• 대한의생명과학회지
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• 제12권4호
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• pp.405-411
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• 2006

Heterotrimeric GTP binding proteins (G proteins) mediate signal transduction generated by neurotransmitter and hormones. Among G-proteins, Go is classified as a member of the Go/Gi family and the most abundant heterotrimeric G protein in brain. Most of the mechanistic analyses on the activation of Go indicated its action to be mediated by the $G{\beta}{\gamma}$ dimer because downstream effectors for its ${\alpha}$ subunit have not been clearly defined. To determine the downstream effectors of alpha subunits of Go ($Go{\alpha}$), we used yeast two-hybrid system to screen $Go{\alpha}$ interacting partners in cDNA library from the human brain. A brain specific high mobility group box containing protein (BHX), A possible transcription factor, was identified as a $Go{\alpha}$ interacting protein. We confirmed interaction between $Go{\alpha}$ and BHX employing in vitro affinity binding assay. Moreover, active form of $Go{\alpha}$ preferentially interacts with BHX than inactive farm. Our findings indicate that $Go{\alpha}$ could modulate gene expression via interaction with BHX during neuronal or brain development.

• BMB Reports
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• 제33권1호
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• pp.59-62
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• 2000

Hepatitis C virus (HCV) nonstructural 5B (NS5B) protein is an RNA-dependent RNA polymerase (RdRp). To determine whether it can contribute to viral replication by interaction with cellular proteins, the yeast two-hybrid screening system was employed to screen a human liver cDNA library. Using the HCV NS5B as a bait, we have isolated positive clones encoding a cellular protein. The NS5B interacting protein, 5BIP, is a novel cellular protein of 170 amino acids. Interaction of the HCV NS5B protein with 5BIP was confirmed by a protein-protein blotting assay. Recently, we have demonstrated that NS5B possesses an RdRp activity and thus it is possible that 5BIP, in association with NS5B, plays a role in HCV replication.

• 대한의생명과학회지
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• 제9권2호
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• pp.105-110
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• 2003

Ankyrins are a ubiquitously expressed family of intracellular adaptor proteins involved in targeting diverse proteins to specialized membrane domains in both the plasma membrane and the endoplasmic reticulum. Canonical ankyrins are 190-220 kDa proteins expressed in most tissues and cell types and comprise a membrane-binding domain (MBD) of 24 ANK repeats, a spectrin-binding domain, a death domain and a C-terminal domain. Rescue studies with ankyrin-B/G chimeras have identified the C-terminal domain of ankyrin-B as the defining domain in specifying ankyrin-B activity, but the function of C-terminal domain of ankyrin-B is, however, not known. We report here that the C-terminal domain of ankyrin-B is capable of interacting with the C-terminal Region of Hsp40. The Hsps are induced not only by heat shock but also by various other environmental stresses. Hsps are also expressed constitutively at normal growth temperatures and have basic and indispensable functions in the life cycle of proteins as molecular chaperones, as well as playing a role in protecting cells from the deleterious stresses. The binding sites required in the interaction between C-terminal domain of ankyrin-B and C-terminal region of Hsp40 were characterized using the yeast two-hybrid system and GST-pull down assay. The interaction between ankyrin-B and Hsp40 represents the first direct evidence of ankyrin's role as chaperones.

• 생명과학회지
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• 제19권8호
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• pp.1055-1061
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• 2009

${\alpha}$-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) 수용체는 중추신경계에 널리 발현하며, 연접부위에서 글루타메이트에 의한 흥분성 신경전달의 역할을 행한다. 이러한 수용체의 조절은 학습과 기억에 관여한다. 본 연구에서는 AMPA receptor subunit glutamate receptor-interacting protein 1 (GRIP1)과 결합하는 단백질로 armadillo family인 p0071/plakophilin-4을 분리하였다. GRIPl 단백질은 p0071/plakophilin-4 단백질의 C-말단과 결합하며, armadillo family 단백질 중 p0071/plakophilin-4 과만 결합한다. 효모 two-hybrid assay에서 GRIPl의 Postsynaptic density-95/Discs large/Zona occludens-1 (PDZ) 영역이 p0071/plakophilin-4 단백질과의 결합에 관여하며, p0071/plakophilin-4 단백질의 C-말단 아미노산인 "S-X-V" 배열이 결합에 필수적이었다. 이러한 결합은 뇌 균질액에서 Glutathione S-transferase (GST) pull-down assay와 공면역침강법으로 확인하였다. 이러한 결과들은 AMPA 수용체가 연접후막에 안정적으로 위치하는 새로운 역할을 시사한다.

