• 생명과학회지
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• 제23권9호
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• pp.1163-1169
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• 2013

인슐린은 근육세포 표면으로 포도당 수송체 4(glucose transporter 4, GLUT4)를 유도하여 혈액 속의 포도당을 세포 내로 유입시키도록 작용한다고 알려져 있다. Fagopyritol은 인슐린과 유사한 작용을 하는 것으로 알려져 있으므로, 본 연구에서는 혈당강하 효과가 있다고 알려진 fagopyritol을 랫드의 근육세포주(L6GLUT4myc 세포)에 처리하여, 아직 명확하게 밝혀지지 않은 fagopyritol의 혈당강하 기전을 규명하고자 수행하였다. Fagopyritol의 혈당강하 기전을 규명하기 위하여 근원세포(myoblast)와 근관세포(myotube)에 fagopyritol을 처리하여 액틴 필라멘트의 구조와 GLUT4에 미치는 영향을 분석하였다. Fagopyritol을 myoblast에 처리하였을 때, GLUT4가 처리군에서 대조군과 비교하여 유의 있게 원형질막 쪽으로 유도되는 것을 확인하였고, 액틴 필라멘트의 구조가 재조정되면서 GLUT4의 이동을 돕는 것으로 생각된다. 또한 fagopyritol이 인슐린과 유사한 작용 경로를 가지는지 확인하기 위하여, 인슐린 작용 경로에서 중요한 역할을 하는 것으로 알려진 phosphatidylinositol 3-kinase (PI3K)의 억제제인 LY294002를 fagopyritol과 함께 처리하였을 때 GLUT4가 원형질막 쪽으로 유도되지 않는 것을 확인하였다. Fagopyritol을 myotube에 처리하였을 때, myoblast에 처리하였을 때와 유사한 결과를 나타내었다. 이러한 결과를 종합하면 fagopyritol이 인슐린과 유사한 작용을 하여 액틴 필라멘트의 구조 변경과 GLUT4의 이동을 촉진시키는 것으로 사료된다.

• 생명과학회지
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• 제17권2호통권82호
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• pp.204-210
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• 2007

평활근 ${\alpha}$-트로포마이오신의 높은 액틴 친화력은 아미노산 잔기 Gln276 및 Thr277에 기인한다는 이전 보고에 따라, 2 잔기 중 어느 잔기가 액틴 친화력에 더 중요한 가를 알아보기 위하여 골격근 트로포마이오신의 His 혹은 Ala 단일 잔기를 각각 Gln 혹은 Thr으로 치환한 돌연변이 트로포마이오신을 제작하여 대장균에서 대량발현 시킨 후 정제하여 액틴 결합력을 측정하였다. 비록 비아세틸화된 트로포마이오신의 경우 Gln 및 Thr 잔기가 최고 액틴친화력을 위해 모두 필요하나, 돌연변이 트로포마이신 중 Gln 잔기를 가진 돌연변이 트로포마이오신들이 다른 돌연변이 트로포마이오신들에 비하여 3에서 4배 높은 액틴친화력을 보였다. 이러한 결과는 평활근 ${\alpha}$-트로포마이오신의 높은 액틴 친화력은 Thr277 잔기보다 Gln276 잔기에 주로 기인한다는 것을 의미한다.

• Animal cells and systems
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• 제1권1호
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• pp.93-98
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• 1997

The present study investigated the cellular localization of a-subunit of Gq (Gaq) protein in developing L8E63, rat skeletal muscle cell line. The colocalization of Gaq with actin cytoskeleton was demonstrated by double-labeling experiments. In mononucleated myoblasts, the immuno-fluorescence staining pattern of Gaq was almost identical with that of F-actin visualized with rhodamine-conjugated phalloidin. However, this colocalization of Gaq with cytoskeleton was not maintained in multinucleated myotubes. The staining pattern of Gaq in myotubes did not match with any specific subcellular structure, but appeared as a uniformly distributed diffuse staining throughout the whole cell surface. Interestingly, change in the expression level of Gaq was not detected during myoblast differentiation, suggesting that actin-associated Gaq protein might dissociate from the cytoskeleton as cells differentiate. Immunocytochemical experiments using specific antibodies directed against several G proteins indicated that the subcellular localizations of Gai1, Gai2, Gai3, and Gao were different from those obtained with Gaq.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3213-3222
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• 2015

