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161.
162.
Yoshimi Tokuzawa Ken Yagi Yzumi Yamashita Yutaka Nakachi Itoshi Nikaido Hidemasa Bono Yuichi Ninomiya Yukiko Kanesaki-Yatsuka Masumi Akita Hiromi Motegi Shigeharu Wakana Tetsuo Noda Fred Sablitzky Shigeki Arai Riki Kurokawa Toru Fukuda Takenobu Katagiri Christian Sch?nbach Tatsuo Suda Yosuke Mizuno Yasushi Okazaki 《PLoS genetics》2010,6(7)
163.
Takashi Suzuki Koko Moriya Kei Nagatoshi Yoshinobu Ota Toru Ezure Eiji Ando Susumu Tsunasawa Toshihiko Utsumi 《Proteomics》2010,10(9):1780-1793
To establish a strategy for the comprehensive identification of human N‐myristoylated proteins, the susceptibility of human cDNA clones to protein N‐myristoylation was evaluated by metabolic labeling and MS analyses of proteins expressed in an insect cell‐free protein synthesis system. One‐hundred‐and‐forty‐one cDNA clones with N‐terminal Met‐Gly motifs were selected as potential candidates from ~2000 Kazusa ORFeome project human cDNA clones, and their susceptibility to protein N‐myristoylation was evaluated using fusion proteins, in which the N‐terminal ten amino acid residues were fused to an epitope‐tagged model protein. As a result, the products of 29 out of 141 cDNA clones were found to be effectively N‐myristoylated. The metabolic labeling experiments both in an insect cell‐free protein synthesis system and in the transfected COS‐1 cells using full‐length cDNA revealed that 27 out of 29 proteins were in fact N‐myristoylated. Database searches with these 27 cDNA clones revealed that 18 out of 27 proteins are novel N‐myristoylated proteins that have not been reported previously to be N‐myristoylated, indicating that this strategy is useful for the comprehensive identification of human N‐myristoylated proteins from human cDNA resources. 相似文献
164.
Functional and morphological responses of endothelial cells (ECs) to fluid shear stress are thought to be mediated by several mechanosensitive molecules. However, how the force due to fluid shear stress applied to the apical surface of ECs is transmitted to the mechanosensors is poorly understood. In the present paper, we performed an analysis of an intracellular mechanical field by observation of the deformation behaviors of living ECs exposed to shear stress with a novel experimental method. Lateral images of human umbilical vein ECs before and after the onset of flow were obtained by confocal microscopy, and image correlation and finite element analysis were performed for quantitative analyses of subcellular strain due to shear stress. The shear strain of the cells changed from 1.06 ± 1.09% (mean ± SD) to 4.67 ± 1.79% as the magnitude of the shear stress increased from 2 to 10 Pa. The nuclei of ECs also exhibited shear deformation, which was similar to that observed in cytoplasm, suggesting that nuclei transmit forces from apical to intracellular components, as well as cytoskeletons. The obtained strain-stress relation resulted in a mean shear modulus of 213 Pa for adherent ECs. These results provide a mechanical perspective on the investigation of flow-sensing mechanisms of ECs. 相似文献
165.
