• BMB Reports
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• 제49권10호
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• pp.542-547
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• 2016

Acid-sensing ion channels (ASICs) are proton-gated cation channels widely expressed in the nervous system. Proton sensing by ASICs has been known to mediate pain, mechanosensation, taste transduction, learning and memory, and fear. In this study, we investigated the differential subcellular localization of ASIC2a and ASIC3 in heterologous expression systems. While ASIC2a targeted the cell surface itself, ASIC3 was mostly accumulated in the ER with partial expression in the plasma membrane. However, when ASIC3 was co-expressed with ASIC2a, its surface expression was markedly increased. By using bimolecular fluorescence complementation (BiFC) assay, we confirmed the heteromeric association between ASIC2a and ASIC3 subunits. In addition, we observed that the ASIC2a-dependent surface trafficking of ASIC3 remarkably enhanced the sustained component of the currents. Our study demonstrates that ASIC2a can increase the membrane conductance sensitivity to protons by facilitating the surface expression of ASIC3 through herteromeric assembly.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.379-382
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• 2018

Newcastle disease virus (NDV) 감염된 baby hamster kidney 세포에서 Syncytium (합포체) 형성은 세포막 표면으로의 수송된 바이러스 당단백질 hemagglutinin-neuramidase에 의해 일어난다. HAU 값은 추출물의 농도가 25과 $3.2{\mu}g/mL$ 사이에서는 현저하게 감소하였으나, $25{\mu}g/mL$ 농도에서는 NDV 감염된 HAD (%)는 광범위한 흡착능의 감소를 나타났으나 바이러스 당단백질의 세포내 생합성은 저해되지 않았다. 그러므로 오배자 추출물은 바이러스 당단백질의 세포막으로의 수송과 함께 합포체 형성을 저해하여 항바이러스 활성을 갖는 것으로 결론된다. 또한 오배자 추출물의 저해활성을 조사한 결과 ${\alpha}-glucosidase$에 대한 추출물의 $IC_{50}$은 $12.5{\mu}g/mL$이었으며, ${\beta}-glucosidase$, ${\alpha}-glucosidase$, ${\beta}-mannosidase$에 대한 오배자 추출물의 $IC_{50}$은 각각 26, 36, $50{\mu}g/mL$로 나타나 ${\beta}-type$ glycosidases 보다 ${\alpha}-type$ glycosidase에 대한 효소활성 저해능이 우수하였다. 따라서 $IC_{50}$ 농도에서는 세포내에서 당단백질 생합성은 저해되지 않으며 당단백질의 수송을 저해하는 것으로 판단되었으며 향후 항바이러스 관련 작용기작의 연구가 필요하다고 사료된다.

• The Korean Journal of Physiology and Pharmacology
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• 제28권5호
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• pp.435-447
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• 2024

Secretory proteins, including plasma membrane proteins, are generally known to be transported to the plasma membrane through the endoplasmic reticulum-to-Golgi pathway. However, recent studies have revealed that several plasma membrane proteins and cytosolic proteins lacking a signal peptide are released via an unconventional protein secretion (UcPS) route, bypassing the Golgi during their journey to the cell surface. For instance, transmembrane proteins such as the misfolded cystic fibrosis transmembrane conductance regulator (CFTR) protein and the Spike protein of coronaviruses have been observed to reach the cell surface through a UcPS pathway under cell stress conditions. Nevertheless, the precise mechanisms of the UcPS pathway, particularly the molecular machineries involving cytosolic motor proteins, remain largely unknown. In this study, we identified specific kinesins, namely KIF1A and KIF5A, along with cytoplasmic dynein, as critical players in the unconventional trafficking of CFTR and the SARS-CoV-2 Spike protein. Gene silencing results demonstrated that knockdown of KIF1A, KIF5A, and the KIF-associated adaptor protein SKIP, FYCO1 significantly reduced the UcPS of △F508-CFTR. Moreover, gene silencing of these motor proteins impeded the UcPS of the SARS-CoV-2 Spike protein. However, the same gene silencing did not affect the conventional Golgi-mediated cell surface trafficking of wild-type CFTR and Spike protein. These findings suggest that specific motor proteins, distinct from those involved in conventional trafficking, are implicated in the stress-induced UcPS of transmembrane proteins.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.81-81
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• 2017

