• 한국자기공명학회논문지
• /
• 제11권2호
• /
• pp.85-94
• /
• 2007

Vanilloid receptor I [transient receptor potential vanilloid subfamily member 1 (TRPV1), also known as VR1] is a non-selective cationic channel activated by noxious heat, vanilloids, and acid, thereby causing pain. VR1 possesses six transmembrane domain and N-and C-terminus cytosolic domains, and appears to be a homotetramer. We studied the structural properties of Cterminus of VR1 (VR1C) using CD and NMR spectroscopy. DPC micelles, with a zwitterionic surface, and SDS micelles, with a negatively charged surface, were used as a membrane mimetic model system. Both SDS and DPC micelles could increase the stability of helical structures and/or reduce the aggregation form of the VR1C. However, the structural changing mode of the VR1C induced by the SDS and DPC micelles was different. The changes according to the various pHs were also different in two micelles conditions. Because the net charges of the SDS and DPC micelles are negative and neutral, respectively, we anticipate that this difference might affect the structure of the VR1C by electrostatic interaction between the surface of the VR1C and phospholipids of the detergent micelles. Based on these similarity and dissimilarity of changing aspects of the VR1C, it is supposed that the VR1C probably has the real pI value near the pH 7. Generally, mild extracellular acidic pH ($6.5{\sim}6.8$) potentiates VRI channel activation by noxious heat and vanilloids, whereas acidic conditions directly activate the channel. The channel activation of the VRI might be related to the structural change of VR1C caused by pH (electrostatic interactions), especially near the pH 7. By measuring the $^1-^{15}N$ TROSY spectra of the VR1C, we could get more resolved and dispersed spectra at the low pH and/or detergent micelles conditions. We will try to do further NMR experiments in low pH with micelles conditions in order to get more information about the structure of VR1C.

• 대한약리학회지
• /
• 제8권1호
• /
• pp.67-75
• /
• 1972

Many studies on the mechanism of the inotropic action of cardiac glycosides have shown the possible intimate relationship between the mobilization of intracellular calcium and inotropic effect. Evidence obtained from recent studies suggests that cardiac glycosides may increase the intracellular $Ca^{++}$ concentration through the release of this ion from cellular or intracellular membrane. It seemed imperative to study the effect of ouabain on the interaction between mitochondria and $Ca^{++}$, because mitochondria are known to have a rather powerful $Ca^{++}$ pump mechanism which may have an important role on the regulation of intracellular $Ca^{++}$ concentration. The present investigations was made into the effect of ouabain on $Ca^{++}$ untake of mitochondria in the presence of ATP and its dependence on $K^+$ and $Na^+$ in the medium. The results are summarized as follows: 1. The rate of rise in the turbidity of superprecipitation was solely influenced by ionic strength of the medium, not by the species of ion, i.e. $Na^+$ or $K^+$. The higher ionic strength suppressed and the lower enhanced the rate of superprecipitation respectively. 2. No effect of ouabain was found on the rate of superprecipitation. 3. Mitochondria depressed the rate of superpretipitation, and the depressed rate of superprecipitation by mitochondria was reversed by ouabain, and the degree of this reversal was almost identical in $Na^+$ and $K^+$ medium. 4. $Ca^{++}$ uptake of mitochondria was inhibited by ouabain in the presence of ATP and the degree of inhibition showed the dose-response manner in terms of concentration of ouabain. 5. In the absence of ATP, mitochondria took or the $Ca^{++}$ in initial period but released it later. Such uptake and release of $Ca^{++}$ was not influenced by ouabain. 6. It is suggested that intracellular calcium mobilization by ouabain through the action upon the mitochondria was due to inhibition on ATP-dependent $Ca^{++}$ uptake by this agent, not to the action upon so called binding.