Yanli Mao Zhiguo Shang Yosuke Imai Ryugo Tero Motohiko Tanaka Naoki Yamamoto Katsuhiko Yanagisawa 《生物化学与生物物理学报:生物膜》2010,1798(6):1090-5929
Ganglioside GM1 mediates the amyloid beta (Aβ) aggregation that is the hallmark of Alzheimer's disease (AD). To investigate how ganglioside-containing lipid bilayers interact with Aβ, we examined the interaction between Aβ40 and supported planar lipid bilayers (SPBs) on mica and SiO2 substrates by using atomic force microscopy, fluorescence microscopy, and molecular dynamics computer simulations. These SPBs contained several compositions of sphingomyelin, cholesterol, and GM1 and were treated at physiological salt concentrations. Surprisingly high-speed Aβ aggregation of fibril formations occurred at all GM1 concentrations examined on the mica surface, but on the SiO2 surface, only globular agglomerates formed and they formed slowly. At a GM1 concentration of 20 mol%, unique triangular regions formed on the mica surface and the rapidly formed Aβ aggregations were observed only outside these regions. We have found that some unique surface-induced phase separations are induced by the GM1 clustering effects and the strong interactions between the GM1 head group and the water layer adsorbed in the ditrigonal cavities on the mica surface. The speed of Aβ40 aggregation and the shape of the agglomerates depend on the molecular conformation of GM1, which varies depending on the substrate materials. We identified the conformation that significantly accelerates Aβ40 aggregation, and we think that the detailed knowledge about the GM1 molecular conformation obtained in this work will be useful to those investigating Aβ-GM1 interactions. 相似文献
166.
Yosuke Ueki Yuhei Uda Masaaki Sato 《Biochemical and biophysical research communications》2010,395(3):441-446
Fluid shear stress (FSS) acting on the apical surface of endothelial cells (ECs) can be sensed by mechano-sensors in adhesive protein complexes found in focal adhesions and intercellular junctions. This sensing occurs via force transmission through cytoskeletal networks. This study quantitatively evaluated the force transmitted through cytoskeletons to the mechano-sensors by measuring the FSS-induced strain on SFs using live-cell imaging for actin stress fibers (SFs). FSS-induced bending of SFs caused the SFs to align perpendicular to the direction of the flow. In addition, the displacement vectors of the SFs were detected using image correlation and the FSS-induced axial strain of the SFs was calculated. The results indicated that FSS-induced strain on SFs spanned the range 0.01-0.1% at FSSs ranging from 2 to 10 Pa. Together with the tensile property of SFs reported in a previous study, the force exerted on SFs was estimated to range from several to several tens of pN. 相似文献
167.
Yosuke Ichijima Ken-ichi Yoshioka Yoshiko Yoshioka Keitaro Shinohe Hiroaki Fujimori Junya Unno Masatoshi Takagi Hidemasa Goto Masaki Inagaki Shuki Mizutani Hirobumi Teraoka 《PloS one》2010,5(1)
During tumorigenesis, cells acquire immortality in association with the
development of genomic instability. However, it is still elusive how genomic
instability spontaneously generates during the process of tumorigenesis. Here,
we show that precancerous DNA lesions induced by oncogene acceleration, which
induce situations identical to the initial stages of cancer development, trigger
tetraploidy/aneuploidy generation in association with mitotic aberration.
Although oncogene acceleration primarily induces DNA replication stress and the
resulting lesions in the S phase, these lesions are carried over into the M
phase and cause cytokinesis failure and genomic instability. Unlike directly
induced DNA double-strand breaks, DNA replication stress-associated lesions are
cryptogenic and pass through cell-cycle checkpoints due to limited and
ineffective activation of checkpoint factors. Furthermore, since damaged M-phase
cells still progress in mitotic steps, these cells result in chromosomal
mis-segregation, cytokinesis failure and the resulting tetraploidy generation.
Thus, our results reveal a process of genomic instability generation triggered
by precancerous DNA replication stress. 相似文献
168.
Iwata H Uga Y Yoshioka Y Ebana K Hayashi T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,114(8):1437-1449
One way to use a crop germplasm collection directly to map QTLs without using line-crossing experiments is the whole genome
association mapping. A major problem with association mapping is the presence of population structure, which can lead to both
false positives and failure to detect genuine associations (i.e., false negatives). Particularly in highly selfing species
such as Asian cultivated rice, high levels of population structure are expected and therefore the efficiency of association
mapping remains almost unknown. Here, we propose an approach that combines a Bayesian method for mapping multiple QTLs with
a regression method that directly incorporates estimates of population structure. That is, the effects due to both multiple
QTLs and population structure were included in our statistical model. We evaluated the efficiency of our approach in simulated-
and real-trait analyses of a rice germplasm collection. Simulation analyses based on real marker data showed that our model
could suppress both false-positive and false-negative rates and the error of estimation of genetic effects over single QTL
models, indicating that our model has statistically desirable attributes over single QTL models. As real traits, we analyzed
the size and shape of milled rice grains and found significant markers that may be linked to QTLs reported previously. Association
mapping should have good prospects in highly selfing species such as rice if proper methods are adopted. Our approach will
be useful for the whole genome association mapping of various selfing crop species. 相似文献
169.