Background: Cancer metastasis depends on cell motility which is driven by cycles of actin polymerization and depolymerization. Reactive oxygen species (ROS) and metabolic oxidative stress have long been associated with cancer. ROS play a vital role in regulating actin dynamics that are sensitive to oxidative modification. The current work aimed at studying the effects of sub-lethal metabolic oxidative stress on actin cytoskeleton, focal adhesion and cell migration. Materials and Methods: T47D human breast cancer cells were treated with 2-deoxy-D-glucose (2DG), L-buthionine sulfoximine (BSO), or doxorubicin (DOX), individually or in combination, and changes in intracellular total glutathione and malondialdehyde (MDA) levels were measured. The expression of three major antioxidant enzymes was studied by immunoblotting, and cells were stained with fluorescent-phalloidin to evaluate changes in F-actin organization. In addition, cell adhesion and degradation ability were measured. Cell migration was studied using wound healing and transwell migration assays. Results: Our results show that treating T47D human breast cancer cells with drug combinations (2DG/BSO, 2DG/DOX, or BSO/DOX) decreased intracellular total glutathione and increased oxidized glutathione, lipid peroxidation, and cytotoxicity. In addition, the drug combinations caused a reduction in cell area and mitotic index, prophase arrest and a decreased ability to form invadopodia. The formation of F-actin aggregates was increased in treated T47D cells. Moreover, combination therapy reduced cell adhesion and the rate of cell migration. Conclusions: Our results suggest that exposure of T47D breast cancer cells to combination therapy reduces cell migration via effects on metabolic oxidative stress.

• Asian Pacific Journal of Cancer Prevention
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• 제16권6호
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• pp.2187-2191
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• 2015

Background: Protrusive structures formed by migrating and invading cells are termed lamellipodia, filopodia, invadopodia and podosomes. Lamellipodia and filopodia appear on the leading edges of migrating cells and function to command the direction of the migrating cells. Invadopodia and podosomes are special F-actin-rich matrix-degrading structures that arise on the ventral surface of the cell membrane. Invadopodia are found in a variety of carcinomatous cells including squamous cell carcinoma of head and neck region whereas podosomes are found in normal highly motile cells of mesenchymal and myelomonocytic lineage. Invadopodia-associated protein markers consisted of 129 proteins belonging to different functional classes including WASP, NWASP, cortactin, Src kinase, Arp 2/3 complex, MT1-MMP and F-actin. To date, our current understanding on the role(s) of these regulators of actin dynamics in tumors of the orofacial region indicates that upregulation of these proteins promotes invasion and metastasis in oral squamous cell carcinoma, is associated with poor/worst prognostic outcome in laryngeal cancers, contributes to the persistent growth and metastasis characteristics of salivary gland adenoid cystic carcinoma, is a significant predictor of increased cancer risk in oral mucosal premalignant lesions and enhances local invasiveness in jawbone ameloblastomas.

• BMB Reports
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• 제55권2호
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• pp.104-109
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• 2022

Skeletal myogenesis is essential to keep muscle mass and integrity, and impaired myogenesis is closely related to the etiology of muscle wasting. Recently, miR-141-3p has been shown to be induced under various conditions associated with muscle wasting, such as aging, oxidative stress, and mitochondrial dysfunction. However, the functional significance and mechanism of miR-141-3p in myogenic differentiation have not been explored to date. In this study, we investigated the roles of miR-141-3p on CFL2 expression, proliferation, and myogenic differentiation in C2C12 myoblasts. MiR-141-3p appeared to target the 3'UTR of CFL2 directly and suppressed the expression of CFL2, an essential factor for actin filament (F-actin) dynamics. Transfection of miR-141-3p mimic in myoblasts increased F-actin formation and augmented nuclear Yes-associated protein (YAP), a key component of mechanotransduction. Furthermore, miR-141-3p mimic increased myoblast proliferation and promoted cell cycle progression throughout the S and G2/M phases. Consequently, miR-141-3p mimic led to significant suppressions of myogenic factors expression, such as MyoD, MyoG, and MyHC, and hindered the myogenic differentiation of myoblasts. Thus, this study reveals the crucial role of miR-141-3p in myogenic differentiation via CFL2-YAP-mediated mechanotransduction and provides implications of miRNA-mediated myogenic regulation in skeletal muscle homeostasis.