• Mycobiology
• /
• 제45권4호
• /
• pp.297-311
• /
• 2017

Saprolegniasis is one of the most devastating oomycete diseases in freshwater fish which is caused by species in the genus Saprolegnia including Saprolegnia parasitica. In this study, we isolated the strain of S. parasitica from diseased rainbow trout in Korea. Morphological and molecular based identification confirmed that isolated oomycete belongs to the member of S. parasitica, supported by its typical features including cotton-like mycelium, zoospores and phylogenetic analysis with internal transcribed spacer region. Pathogenicity of isolated S. parasitica was developed in embryo, juvenile, and adult zebrafish as a disease model. Host-pathogen interaction in adult zebrafish was investigated at transcriptional level. Upon infection with S. parasitica, pathogen/antigen recognition and signaling (TLR2, TLR4b, TLR5b, NOD1, and major histocompatibility complex class I), pro/anti-inflammatory cytokines (interleukin $[IL]-1{\beta}$, tumor necrosis factor ${\alpha}$, IL-6, IL-8, interferon ${\gamma}$, IL-12, and IL-10), matrix metalloproteinase (MMP9 and MMP13), cell surface molecules ($CD8^+$ and $CD4^+$) and antioxidant enzymes (superoxide dismutase, catalase) related genes were differentially modulated at 3- and 12-hr post infection. As an anti-Saprolegnia agent, plant based lawsone was applied to investigate on the susceptibility of S. parasitica showing the minimum inhibitory concentration and percentage inhibition of radial growth as $200{\mu}g/mL$ and 31.8%, respectively. Moreover, natural lawsone changed the membrane permeability of S. parasitica mycelium and caused irreversible damage and disintegration to the cellular membranes of S. parasitica. Transcriptional responses of the genes of S. parasitica mycelium exposed to lawsone were altered, indicating that lawsone could be a potential anti-S. parasitica agent for controlling S. parasitica infection.

• 생명과학회지
• /
• 제31권9호
• /
• pp.856-861
• /
• 2021

CD82/KAI1은 분자촉진제로서 암 전이억제자로 역할이 잘 알려져 있으나, 최근 줄기 전구 세포와 혈관 신생, 근육에서 다양한 역할들이 밝혀지고 있다. 이에 본 연구진은 최근에 보고된 CD82의 다양한 기능과 역할에 관하여 총설 하고자 한다. CD82는 4개의 막 통과 도메인을 가진 테트라스파닌의 한 종류로 암의 전이 과정에 관여하는 세포접착분자들과의 상호작용을 통하여 암세포의 이동 능력을 저해한다. 암 전이 억제자로의 기능 외에도 줄기세포 니쉬에서도 그 역할이 밝혀졌다. 골수에서 분화재생능력이 뛰어난 최상위 조혈모세포(LT-HSC)에서 CD82가 발현되며, DARC와의 상호결합으로 줄기세포의 휴면을 유도한다. 줄기세포의 휴면 조절 외에도, CD82는 Rac1 활성 조절을 통해 조혈모세포의 골수로의 귀환 및 생착에도 역할을 한다. 또한, CD82는 근육 줄기 세포의 분화능을 유지시키며, 혈관 내피세포에서 세포 접착 분자와 IL-6, VEGF와 같은 사이토카인의 발현을 저해하여 혈관 신생을 억제한다. CD82는 다양한 조직 및 줄기-전구 세포에서 계급을 구별할 수 있는 핵심 세포막 표면 단백질이며, 세포 자원의 증폭 및 검증에 있어 중요하다. 다양한 기관과 세포에서 CD82의 역할과 추가적인 연구들이 줄기세포치료의 임상적 적용에 있어 큰 도움이 되기를 기대한다.

• 동의생리병리학회지
• /
• 제17권1호
• /
• pp.77-84
• /
• 2003

Cancer, which is expressed in various forms, is one of the leading causes of human death, Soamsan (SAS) is composed of ten medicinal herb, the prescription was made according to the principles of Oriental traditional medicine based on the concept of synergic effects and interaction of among the components. SAS has been used for the cancer therapy, but the mechanism of it's effect is not well known. In the present study, the cytotoxic effect of the SAS water extract on cancer cell lines was investigated by the method of MTT in A549 cell lines and the anti-angiogenic effect was shown in the assay of chorioallantoic membrane (CAM) and in the cornea of rat administerd orally with SAS water extraction. The viability of A549 cell lines was not affected by the whole extract of SAS but the n-Hexan fraction of SAS water extract showed strong cytotoxicity which was not seemed to be done by the apoptotic mechanism. SAS water extract showed inhibition effects of angiogenesis induced in the cornea of rat and CAM assay. As the above results, it is suggested that SAS can be a candidate for new prescription for cancer therapy.