Koseki M Hirano K Masuda D Ikegami C Tanaka M Ota A Sandoval JC Nakagawa-Toyama Y Sato SB Kobayashi T Shimada Y Ohno-Iwashita Y Matsuura F Shimomura I Yamashita S 《Journal of lipid research》2007,48(2):299-306
Lipid rafts on the cell surface are believed to be very important as platforms for various cellular functions. The aim of this study was to know whether defective lipid efflux may influence lipid rafts on the cell surface and their related cellular functions. We investigated macrophages with defective lipid efflux from ATP binding cassette transporter A1-deficient (Abca1-KO) mice. Lipid rafts were evaluated by the following two novel probes: a biotinylated and protease (subtilisin Carlsberg)-nicked derivative of theta-toxin and a fluorescein ester of polyethylene glycol-derived cholesterol. Lipid rafts in Abca1-KO macrophages were increased, as demonstrated by both probes. Moreover, activities of nuclear factor kappaB, mRNA and intracellular distribution, and secretion of tumor necrosis factor-alpha (TNF-alpha) were examined after stimulation by lipopolysaccharides (LPSs). LPS-induced responses of the activation of nuclear factor kappaB and TNF-alpha were more prompt and accelerated in the Abca1-KO macrophages compared with wild-type macrophages. Modification of lipid rafts by cyclodextrin and nystatin corrected the abnormal response, suggesting an association between the increased lipid rafts and abnormal TNF-alpha secretion. We report here that Abca1-KO macrophages with defective lipid efflux exhibited increased lipid rafts on the cell surface and accelerated TNF-alpha secretion. 相似文献
170.
Into T Kanno Y Dohkan J Nakashima M Inomata M Shibata K Lowenstein CJ Matsushita K 《The Journal of biological chemistry》2007,282(11):8134-8141
The endothelial cell-specific granule Weibel-Palade body releases vasoactive substances capable of modulating vascular inflammation. Although innate recognition of pathogens by Toll-like receptors (TLRs) is thought to play a crucial role in promotion of inflammatory responses, the molecular basis for early-phase responses of endothelial cells to bacterial pathogens has not fully been understood. We here report that human aortic endothelial cells respond to bacterial lipoteichoic acid (LTA) and synthetic bacterial lipopeptides, but not lipopolysaccharide or peptidoglycan, to induce Weibel-Palade body exocytosis, accompanied by release or externalization of the storage components von Willebrand factor and P-selectin. LTA could activate rapid Weibel-Palade body exocytosis through a TLR2- and MyD88-dependent mechanism without de novo protein synthesis. This process was at least mediated through MyD88-dependent phosphorylation and activation of phospholipase Cgamma. Moreover, LTA activated interleukin-1 receptor-associated kinase-1-dependent delayed exocytosis with de novo protein synthesis and phospholipase Cgamma-dependent activation of the NF-kappaB pathway. Increased TLR2 expression by transfection or interferon-gamma treatment increased TLR2-mediated Weibel-Palade body exocytosis, whereas reduced TLR2 expression under laminar flow decreased the response. Thus, we propose a novel role for TLR2 in induction of a primary proinflammatory event in aortic endothelial cells through Weibel-Palade body exocytosis, which may be an important step for linking innate recognition of bacterial pathogens to vascular inflammation. 相似文献