• 한국동물위생학회지
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• 제28권4호
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• pp.393-405
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• 2005

In prion pathogenesis, the structural conversion of the cellular prion protein $(PrP^c)$ to its abnormal isomer $(PrP^{Sc})$ is believed to be a major event. The susceptibility or resistance to natural sheep scrapie is associated with polymorphisms of host PrP gene (PRNP) at amino acid residues 136, to a lesser extent 154. The 112 residue in ovine PrP displays a natural polymorphism, Methionine to Threonine, which has not been thoroughly investigated. However the cell-free conversion assay showed that ARQ with Thr112 $(T_{112}ARQ)^{1)}$ presents lower convertibility to $PrP^{Sc}$than wild type ARQ $(M_{112}ARQ)$ [1] In this study we generated ovine recombinant PrPs of 112 allelic variants by metal chelate affinity chromatography and cation exchange chromatography. The final purity of the ovine PrP ARQ was more than $95\%$. These variants showed similar immunoreactivity against anti-PrP monoclonal antibodies in Western blot and ELISA. The refolded $M_{112}ARQ$ and $M_{112}ARQ$ presented the secondary structural content to similar extent via CD spectroscopy analysis. The inherited structural features of $M_{112}ARQ$ and $M_{112}ARQ$ under the different biophysical conditions are in the middle of investigation.

• Journal of Microbiology and Biotechnology
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• 제27권5호
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• pp.1023-1031
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• 2017

The conformational change of cellular prion protein ($PrP^C$) to its misfolded counterpart, termed $PrP^{Sc}$, is mediated by a hypothesized cellular cofactor. This cofactor is believed to interact directly with certain amino acid residues of $PrP^C$. When these are mutated into cationic amino acid residues, $PrP^{Sc}$ formation and prion replication halt in a dominant negative (DN) manner, presumably due to strong binding of the cofactor to mutated $PrP^C$, designated as DN PrP mutants. Previous studies demonstrated that plasminogen and its kringle domains bind to PrP and accelerate $PrP^{Sc}$ generation. In this study, in vitro binding analysis of kringle domains of plasminogen to Q167R DN mutant PrP (PrPQ167R) was performed in parallel with the wild type (WT) and Q218K DN mutant PrP (PrPQ218K). The binding affinity of PrPQ167R was higher than that of WT PrP, but lower than that of PrPQ218K. Scatchard analysis further indicated that, like PrPQ218K and WT PrP, PrPQ167R interaction with plasminogen occurred at multiple sites, suggesting cooperativity in this interaction. Competitive binding analysis using $\small{L}$-lysine or $\small{L}$-arginine confirmed the increase of the specificity and binding affinity of the interaction as PrP acquired DN mutations. Circular dichroism spectroscopy demonstrated that the recombinant PrPs used in this study retained the ${\alpha}$-helix-rich structure. The ${\alpha}$-helix unfolding study revealed similar conformational stability for WT and DN-mutated PrPs. This study provides an additional piece of biochemical evidence concerning the interaction of plasminogen with DN mutant PrPs.

• 한국미생물·생명공학회지
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• 제43권2호
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• pp.91-96
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• 2015

Prion은 양의 scrapie, 소의 bovine spongiform encephalopathy와 사람의 CJD와 같은 다양한 신경 퇴행성 질환을 유발시키는 단백질 병원체이다. 정상 prion 단백질인 PrP^C가 병원성 PrP^Sc로 바뀌는 과정에 대해서는 많은 연구가 진행되었고, PrP^Sc로의 단백질 구조 변화가 다양한 환경적 요소에 의해서 영향 받는 것으로 추측된다. 바다조류로부터 분리된 MAAs는 다양한 스트레스 환경에서 조류를 보호해주는 것으로 알려져 있다. 이와 같은 사실에 기초하여 mycosporineglycine, porphyra-334와 shinorine 3종의 MAAs로 처리한 prion 감염 신경세포 주에서 prion 단백질 축적의 변화를 평가하였다. PK 저항성을 갖는 PrP^Sc를 western blot 방법으로 확인한 결과, MAA에 의해서 PrP^Sc 단백질의 증식을 관찰하였다.

• 한국발생생물학회지:발생과생식
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• 제28권2호
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• pp.29-36
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• 2024

Cellular prion protein (PrP^C) encoded at Prnp gene is well-known to form a misfolded isoform, termed scrapie PrP (PrP^SC) that cause transmissible degenerative diseases in central nervous system. The physiological role of PrP^C has been proposed by many studies, showing that PrP^C interacts with various intracellular, membrane, and extracellular molecules including mitochondrial inner membrane as a scaffold. PrP^C is expressed in most cell types including reproductive organs. Numerous studies using PrP^C knockout rodent models found no obvious phenotypic changes, in particular the clear phenotypes in development and reproduction have not demonstrated in these knockout models. However, various roles of PrP^C have been evaluated at the cellular levels. In this review, we summarized the known roles of PrP^C in various cell types and tissues with a special emphasis on those involved in reproduction.

