteins that are involved in cellular signal cascade experience phosphorylation and dephosphorylation cycles in their tyrosine residue(s) during cell adhesion. In order to identify the protein(s), which tyrosine desidues are specifically phosphorylated when the cells attached to the substrate, we compared the tyrosine phosphorylation level of proteins between suspension and adhered culture condition in rat fibroblast 3Yl cells. We found that a cluster of 70 kDa protein was specifically phosphorylated when the cells adhered to the substrate, but did not effect the cells held in suspension. The phosphorylated protein is identified as paxillin, a focal adhesion protein in immunoprecipitation and immunobloting analysis. These results suggest that the tyrosine phosphorylation of paxillin may play a role in cell-substrate adhesion.

• BMB Reports
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• 제47권11호
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• pp.643-648
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• 2014

Stanniocalcin (STC), a glycoprotein hormone originally discovered in fish, has been implicated in calcium and phosphate homeostasis. While fishes and mammals possess two STC homologs (STC1 and STC2), the physiological roles of STC2 are largely unknown compared with those of STC1. In this study, we identified Ran-binding protein M (RanBPM) as a novel binding partner of STC2 using yeast two-hybrid screening. The interaction between STC2 and RanBPM was confirmed in mammalian cells by immunoprecipitation. STC2 enhanced the RanBPM-mediated transactivation of liganded androgen receptor (AR), but not thyroid receptor ${\beta}$, glucocorticoid receptor, or estrogen receptor ${\beta}$. We also found that AR interacted with RanBPM in both the absence and presence of testosterone (T). Furthermore, we discovered that STC2 recruits RanBPM/AR complex in T-dependent manner. Taken together, our findings suggest that STC2 is a novel RanBPM-interacting protein that promotes AR transactivation.

• 대한의생명과학회지
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• 제10권4호
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• pp.407-413
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• 2004

Heterotrimeric GTP binding proteins (G proteins) transduce signals of a variety of hormones and neurotransmitters. Go is one of the most abundant G proteins in the brain and classified as the Gi/Go family due to their sequence homology to Gi proteins. While the Gi proteins inhibit adenylyl cyclase and decrease the intracellular cAMP concentration, the functions of Go is not clearly understood despite their sequence homology to Gi. The promeylocytic leukemia zinc finger protein (PLZF) is a DNA binding transcription factor and is expressed highly in central nervous system (CNS). Several studies reported that PLZF may be involved in regulation segmentation/differentiation during CNS development. Here, I report that the alpha subunit of Go (Go ) interacts with PLZF. The interaction between Goa and PLZF was verified by using GST pulldown assay and co-immunoprecipitation. Our findings indicate that Goa could modulate gene expression via interaction with PLZF during neuronal or brain development.

• Journal of Life Science
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• 제12권2호
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• pp.43-46
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• 2002

Kinesin Superfamily Protein 1A (KIF1A) is an anterograde monomeric motor transporting a subset of synaptic vesicle precursors and plays an important role in neuronal function and survival. Here, f have used the yeast two-hybrid system to identify the proteins that interacts with the tail region of KIF1A. Calmodulin was found to interact specifically with the tail region of KIF1A. Calmodulin regulates many diverse cellular functions by modulating the activity of the proteins that interact with it. KIF1A interacts with calmodulin in the yeast two-hybrid assay, which is proved by immunoprecipitation with calmodulin in brain fraction. These results indicate that KIF1A is associated with calmodulin, suggesting that calmodulin may be a key role in the regulation of anterograde transport of synaptic 1 vesicle precursors.

• BMB Reports
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• 제31권1호
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• pp.106-110
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• 1998

We have employed a DNA-native-polyacrylamide gel electrophoresis (DNA-native-PAGE) assay system to characterize the enzyme activity of the endonuclease secreted by human B lymphoblastic IM9 cells. Experimental results clearly demonstrated that the endonuclease activity of IM9 cell culture medium is distinct from that of DNase I in the DNA-native-PAGE assay system. Immunoprecipitation analysis using anti-DNase I antibody showed that the secreted endonuclease is not recognized by the antibody. The secreted endonuclease was estimated using supercoiled plasmid DNA as a substrate. The pH optimum required for the catalytic activity was determined to be in the range of pH 6.6-7.4. No significant difference in the endonuclease secretion was observed by stimulation of the IM9 cells with interferon-${\gamma}$ or interleukin-$1{\beta}$.

• BMB Reports
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• 제42권5호
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• pp.299-303
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• 2009

In this study, we use promoter analysis to show that interaction between Jab1 and p53 induces suppression of p53 activation in U2OS and H1299 cells. Interaction between p53 and Jab1 was further confirmed by immunoprecipitation and immunofluorescent analyses. In particular, Jab1 was able to induce nuclear export of p53 as previously reported. When Jab1 was overexpressed in U2OS cells followed by etoposide or hydrogen peroxide ($H_2O_2$), cell death induced by such stresses was protected against. On the contrary, when the level of Jab1 was suppressed in U2OS cells, cytotoxicity imposed by etoposide and $H_2O_2$ was dramatically increased, suggesting a cell protective role for Jab1. These results indicate that Jab1 is a negative regulator of p53 and a plausible oncogene.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.122-128
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• 1992

Post-translational modifications of the nucleocapsid protein of bovine coronavirus (Quebec strain) were investigated. Coronavirions were radiolabelled in vivo with inorganic $[^{32}P]$orthophosphate and analysed by SDS-PAGE, followed by autoradiography. A single polypeptide with a migration rate of 55 KDa was identified by metabolic phosphate labelling, demonstrating that the nucleocapsid protein of bovine coronavirus was a phosphoprotein. A gene encoding the nucleocapsid protein was inserted immediately downstream from the polyhedrin promoter of Autographa californica nuclear polyhedrosis baculovirus. Spodoptera frugiperda cells infected with this recombinant baculovirus synthesized a 55 KDa polypeptide, as demonstrated by immunoprecipitation with anti-nucleocapsid monoclonal antibody. The recombinant nucleocapsid protein synthesized in Spodoptera cells could also be labelled by $[^{32}P]$orthophosphate. Phosphoamino acid analysis showed that both serine and threonine residues were phosphorylated in authentic, as well as in recombinant nucleocapsid proteins, with a relative phosphorylation ratio of 7:3. Our studies demonstrated that the nucleocapsid protein of bovine coronavirus was a serine and threonine-phosphorylated protein and that Spodoptera insect cells were able to properly phosphorylate the relevant foreign proteins.