• 한국응용곤충학회지
• /
• 제22권2호
• /
• pp.147-159
• /
• 1983

In general, herbicides have been classified according to selectivity, mobility. time of application, methods of application, mode of action and chemical property and structure. However, there was no generally accepted classification system for practical use in the field. The primary processes affected by the majority of herbicides are the growth process through cell elongation and/or cell division, the photosynthetic process specifically the light reaction, the oxidative phosphorylation and the integrity of the membrane systems. The usual approach in the study of the mechanism by which herbicides kill or inhibit the growth of plants is to initially determine the morphological phototoxicity systems, The mechanism by which a herbicide kills a plant or suppresses its development is actually the resultant effect of primary and secondary(or side) effects. In most instances, the death of the plant is due to the secondary effects. To induce the desired response, a herbicide must be able to gain entry into the plants and once inside, to be transported within the plant to its site(s) of activity in concentrations great enough. Obstacles to the entry and movement of herbicides in plants are generally classified by leaf and soil obstacles, translocation obstacles and biochemical obstacles, and these obstacles are also strongly influenced by plant species and by environmental factors such as light, temperature, rainfall and relative humidity. And hence, in most instances, results obtained from laboratory or greenhous vary from those of field experiment. Author attempted to classify herbicides from the field experiment using the two-dimensional ordination analysis to obtain practical information for selecting effective herbicides or to choose effective herbicide combinations for increasing herbicidal efficacy or reducing the chemical cost. Based on this two-dimensional diagram, desired herbicides or combinations were selected and further investigated for the interaction effects whether these combinations are synergistic, additive or antagonistic. From the results, it was concluded that these new approach could possibly be give more comprehensive informations about effective use of herbicide than any other systems.

• Molecules and Cells
• /
• 제27권1호
• /
• pp.39-45
• /
• 2009

Ligand-dependent or independent oligomerization of receptor protein tyrosine kinase (RPTK) is often an essential step for receptor activation and intracellular signaling. The novel oncogene with kinase-domain (NOK) is a unique RPTK that almost completely lacks an ectodomain, expresses intracellularly and activates constitutively. However, it is unknown whether NOK can form oligomer or what function oligomerization would have. In this study, two NOK deletion mutants were generated by either removing the ectodomain ($NOK{\Delta}ECD$) or including the endodomain (NOK-ICD). Co-immunoprecipitation demonstrated that the transmembrane (TM) domain of NOK was essential for its intermolecular interaction. The results further showed that NOK aggregated more closely as lower order oligomers (the dimer- and trimer-sized) than either deletion mutant did since NOK could be crosslinked by both Sulfo-EGS and formaldehyde, whereas either deletion mutant was only sensitive to Sulfo-EGS. Removing the NOK TM domain (NOK-ICD) not only markedly promoted higher order oligomerization, but also altered the subcellular localization of NOK and dramatically elevated the NOK-mediated constitutive activation of extracellular signal-regulated kinase (ERK). Moreover, NOK-ICD but not NOK or $NOK{\Delta}ECD$ was co-localized with the upstream signaling molecule RAS on cell membrane. Thus, TM-mediated intermolecular contacting may be mainly responsible for the constitutive activation of NOK and contribute to the autoinhibitory effect on RAS/MAPK signaling.

• Molecules and Cells
• /
• 제41권4호
• /
• pp.320-330
• /
• 2018

${\delta}$-Catenin, a member of the p120-catenin subfamily of armadillo proteins, reportedly increases during the late stage of prostate cancer. Our previous study demonstrates that ${\delta}$-catenin increases the stability of EGFR in prostate cancer cell lines. However, the molecular mechanism behind ${\delta}$-catenin-mediated enhanced stability of EGFR was not explored. In this study, we hypothesized that ${\delta}$-catenin enhances the protein stability of EGFR by inhibiting its lysosomal degradation that is mediated by c-casitas b-lineage lymphoma (c-Cbl), a RING domain E3 ligase. c-Cbl monoubiquitinates EGFR and thus facilitates its internalization, followed by lysosomal degradation. We observed that ${\delta}$-catenin plays a key role in EGFR stability and downstream signaling. ${\delta}$-Catenin competes with c-Cbl for EGFR binding, which results in a reduction of binding between c-Cbl and EGFR and thus decreases the ubiquitination of EGFR. This in turn increases the expression of membrane bound EGFR and enhances EGFR/Erk1/2 signaling. Our findings add a new perspective on the role of ${\delta}$-catenin in enhancing EGFR/Erk1/2 signaling-mediated prostate cancer.