• 한국인터넷방송통신학회논문지
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• 제10권5호
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• pp.113-119
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• 2010

본 논문에서는 한 쌍의 1차 사용자 송 수신단(PT-PR)과 한 쌍의 2차 사용자 송 수신단(ST-SR)을 가지는 무선 인지 통신 시스템을 고려한다. 첫 번째 시간 슬롯(1 Phase)에서 1차 사용자 송신단(Primary Transmitter : PT)은 1차 사용자 수신단(Primary Receiver : PR), 2차 사용자 송신단(Secondary Transmitter : ST) 및 2차 사용자 수신단(Secondary Receiver : SR)에 자신의 신호 $x_p$를 브로드캐스트하며, 각각의 수신단(PR, ST, SR)에서는 수신된 신호를 복호한다. 두 번째 시간 슬롯(2 Phase)에서 ST는 수신 후 복호한 ${x_p}^{\prime}$와 자신이 전송하고자하는 신호 $x_s$를 결합하여 PR과 SR에 브로드캐스트하고, 각 수신단(PR, SR)에서는 수신한 신호를 복호한다. 이 때 PR은 첫 번째 시간 슬롯에 수신한 $x_p$와 두 번째 시간 슬롯에 수신한 $x_p+x_s$ 신호 중 $x_p$를 검출하여 최대 비 결합(Maximal Ratio Combining) 기법을 이용하여 결합한다. 이 때 PR에서는 다이버시티 이득을 얻을 수 있다. SR은 첫 번째 시간 슬롯에 수신한 $x_p$와 두 번째 시간 슬롯에 수신한 $x_p+x_s$신호를 가지고 선형결합을 통해 $x_s$를 얻는다.

• 한국식품과학회지
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• 제34권4호
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• pp.710-718
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• 2002

콩과 식물인 갈근에는 genistein과 daidzein이 함유된 것으로 알려졌으므로 본 연구는 갈근(PR), 갈화(PF) 및 어린순인 갈용(PL)에 함유된 phytoestrogen의 함량을 HPLC법으로 정량 분석하였다. 동시에 phytoestrogen의 골다공증 치료제에 대한 효능 검색의 일환으로 조골세포의 증식작용(MTT법 및 ALP분석)과 피골세포의 활성(TRAP법)을 측정하였고 난소절제 흰쥐에 PR 1 g/kg/day(PR-1) 및 PR 5 g/kg/day(PR-5)을 9주 동안 투여한 후 혈액분석, 혈장 Alkaline phospatase(ALP), 칼슘, 무기성 인산염, 총콜레스테롤, LDL- 및 HDL-콜레스테롤을 측정하였고 적출된 경골 및 요추골의 소주골면적을 측정하였다. PR과 PF의 총 daidzein의 함량은 $10436{\pm}2144\;mg/kg$와 $1003{\pm}206\;mg/kg$이었고 genistein과 formononetin은 PR에만 존재하고 PF 및 PL에는 함유되어 있지 않았다. 인간 유사 조골 세포주인 Saos-2에 PR은 대조군의 158% 정도(5 mg/mL)의 세포증식효과와 ALP 활성을 증가시켰으나 전처리한 PR, PF 및 PL의 세포증식효과는 없었고 PL만이 ALP 활성을 증가시켰다. 파골세포의 증식억제실험에서 genistein의 $IC_{50}$는 $1.57{\times}10^{-4}\;mg/mL$ $(5.81{\times}10^{-7}\;M)$이었고, daidzein과 PR은 효과가 없었다. 난소절제 흰쥐에 대한 in vivo 실험에서 대조군이 sham군보다 난소적출 1주 후부터 체중의 증가가 급격하게 나타났으나 PR의 투여로 둔화되었다. PR 투약에 의한 자궁의 무게는 PR-5군은 대조군에 비해 증가되었고(p<0.05), PR-1군은 대조군과 유의성이 없었다. 혈장 ALP의 활성은 주령의 증가에 EK라 감소하는 경향을 보였고, HDL-콜레스테롤의 농도는 모든 군에서 주령에 따라 감소되었으나(p<0.01), PR-5군의 LDL-콜레스테롤의 농도는 대조군에 비해 감소되었다(p<0.01). 대조군에 비해 sham군의 경골 및 요추골의 면적은 증가되었고(p<0.01), PR 투여군(PR-1 및 PR-5)도 sham보다 적으나 대조군에 비해 소주골 면적이 증가되었다(각 p<0.01). 특히 고용량의 PR 투여는 PR의 골다공증 치료효과가 우수함을 증명하였으며(p<0.01), PL과 PF는 효능이 미비하나 PR은 골다공증의 예방 및 치료제로는 상당히 우수한 한약재임이 확인되었다.