• Parasites, Hosts and Diseases
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• 제44권4호
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• pp.303-312
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• 2006

Interactions between GRA proteins of dense granules in Toxoplasma gondii and host cell proteins were analyzed by yeast two-hybrid technique. The cMyc-GRA fusion proteins expressed from pGBKT7 plasmid in Y187 yeast were bound to host cell proteins from pGADT7-Rec-HeLa cDNA library transformed to AH109 yeast by mating method. By the selection procedures, a total of 939 colonies of the SD/-AHLT culture, 348 colonies of the $X-\alpha-gal$ positive and PCR, 157 colonies of the $X-\beta-gal$ assay were chosen for sequencing the cDNA and finally 90 colonies containing ORF were selected to analyze the interactions. GRA proteins interacted with a variety of host cell proteins such as enzymes, structural and functional proteins of organellar proteins of broad spectrum. Several specific bindings of each GRA protein to host proteins were discussed presumptively the role of GRA proteins after secreting into the parasitophorous vacuoles (PV) and the PV membrane in the parasitism of this parasite.

• The Korean Journal of Physiology and Pharmacology
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• 제8권3호
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• pp.167-172
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• 2004

The kinesin proteins (KIFs) make up a large superfamily of molecular motors that transport cargo such as vesicles, protein complexes, and organelles. KIF5 is a heterotetrameric motor that conveys vesicles and plays an important role in neuronal function. Here, we used the yeast two-hybrid system to identify the neuronal protein(s) that interacts with the tail region of KIF5 and found a specific interaction with ${\beta}III$ spectrin. The amino acid residues between 1394 and 1774 of ${\beta}III$ spectrin were required for the interaction with KIF5C. ${\beta}III$ spectrin also bound to the tail region of neuronal KIF5A and ubiquitous KIF5B but not to other kinesin family members in the yeast two-hybrid assay. In addition, these proteins showed specific interactions, confirmed by GST pull-down assay and co-immunoprecipitation. ${\beta}III$ spectrin interacted with GST-KIF5 fusion proteins, but not with GST alone. An antibody to ${\beta}III$ spectrin specifically co-immunoprecipitated KIF5s associated with ${\beta}III$ spectrin from mouse brain extracts. These results suggest that KTF5 motor proteins transport vesicles or organelles that are coated with ${\beta}III$ spectrin.

• Parasites, Hosts and Diseases
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• 제46권4호
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• pp.209-216
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• 2008

A monoclonal antibody against Toxoplasma gondii of Tg556 clone (Tg556) blotted a 29 kDa protein, which was localized in the dense granules of tachyzoites and secreted into the parasitophorous vacuolar membrane (PVM) after infection to host cells. A cDNA fragment encoding the protein was obtained by screening a T. gondii cDNA expression library with Tg556, and the full-length was completed by 5'-RACE of 2,086 bp containing an open reading frame (ORF) of 669 bp. The ORF encoded a polypeptide of 222 amino acids homologous to the revised GRA3 but not to the first reported one. The polypeptide has 3 hydrophobic moieties of an N-terminal stop transfer sequence and 2 transmembrane domains (TMD) in posterior half of the sequence, a cytoplasmic localization motif after the second TMD and an endoplasmic reticulum (ER) retrival motif in the C-terminal end, which suggests GRA3 as a type III transmembrane protein. With the ORF of GRA3, yeast two-hybrid assay was performed in HeLa cDNA expression library, which resulted in the interaction of GRA3 with calcium modulating ligand (CAMLG), a type II transmembrane protein of ER. The specific binding of GRA3 and CAMLG was confirmed by glutathione S-transferase (GST) pull-down and immunoprecipitation assays. The localities of fluorescence transfectionally expressed from GRA3 and CAMLG plasmids were overlapped completely in HeLa cell cytoplasm. In immunofluorescence assay, GRA3 and CAMLG were shown to be co-localized in the PVM of host cells. Structural binding of PVM-inserted GRA3 to CAMLG of ER suggested the receptor-ligand of ER recruitment to PVM during the parasitism of T. gondii.