Nanotechnology is of great importance to molecular biology and medicine because life processes are maintained by the action of a series of molecular nanomachines in the cell machinery. Recent advances in nanoscale materials that possess emergent physical properties and molecular organization hold great promise to impact human health in the diagnostic and therapeutic arenas. In order to be effective, nanomaterials need to navigate the host biology and traffic to relevant biological structures, such as diseased or pathogenic cells. Moreover, nanoparticles intended for human administration must be designed to interact with, and ideally leverage, a living host environment. Inspired by nature, we use peptides to transfer biological trafficking properties to synthetic nanoparticles to achieve targeted delivery of payloads. In this talk, development of nanoscale materials will be presented with a particular focus on applications to three outstanding health problems: bacterial infection, cancer detection, and traumatic brain injury. A biodegradable nanoparticle carrying a peptide toxin trafficked to the bacterial surface has antimicrobial activity in a pneumonia model. Trafficking of a tumor-homing nanoprobes sensitively detects cancer via a high-contrast time-gated imaging system. A neuron-targeted nanoparticle carrying siRNA traffics to neuronal populations and silences genes in a model of traumatic brain injury. Unique combinations of material properties that can be achieved with nanomaterials provide new opportunities in translational nanomedicine. This framework for constructing nanomaterials that leverage bio-inspired molecules to traffic diagnostic and therapeutic payloads can contribute on better understanding of living systems to solve problems in human health.

• 한국식품저장유통학회지
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• 제21권5호
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• pp.735-739
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• 2014

Newcastle disease virus(NDV) 감염된 baby hamster kidney(BHK) 세포에서 syncytium(합포체) 형성은 세포막 표면으로의 수송된 바이러스 당단백질 hemagglutinin-neuramidase(HN)에 의해 일어난다. HAU 값은 추출물의 농도가 25과 3.2 ug/mL 사이에서는 현저하게 감소하였으나, NDV 감염된 HAD(%)는 25 ug/mL 농도에서 광범위한 흡착능의 감소를 나타내 바이러스 당단백질의 세포내 생합성은 저해되지 않았다. 그러므로, 약용식물인 마황 메탄올 추출물이 바이러스 당단백질의 세포막으로의 수송과 함께 합포체 형성을 저해하여 항바이러스 작용을 하였다. 또한 마황 추출물의 저해활성을 조사한 결과 ${\alpha}$-glucosidase에 대한 추출물의 $IC_{50}$은 $18{\mu}g/mL$이었으며, ${\beta}$-glucosidase, ${\alpha}$-mannosidase, ${\beta}$-mannosidase에 대한 마황 추출물의 $IC_{50}$은 각각 60, 40, $150{\mu}g/mL$로 나타나 ${\beta}$-type glycosidases 보다 ${\alpha}$-type glycosidase에 대한 효소활성 저해능이 우수하였다. 따라서 $IC_{50}$농도에서는 세포내에서 당단백질 생합성은 저해되지 않으며 당단백질의 수송을 저해하는 것으로 판단되었으며 향후 항바이러스 관련 작용기작의 연구가 필요하다고 판단된다.

• Molecules and Cells
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• 제44권10호
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• pp.758-769
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• 2021

Calcium homeostasis modulator 1 (CALHM1) is a membrane protein with four transmembrane helices that form an octameric ion channel with voltage-dependent activation. There are four conserved cysteine (Cys) residues in the extracellular domain that form two intramolecular disulfide bonds. We investigated the roles of C42-C127 and C44-C161 in human CALHM1 channel biogenesis and the ionic current (I_CALHM1). Replacing Cys with Ser or Ala abolished the membrane trafficking as well as I_CALHM1. Immunoblotting analysis revealed dithiothreitol-sensitive multimeric CALHM1, which was markedly reduced in C44S and C161S, but preserved in C42S and C127S. The mixed expression of C42S and wild-type did not show a dominant-negative effect. While the heteromeric assembly of CALHM1 and CALHM3 formed active ion channels, the co-expression of C42S and CALHM3 did not produce functional channels. Despite the critical structural role of the extracellular cysteine residues, a treatment with the membrane-impermeable reducing agent tris(2-carboxyethyl) phosphine (TCEP, 2 mM) did not affect I_CALHM1 for up to 30 min. Interestingly, incubation with TCEP (2 mM) for 2-6 h reduced both I_CALHM1 and the surface expression of CALHM1 in a time-dependent manner. We propose that the intramolecular disulfide bonds are essential for folding, oligomerization, trafficking and maintenance of CALHM1 in the plasma membrane, but dispensable for the voltage-dependent activation once expressed on the plasma membrane.