• Biomolecules & Therapeutics
• /
• 제17권3호
• /
• pp.288-292
• /
• 2009

Interactions between tumor cells and the extracellular matrix (ECM) strongly influence tumor development, affecting cell survival, proliferation and migration. Fibronectin, a major component of ECM, has been shown to interact with integrins especially the ${\alpha}5{\beta}1$ integrin. Cell invasion and metastasis are often associated with matrix metalloproteinases (MMPs) which are capable of digesting the different components of the ECM and basement membrane. MMP-2 is produced as a latent pro-MMP-2 (72 kDa) to be activated, resulting the 62 kDa active MMP-2. In this study, we investigated the effect of fibronectin on activation of pro-MMP-2 and the cellular invasiveness in H-Ras-transformed MCF10A human breast epithelial cells. Here we show that fibronectin induces activation of pro-MMP-2 and up-regulation of MT1-MMP and TIMP-2 in H-Ras MCF10A cells. These results demonstrate that H-Ras MCF10A cells secrete high levels of active MMP-2 when cultured with fibronectin, suggesting a possible interaction between the ECM network and H-Ras MCF10A cells to generate active MMP-2 which is important for proteolysis and ECM remodeling. Invasive and migratory abilities of H-Ras MCF10A cells were enhanced by fibronectin. Fibronectin up-regulated the expression of ${\beta}1$ integrin which may play a role in cellular responses exerted by fibronectin. Since acquisition of pro-MMP-2 activation can be associated with increased malignant progression, this study provides a mechanism for the cell surface-matrix degrading effect of fibronectin which will be crucial to breast cell invasion and migration.

• 한국수정란이식학회지
• /
• 제13권2호
• /
• pp.179-190
• /
• 1998

Prolactin (PRL) surge in cycling rats at proestrous afternoon has previously been reported as an inducer of apoptotic cell death of luteal cells. This death-inducing action of PRL seeins unusual, because PRL can he categorized as a cell-survival factor, if other known physiological functions of PRL are taken into account. In this study, the apoptotic action of PRL was assessed in cultured cells prepared from rat luteal tissue and underlying molecular /cellular mechanism of PRL-induced luteolysis was analyzed. The latest crop of corpora lutea (CLs) were enucleated from rat ovaries at 18:00 h on the proestrous day before the next ovulation. Donor rats were pretreated with CB154, a dopamine agonist, in order to he exempted from the endogenous PRL surge. The harvested GLs were dispersed and cultured with or without PRL (2$\mu$g /ml) for 24 or 48 h. An addition of PRL to the culture medium changed the parameters indicative of cell death via apoptosis: a decrease in cell viability (MTT) and an increase in chromatin condensation. Most of the DNA breakdown in nuclei induced by PRL occurred in steroidogenic cells which were identified by 3$\beta$-HSD activity staining, and the number of 3$\beta$-HSD-positivecells were significantly decreased. Interestingly, most of the cells with an apoptotic nucleus adhered to one or more intact and seemingly non-steroidogenic cells. Because the expression of Fas has heen shown to be abundant in murine ovary, and Fas is known to have an exact physiological role in occurrence of apoptotic cell death, the membrane form-Fas ligand (rnFasL) was quantified in the cell lysate. An addition of PRL increased expression of mFasL. Moreover, an addition of concanavalin A (ConA), a T-cell specific activator, in place of PRL, enhanced the apoptotic parameters. Cumulatively, the apoptotic PRL action was addressed to cells unknown than steroidogenic lute~ cells. The most prohable candidate for the direct target cells is Tcells in the luteal tissue that can express mFasL in response to PRL.