• Molecules and Cells
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• 제27권6호
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• pp.673-680
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• 2009

Conversion of the normal soluble form of prion protein, PrP ($PrP^C$), to proteinase K-resistant form ($PrP^{Sc}$) is a common molecular etiology of prion diseases. Proteinase K-resistance is attributed to a drastic conformational change from ${\alpha}$-helix to ${\beta}$-sheet and subsequent fibril formation. Compelling evidence suggests that membranes play a role in the conformational conversion of PrP. However, biophysical mechanisms underlying the conformational changes of PrP and membrane binding are still elusive. Recently, we demonstrated that the putative transmembrane domain (TMD; residues 111-135) of Syrian hamster PrP penetrates into the membrane upon the reduction of the conserved disulfide bond of PrP. To understand the mechanism underlying the membrane insertion of the TMD, here we explored changes in conformation and membrane binding abilities of PrP using wild type and cysteine-free mutant. We show that the reduction of the disulfide bond of PrP removes motional restriction of the TMD, which might, in turn, expose the TMD into solvent. The released TMD then penetrates into the membrane. We suggest that the disulfide bond regulates the membrane binding mode of PrP by controlling the motional freedom of the TMD.

• Biomolecules & Therapeutics
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• 제26권3호
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• pp.313-321
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• 2018

Anti-cancer drug resistance is a major problem in colorectal cancer (CRC) research. Although several studies have revealed the mechanism of cancer drug resistance, molecular targets for chemotherapeutic combinations remain elusive. To address this issue, we focused on the expression of cellular prion protein ($PrP^C$) in 5-FU-resistant CRC cells. In 5-FU-resistant CRC cells, $PrP^C$ expression is significantly increased, compared with that in normal CRC cells. In the presence of 5-FU, $PrP^C$ increased CRC cell survival and proliferation by maintaining the activation of the PI3K-Akt signaling pathway and the expression of cell cycle-associated proteins, including cyclin E, CDK2, cyclin D1, and CDK4. In addition, $PrP^C$ inhibited the activation of the stress-associated proteins p38, JNK, and p53. Moreover, after treatment of 5-FU-resistant CRC cells with 5-FU, silencing of $PrP^C$ triggered apoptosis via the activation of caspase-3. These results indicate that $PrP^C$ plays a key role in CRC drug resistance. The novel strategy of combining chemotherapy with $PrP^C$ targeting may yield efficacious treatments of colorectal cancer.

• BMB Reports
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• 제56권12호
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• pp.645-650
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• 2023

Numerous studies have investigated the cellular prion protein (PrP^C) since its discovery. These investigations have explained that its structure is predominantly composed of alpha helices and short beta sheet segments, and when its abnormal scrapie isoform (PrPSc) is infected, PrPSc transforms the PrP^C, leading to prion diseases, including Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cattle. Given its ubiquitous distribution across a variety of cellular types, the PrP^C manifests a diverse range of biological functions, including cell-cell adhesion, neuroprotection, signalings, and oxidative stress response. PrP^C is also expressed in immune tissues, and its functions in these tissues include the activation of immune cells and the formation of secondary lymphoid tissues, such as the spleen and lymph nodes. Moreover, high expression of PrP^C in immune cells plays a crucial role in the pathogenesis of prion diseases. In addition, it affects inflammation and the development and progression of cancer via various mechanisms. In this review, we discuss the studies on the role of PrP^C from various immunological perspectives.

• IMMUNE NETWORK
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• 제13권4호
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• pp.148-156
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• 2013

The $PrP^C$ is expressed in many types of immune cells including monocytes and macrophages, however, its function in immune regulation remains to be elucidated. In the present study, we examined a role for $PrP^C$ in regulation of monocyte function. Specifically, the effect of a soluble form of $PrP^C$ was studied in human monocytes. A recombinant fusion protein of soluble human $PrP^C$ fused with the Fc portion of human IgG1 (designated as soluble $PrP^C$-Fc) bound to the cell surface of monocytes, induced differentiation to macrophage-like cells, and enhanced adherence and phagocytic activity. In addition, soluble $PrP^C$-Fc stimulated monocytes to produce pro-inflammatory cytokines such as $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6. Both ERK and $NF-{\kappa}B$ signaling pathways were activated in soluble $PrP^C$-treated monocytes, and inhibitors of either pathway abrogated monocyte adherence and cytokine production. Taken together, we conclude that soluble $PrP^C$-Fc enhanced adherence, phagocytosis, and cytokine production of monocytes via activation of the ERK and $NF-{\kappa}B$ signaling pathways.