• 생명과학회지
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• 제21권4호
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• pp.613-615
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• 2011

ERp29는 endoplasmic reticulum (ER) lumen에 존재하는 단백질로 protein disulfide isomerase (PDI) family에 속한다. 비록 관련 연구 결과는 조금 있지만 정확한 생물학적인 기능은 아직 분명하지 않지만, 분비단백질과정과 단백질 folding에 관여하는 것으로 알려 지고 있다. ERp29의 기능 연구를 위하여 yeast two-hybrid screening/GST pull-down assay방법을 사용하여 ERp29-결합단백질인 ADP-ribosylation factor 5 (ARF5)를 동정하였다. 이들의 결합은 정상적인 세포생리상태에서는 결합하지만 ER stress 상태에서는 떨어졌다. 이 결과는 ERp29의 기능 연구를 위하여 하나의 실마리를 제공할 것이다.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.45-45
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• 2003

We isolated a novel ankyrin-repeat containing protein, rSIAP (rSlo Interacting Ankyrin-repeat Protein), as an interacting protein to the cytosolic domain of the alpha-subunit of rat large-conductance Ca$\^$2+/-activated K$\^$+/ channel (rSlo) by yeast two-hybrid screening. Affinity pull-down assay showed the direct and specific interaction between rSIAP and rSlo domain. The channel-binding proteins can be classified into several categories according to their functional effects on the channel proteins, i.e. signaling adaptors, scaffolding net, molecular tuners, molecular chaperones, etc. To obtain initial clues on its functional roles, we investigated the cellular localization of rSIAP using immunofluorescent staining. The results showed the possible co-localization of rSlo and rSIAP protein near the plasma membrane, when co-expressed in CHO cells. We then investigated the functional effects of rSIAP on the rSlo channel using electrophysiological means. The co-expression of rSIAP accelerated the activation of rSlo channel. These effects were initiated at the micromolar [Ca$\^$2+/]$\_$i/ and gradually increased as [Ca$\^$2+/]$\_$i/ raised. Interestingly, rSIAP decreased the inactivation kinetics of rSlo channel at micromolar [Ca$\^$2+/]$\_$i/, while the rate was accelerated at sub-micromolar [Ca$\^$2+/]$\_$i/. These results suggest that rSIAP may modulate the activity of native BK$\_$Ca/ channel by altering its gating kinetics depending on [Ca$\^$2+/]$\_$i/. To localize critical regions involved in protein-protein interaction between rSlo and rSIAP, a series of sub-domain constructs were generated. We are currently investigating sub-domain interaction using both of yeast two-hybrid method and in vitro binding assay.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2002년도 추계학술대회
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• pp.76-78
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• 2002

Heat shock proteins (HSPs) are induced in most living cells by mild heat treatment, ethanol, heavy metal ions and hypoxia. In yeast Saccharomyces cerevisiae, mild heat pretreatment strongly induces Hsp104 and thus provide acquired thermotolerance. The ability of hsp104 deleted mutant $({\triangle}hsp104)$ to acquire tolerance to extreme temperature is severely impaired. In providing thermotolerance, two ATP binding domains are indispensible, as demonstrated in ClpA and ClpB proteases of E. coli. The mechanisms by which Hsp104 protects cells from severe heat stress are not yet completely elucidated. We have investigated regulation of mitochondrial metabolic pathways controlled by the functional Hsp104 protein using $^{13}C_NMR$ spectroscopy and observed that the turnover rate of TCA cycle was enhanced in the absence of Hsp104. Production of ROS, which are toxic to kill cells radiply via oxidative stress, was also examined by fluorescence assay. Mitochondrial dysfunction was manifested in increased ROS levels and higher sensitivity for oxidative stress in the absence of Hsp104 protein expressed. Finally, we have identified mitochondrial complex I and Ferritin as binding protein(s) of Hsp104 by yeast two hybrid experiment. Based on these observations, we suggest that Hsp104 protein functions as a protector of oxidative stress via either keeping mitochondrial integrity, direct binding to mitochonrial components or regulating metal-catalyzed redox chemistry.