• Molecules and Cells
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• 제39권10호
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• pp.762-767
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• 2016

Fasciclin II (FasII), the Drosophila ortholog of neural cell adhesion molecule (NCAM), plays a critical role in synaptic stabilization and plasticity. Although this molecule undergoes constitutive cycling at the synaptic membrane, how its membrane trafficking is regulated to ensure proper synaptic development remains poorly understood. In a genetic screen, we recovered a mutation in Drosophila mical-like that displays an increase in bouton numbers and a decrease in FasII levels at the neuromuscular junction (NMJ). Similar phenotypes were induced by presynaptic, but not postsynaptic, knockdown of mical-like expression. FasII trafficking assays revealed that the recycling of internalized FasII molecules to the cell surface was significantly impaired in mical-like-knockdown cells. Importantly, this defect correlated with an enhancement of endosomal sorting of FasII to the lysosomal degradation pathway. Similarly, synaptic vesicle exocytosis was also impaired in mical-like mutants. Together, our results identify Mical-like as a novel regulator of synaptic growth and FasII endocytic recycling.

• Journal of Microbiology and Biotechnology
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• 제21권3호
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• pp.263-266
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• 2011

Methylelaiophylin isolated from Streptomyces melanosporofaciens was selected as an ${\alpha}$-glucosidase inhibitor with an $IC_{50}$ value of 10 ${\mu}M$. It showed mixed-type inhibition of ${\alpha}$-glucosidase with a $K_i$ value of 5.94 ${\mu}M$. In addition, methylelaiophylin inhibited the intracellular trafficking of hemagglutinin-neuramidase (HN), a glycoprotein of Newcastle disease virus (NDV), in baby hamster kidney (BHK) cells. Methylelaiophylin inhibited the cell surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• Molecules and Cells
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• 제41권7호
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• pp.676-683
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• 2018

Cilia are highly specialized antennae-like organelles that extend from the cell surface and act as cell signaling hubs. Intraflagellar transport (IFT) is a specialized form of intracellular protein trafficking that is required for the assembly and maintenance of cilia. Because cilia are so important, mutations in several IFT components lead to human disease. Thus, clarifying the molecular functions of the IFT proteins is a high priority in cilia biology. Live imaging in various species and cellular preparations has proven to be an important technique in both the discovery of IFT and the mechanisms by which it functions. Live imaging of Drosophila cilia, however, has not yet been reported. Here, we have visualized the movement of IFT in Drosophila cilia using time-lapse live imaging for the first time. We found that NOMPB-GFP (IFT88) moves according to distinct parameters depending on the ciliary segment. NOMPB-GFP moves at a similar speed in proximal and distal cilia toward the tip (${\sim}0.45{\mu}m/s$). As it returns to the ciliary base, however, NOMPB-GFP moves at ${\sim}0.12{\mu}m/s$ in distal cilia, accelerating to ${\sim}0.70{\mu}m/s$ in proximal cilia. Furthermore, while live imaging NOMPB-GFP, we observed one of the IFT proteins required for retrograde movement, Oseg4 (WDR35), is also required for anterograde movement in distal cilia. We anticipate our time-lapse live imaging analysis technique in Drosophila cilia will be a good starting point for a more sophisticated analysis of IFT and its molecular mechanisms.

• 한국식품과학회지
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• 제46권2호
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• pp.245-248
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• 2014

Newcastle disease virus (NDV) 감염된 baby hamster kidney (BHK) 세포에서 합포체 형성은 세포막 표면으로의 수송된 바이러스 당단백질 hemagglutinin-neuramidase (HN)에 의해 일어난다. HAU 값은 추출물의 농도가 25.0과 $3.2{\mu}g/mL$ 사이에서는 현저하게 감소하였으나, NDV 감염된 HAD (%)는 $25.0{\mu}g/mL$ 농도에서 광범위한 흡착능의 감소를 나타내 바이러스 당단백질의 세포내 생합성은 저해되지 않았다. 그러므로, 약용식물인 빈랑 메탄올 추출물이 바이러스 당단백질의 세포막으로의 수송과 함께 합포체 형성을 저해하여 항바이러스 작용을 하였다. 또한 빈랑 추출물의 저해활성을 조사한 결과 ${\alpha}$-glucosidase에 대한 추출물의 $IC_{50}$은 $10.0{\mu}g/mL$이었으며, ${\alpha}$-mannosidase, ${\beta}$-glucosidase, ${\beta}$-mannosidase에 대한 빈랑 추출물의 $IC_{50}$은 각각 20.0, 40.0, $80.0{\mu}g/mL$로 나타나 ${\beta}$-type glycosidases 보다 ${\alpha}$-type glycosidases에 대한 효소활성 저해능이 우수하였다. 따라서 $IC_{50}$농도에서는 세포내에서 당단백질 생합성은 저해되지 않으며 당단백질의 수송을 저해하는 것으로 판단되었으며 향후 항바이러스 관련 작용기작의 연구가 필요하다고 판단된다.