• Journal of Ginseng Research
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• 제38권4호
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• pp.233-238
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• 2014

Background: The actin cytoskeleton in podocytes is essential for the maintenance of its normal structure and function. Its disruption is a feature of podocyte foot-process effacement and is associated with proteinuria. ${\alpha}$-Actinin-4 in podocytes serves as a linker protein binding the actin filaments of the cytoskeleton. Methods: To investigate the effect of ginseng total saponin (GTS) on the pathological changes of podocyte ${\alpha}$-actinin-4 induced by diabetic conditions, we cultured mouse podocytes under normal glucose (5mM) or high glucose (HG, 30mM) conditions, with or without the addition of advanced glycosylation end products (AGE), and treated with GTS. Results: In confocal imaging, ${\alpha}$-actinin-4 colocalized with the ends of F-actin fibers in cytoplasm, but diabetic conditions disrupted F-actin fibers and concentrated ${\alpha}$-actinin-4 molecules at the peripheral cytoplasm. GTS upregulated ${\alpha}$-actinin protein in a time- and dose-dependent manner, and suppressed the receptor for AGE levels in western blotting. Diabetic conditions, including HG, AGE, and both together, decreased cellular ${\alpha}$-actinin-4 protein levels at 24 h and 48 h. Such quantitative and qualitative changes of ${\alpha}$-actinin-4 protein induced by diabetic conditions were mitigated by GTS. Conclusion: These findings imply that both HG and AGE have an influence on the distribution and amount of ${\alpha}$-actinin-4 in podocytes that can be recovered by GTS.

• BMB Reports
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• 제48권10호
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• pp.583-588
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• 2015

Microtubule actin crosslinking factor 1 (MACF1), a widely expressed cytoskeletal linker, plays important roles in various cells by regulating cytoskeleton dynamics. However, its role in osteoblastic cells is not well understood. Based on our previous findings that the association of MACF1 with F-actin and microtubules in osteoblast-like cells was altered under magnetic force conditions, here, by adopting a stable MACF1-knockdown MC3T3-E1 osteoblastic cell line, we found that MACF1 knockdown induced large cells with a binuclear/multinuclear structure. Further, immunofluorescence staining showed disorganization of F-actin and microtubules in MACF1-knockdown cells. Cell counting revealed significant decrease of cell proliferation and cell cycle analysis showed an S phase cell cycle arrest in MACF1-knockdown cells. Moreover and interestingly, MACF1 knockdown showed a potential effect on cellular MTT reduction activity and mitochondrial content, suggesting an impact on cellular metabolic activity. These results together indicate an important role of MACF1 in regulating osteoblastic cell morphology and function.

• Journal of Microbiology and Biotechnology
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• 제10권5호
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• pp.606-611
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• 2000

Dimorphic yeast Candida albicans reversibly switches between the form of yeast and hyphae depending on external conditions. We investigated possible roles of the myosin family in the growth and dimorphic switches of C. albicans with a general myosin ATPase inhibitor, 2,3-butanedione-2-monoxime (BDM). Transition to hyphae as well as proliferation by budding was completely inhibited by BDM at 16 mM. Presence of 16 mM BDM did not affect hyphae-to-bud transition but it blocked budding. The effects of BDM on yeast growth and dimorphic switches were reversible. More than 70% of the BDM-treated cells demonstrated defects in the amount and the polarized localization of F-actin as well as in the shape and migration of the nucleus, suggesting that myosin activities are needed in these cellular processes of C. albicans.

• 한국동물학회:뉴스레터
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• 제12권2호
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• pp.109.2-109
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• 1995

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