• Title/Summary/Keyword: translocation

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COMBINED LATTICE-BOLTZMANN AND MOLECULAR-DYNAMICS SIMULATION OF BIOPOLYMER TRANSLOCATION THROUGH AN ARTIFICIAL NANO-PORE (나노 세공을 지나는 생체고분자 운동에 대한 격자-볼츠만과 분자동역학에 의한 수치해석)

  • Alapati, Suresh;Kang, Sang-Mo;Suh, Yong-Kweon
    • 한국전산유체공학회:학술대회논문집
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    • pp.97-102
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    • 2009
  • Translocation of biopolymers such as DNA and RNA through a nano-pore is an important process in biotechnology applications. The translocation process of a biopolymer through an artificial nano-pore in the presence of a fluid solvent is simulated. The polymer motion is simulated by Langevin molecular dynamics (MD) techniques while the solvent dynamics are taken into account by lattice-Boltzmann method (LBM). The hydrodynamic interactions are considered explicitly by coupling the polymer and solvent through the frictional and the random forces. From simulation results we found that the hydrodynamic interactions between polymer and solvent speed-up the translocation process. The translocation time ${\tao}_T$ scales with the chain length N as ${{\tau}_T}^{\propto}N^{\alpha}$. The value of scaling exponents($\alpha$) obtained from our simulations are $1.29{\pm}0.03$ and $1.41{\pm}0.03$, with and without hydrodynamic interactions, respectively. Our simulation results are in good agreement with the experimentally observed value of $\alpha$, which is equal to $1.27{\pm}0.03$, particularly when hydrodynamic interaction effects are taken into account.

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RKIP Downregulation Induces the HBx-Mediated Raf-1 Mitochondrial Translocation

  • Kim, Sun-Young;Park, Sung-Goo;Jung, Hye-Yun;Chi, Seung-Wook;Yu, Dae-Yeul;Lee, Sang-Chul;Bae, Kwang-Hee
    • Journal of Microbiology and Biotechnology
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    • v.21 no.5
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    • pp.525-528
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    • 2011
  • The Raf-1 kinase inhibitory protein (RKIP) can regulate multiple key signaling pathways. Specifically, RKIP binds to Raf-1 kinase and inhibits the Ras-Raf-1-MEK1/2- ERK1/2 pathway. Additionally, Raf-1 has been shown to translocate to mitochondria and thereby protect cells from stress-mediated apoptosis. Recently, HBx was found to stimulate the mitochondrial translocation of Raf-1, contributing to the anti-apoptotic effect. We found that RKIP was downregulated during HBx-mediated hepatocarcinogenesis. In this study, we show that RKIP bound to Raf-1 and consequently inhibited the translocation of Raf-1 into mitochondria. This promoted the apoptosis of cells treated with apoptotic stimulus. Thus, the downregulation of RKIP increased the level of free Raf-1 and thereby elevated the mitochondrial translocation of Raf-1 during HBx-mediated hepatocarcinogenesis. The elevated Raf-1 mitochondrial translocation induced the increased anti-apoptotic effect and subsequently promoted HBx-mediated hepatocarcinogenesis.

Ursolic Acid Promotes Apoptosis of SGC-7901 Gastric Cancer Cells through ROCK/PTEN Mediated Mitochondrial Translocation of Cofilin-1

  • Li, Rui;Wang, Xia;Zhang, Xiao-Hong;Chen, Hong-Hai;Liu, Yan-Dong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.22
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    • pp.9593-9597
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    • 2014
  • Ursolic acid, extracted from the traditional Chinese medicine bearberry, can induce apoptosis of gastric cancer cells. However, its pro-apoptotic mechanism still needs further investigation. More and more evidence demonstrates that mitochondrial translocation of cofilin-1 appears necessary for the regulation of apoptosis. Here, we report that ursolic acid (UA) potently induces the apoptosis of gastric cancer SGC-7901 cells. Further mechanistic studies revealed that the ROCK1/PTEN signaling pathway plays a critical role in UA-mediated mitochondrial translocation of cofilin-1 and apoptosis. These findings imply that induction of apoptosis by ursolic acid stems primarily from the activation of ROCK1 and PTEN, resulting in the translocation of cofilin-1 from cytoplasm to mitochondria, release of cytochrome c, activation of caspase-3 and caspase-9, and finally inducing apoptosis of gastric cancer SGC-7901 cells.

A possible mechanism responsible for translocation and secretion an alkaliphilic bacillus sp. S-1 pullulanase

  • Shim, Jae-Kyoung;Kim, Kyoung-Sook;Kim, Cheorl-Ho
    • Journal of Microbiology
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    • v.35 no.3
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    • pp.213-221
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    • 1997
  • The secretion of the alkaliphilic Bacillus sp. S-1 extracellular pullulanase involves translocation across the cytoplasmic membrane of the Gram-positive bacterial cell envelope. Translocation of the intracellular pullulanase PUL-I, was traced to elucidate the mechanism and pathway of protein secretion from an alkaliphilic Bacillus sp. S-1. Pullulanase could be slowly bue quantitatively released into the medium during growth of the cells in medium contianing proteinase K. The released pullulanase lacked the N-terminal domain. The N-terminus is the sole membrane anchor in the pullulanase protein and was not affected by proteases, confirming that it is not exposed on the cell surface. Processing of a 180,000M$\_$r/ pullulanase to a 140,000M$\_$r/ polypeptide has been demonstrated in cell extracts using antibodies raised against 140,000M$\_$r/ extracellular form. Processing of the 180,000 M$\_$r/ protein occured during the preparation of extracts in an alkaline pH condition. A modified rapid extraction procedure suggested that the processing event also occured in vivo. Processing apparently increased the activity of pullulanase. The western blotting analysis with mouse anti-serum against 140-kDa extracellular pullulanase PUL-E showed that PUL-I is processed into PUL-X via intermediate form of PUL-E. Possible explanationa for the translocation are discussed.

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GLUT Phosphorylation May be Required to GLUT Translocation Mechanism

  • Hah, Jong-Sik
    • The Korean Journal of Physiology and Pharmacology
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    • v.4 no.6
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    • pp.497-506
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    • 2000
  • In this work, GLUTs phosphorylations by a downstream effector of PI3-kinase, $PKC-{\zeta},$ were studied, and GLUT4 phosphorylation was compared with GLUT2 phosphorylation in relation to the translocation mechanism. Prior to phosphorylation experiment, $PKC-{\zeta}$ kinase activity was determined as $20.76{\pm}4.09$ pmoles Pi/min/25 ng enzymes. GLUT4 was phosphorylated by $PKC-{\zeta}$ and the phosphorylation was increased on the vesicles immunoadsorpted from LDM and on GLUT4 immunoprecipitated from GLUT4- contianing vesicles of adipocytes treated with insulin. However, GLUT2 in hepatocytes was neither phosphorylated by $PKC-{\zeta}$ nor changed in response to insulin treatment. It was confirmed by measuring the subcellular distribution of GLUT2 based on GLUT2 immunoblot density among the four membrane fractions before and after insulin treatment. Total GLUT2 distributions at PM, LYSO, HDM and LDM were $37.7{\pm}12.0%,\;42.4{\pm}12.1%,\;19.2{\pm}5.0%\;and\;0.7{\pm}1.2%$ in the absence of insulin. Total GLUT2 distribution in the presence of insulin was almost same as that in the absence of insulin. Present data with previous findings suggest that GLUT4 translocation may be attributed to GLUT4 phosphorylation by $PKC-{\zeta}$ but GLUT2 does not translocate because GLUT2 is not phosphorylated by the kinase. Therefore, GLUT phosphorylation may be required in GLUT translocation mechanism.

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Evaluation of Toxicity of Green Tea Extract in Chilled Boar Spermatozoa

  • Park, Sang-Hyoun;Yu, Il-Jeoung
    • Journal of Embryo Transfer
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    • v.30 no.1
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    • pp.1-6
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    • 2015
  • The cold shock of spermatozoa is associated with oxidative stress induced by reactive oxygen species. This study was conducted to evaluate the toxicity of natural antioxidant green tea extract (GTE) in lactose-egg yolk (LEY) extender during boar sperm cooling prior to freezing. Spermatozoa were cooled to $5^{\circ}C$ for 3 h in LEY extender containing 0 (control), 1, 10, 100 or 1,000 mg/l of GTE, re-suspended with LEY-glycerol-Equex extender and cooled at $5^{\circ}C$ for 30 min. Sperm progressive motility, viability and phosphatidylserine (PS) translocation were evaluated. PS translocation was assayed by flow cytometry using Annexin V-FITC apoptosis detection kit. The sperm function including progressive motility, viability and PS translocation was not significantly different regardless of GTE concentrations (P>0.05). In conclusion, this study demonstrated non-toxicity of GTE supplement in LEY extender during sperm cooling.

Ankylosing spondylitis associated with balanced reciprocal X-1 translocation (X염색체와 1번 염색체간 균형전위와 동반된 강직척추염)

  • Kim, Young Hoon;Lee, Jung Ouk
    • Yeungnam University Journal of Medicine
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    • v.34 no.1
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    • pp.80-83
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    • 2017
  • A number of research papers have reported more frequent occurrence of rheumatic/autoimmune disease among patients with hypogonadism or a chromosomal anomaly with potential X-chromosome defects. A 30-year-old female patient came to the hospital with a main cause of bilateral buttock pain, which began two years ago and worsened seven days ago. Ankylosing spondylitis with invasion of both sacral-iliac joints was observed. On magnetic resonance imaging, although the uterus was observed normally, an ovary was not observed. In a chromosome test, balanced reciprocal X-1 translocation of 46,X,t(X;1)(p10;q10) was diagnosed. Here, we report on the first case involving ankylosing spondylitis accompanied by balanced reciprocal X-1 translocation.

Sprengel's deformity associated with a de novo balanced translocation involving chromosome 3 and 17 (선천성 고위 견갑골을 동반한 3번과 17번 염색체의 균형전좌 1례)

  • Jung, On;Lee, Jung-Hyun;Chun, Chung-Sik
    • Clinical and Experimental Pediatrics
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    • v.50 no.3
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    • pp.311-315
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    • 2007
  • This is the first case of a de novo balanced translocation 46, XY, t(3;17)(p12.2;q25) associated with multiple musculoskeletal abnormalities, including Sprengel's deformity (congenital undescended scapula to be reported). This translocation has not been described previously with this congenital anomaly in Korea.

Oxalate Decarboxylase from Agrobacterium tumefaciens C58 is Translocated by a Twin Arginine Translocation System

  • Shen, Yu-Hu;Liu, Rui-Juan;Wang, Hai-Qing
    • Journal of Microbiology and Biotechnology
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    • v.18 no.7
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    • pp.1245-1251
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    • 2008
  • Oxalate decarboxylases (OXDCs) (E.C. 4.1.1.2) are enzymes catalyzing the conversion of oxalate to formate and $CO_2$. The OXDCs found in fungi and bacteria belong to a functionally diverse protein superfamily known as the cupins. Fungi-originated OXDCs are secretory enzymes. However, most bacterial OXDCs are localized in the cytosol, and may be involved in energy metabolism. In Agrobacterium tumefaciens C58, a locus for a putative oxalate decarboxylase is present. In the study reported here, an enzyme was overexpressed in Escherichia coli and showed oxalate decarboxylase activity. Computational analysis revealed the A. tumefaciens C58 OXDC contains a signal peptide mediating translocation of the enzyme into the periplasm that was supported by expression of signal-peptideless and full-length versions of the enzyme in A. tumefaciens C58. Further site-directed mutagenesis experiment demonstrated that the A. tumefaciens C58 OXDC is most likely translocated by a twin-arginine translocation (TAT) system.

Temporal Characteristics of Cytosolic Translocation of Mitochondrial Proteins in Permanent Distal Middle Cerebral Artery Occlusion Model of Rats

  • Shin, Byoung-Wook;Sung, Jae-Hoon;Hong, Jae-Taek;Son, Byung-Chul;Lee, Sang-Won;Park, Chun-Kun
    • Journal of Korean Neurosurgical Society
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    • v.41 no.5
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    • pp.306-313
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    • 2007
  • Objective : In permanent distal middle cerebral artery occlusion [pdMCAO] model of rats, the temporal order of subcellular translocation is not fully understood yet. We studied translocation sequence of cytochrome c and apoptosis inducing factor [AIF] after pdMCAO and patterns of expression. Methods : Twenty-one male rats - with ten minutes, 1, 4, 8, 24 and 48 hours of pdMCAO groups - were enrolled. At core and penumbra area of each cerebral cortex, Western blotting of cytochrome c and AIF were performed using cytosolic fractions and then compared with sham specimens. With 48 hours group, the expression of cytochrome c and AIF was examined with immunofluorescent staining. Results : Compared to sham, the cytosolic translocation of cytochrome c significantly increased at all time points [p<0.05]. As early as 10 min after onset of ischemia, it was increased significantly [p<0.01]. The cytosolic translocation of AIF showed gradual increase with the passage of time and significantly increased 8 hours after [p<0.05]. As late as 24 hours and 48 hours after onset of ischemia, there were increased most significantly [p<0.01]. At penumbra, both proteins failed to show significant increase at all time points. At 48 hours after ischemia, colocalization of cytochrome c and AIF were confirmed. Conclusion : Cytosolic translocation of cytochrome c peaks much earlier than that of AIF in pdMCAO model of rat. Caspase dependent apoptosis activates soon after ischemia and later, it can be reinforced by gradually increasing AIF in ischemic core.