1,721,394 research outputs found
A language model using variable length tokens for open-vocabulary Hangul text recognition
No full textWe propose a novel language model for Hangul text recognition. Without relying on prior linguistic knowledge in training, the proposed model learns variable length Hangul character sequences, which comprise the elementary tokens of Korean language, and their probabilities from statistics of a raw text corpus. Experiments in handwritten Hangul recognition shows that the proposed language model is effective in postprocessing of recognition results. (C) 2003 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved
ATP-induced focal adhesion kinase activity is negatively modulated by phospholipase D2 in PC12 cells
No full textExtracellular ATP has been known to modulate various cellular responses including mitogenesis, secretion and morphogenic activity in neuronal cells. In the ATP-incluced morphogenic activity, focal adhesion kinase(s) such as Fak have been suggested to play a critical role. Binding of ATP to its specific cell surface receptor in PC12 cells induces phospholipase D (PLO) activity. However, the role of PLD on ATP-induced Fak activation in PC12 cells remains unclear. In this study, we investigated the role of PLD on the ATP-induced Fak activation and paxillin phosphorylation using two established cell lines: wild type PLD2- and lipase-inactive mutant PLD2-inducible PC12 cells. Stimulation of cells with ATP caused PLD2 activation via classical protein kinase C activation. ATP also induced Fak activation, and paxillin phosphorylation, and were dramatically reduced by wild type PLD2 overexpression but not by lipase-inactive mutant PLD2 overexpression. When the PC12 cells were pretreated with propranolol, a specific inhibitor for phosphatidic acid phosphohydrolase resulting in the accumulation of PA, ATP-induced Fak-activation and paxillin phosphorylation were also reduced. We found that inhibition of tyrosine phosphatases by pervanadate completely blocked PLD2-dependent Fak and paxillin dephosphorylation. Taken together, we suggest that PLD2 activity might play a negative role in ATP-induced Fak and paxillin phosphorylation possibly through tyrosine phosphatases.open116sciescopuskc
Thimerosal induce focal adhesion kinase(FAK)-cleavage and apoptosis in Hela S cells
No full text110sciescopu
GTP-dependent interaction between phospholipase D and dynamin modulates fibronectin-induced cell spreading
No full textPhospholipase D (PLD) is one of the key enzymes to mediate a variety of cellular phenomena including endocytosis, actin rearrangement, proliferation, differentiation, and migration. Dynamin as a PLD-interacting partner is a large GTP binding protein that has been considered a mechanochemical enzyme involved in endocytosis by hydrolyzing GTP. Although both PLD and dynamin have been implicated in the regulation of actin cytoskeleton, it is not known how they have a link to regulate fibronectin (FN)-induced cell spreading. Furthermore, it is unknown whether dynamin can work as a GTP-dependent regulator through its interaction with other proteins. Here, we demonstrate that PLD can be regulated by dynamin in a GTP-dependent manner and that this is critical for FN-mediated cell spreading. First, we verified that GTP-loaded dynamin can mediate the cell spreading by FN by using dynamin's GTP binding deficient mutant (K44A). Also, we confirmed that blocking the PLD activity inhibited FN-induced cell spreading, not cell adhesion. Moreover, PLD interacted with dynamin in a GTP-dependent manner in FN signaling, and this interaction was crucial for FN-induced PLD activation and cell spreading. Also, we found that PLD mutant (R128K) that didn't have GAP activity increased the GTP-dependent interaction between PLD and dynamin; it also increased PLD activity and cell spreading. These findings suggest that the observed increase in PLD activity was through boosting the binding of PLD with dynamin and it facilitated FN-induced cell spreading. These results imply that GTP-loaded dynamin, like a small GTPase could mediate a "switch on" signaling via interaction with PLD that has a role as an effector. (C) 2015 Elsevier Inc. All rights reserved.1111sciescopu
The enhanced expression of IL-17-secreting T cells during the early progression of atherosclerosis in ApoE-deficient mice fed on a western-type diet
Get PDFAtherosclerosis is a chronic progressive inflammatory disorder and the leading cause of cardiovascular mortality. Here we assessed the dynamic changes of T-cell-derived cytokines, such as inteferon (IFN)-gamma, interleukin (IL)-17 and IL-4, during the progression of atherosclerosis in apolipoprotein E-null (ApoE(-/-)) mice, to understand the role of immune responses in different stages of atherosclerosis. Male ApoE(-/-) mice were fed a high-fat, western-type diet (WD: 21% lipid, 1.5% cholesterol) after 5 weeks of age and were compared with C57BL/6 wild-type control mice fed a standard chow diet. Atherosclerotic lesions appeared in the aortic sinus of ApoE(-/-) mice 4 weeks after WD and the lesions progressed and occupied > 50% of the total sinus area 16 weeks after WD. Aortic IL-17 mRNA and protein expression started to increase in ApoE(-/-) mice after 4 weeks on the WD and peaked at around 8-12 weeks on the WD. In terms of systemic expression of T-cell-derived cytokines, IL-17 production from splenocytes after anti-CD3/CD28 stimuli increased from 4 weeks on the WD, peaked at 12 weeks and returned to control levels at 16 weeks. The production of IFN-gamma and IL-4 (Th1 and Th2 cytokines, respectively) from splenocytes was delayed compared with IL-17. Taken together, the present data indicate that Th17 cell response may be involved at an early stage in the development of atherosclerosis.11911Ysciescopu
ASSAYS OF PHOSPHOINOSITIDE-SPECIFIC PHOSPHOLIPASE-C AND PURIFICATION OF ISOZYMES FROM BOVINE BRAINS
No full textX1152sciescopu
N-terminal site-specific mono-PEGylation of epidermal growth factor
No full textPurpose. N-terminal site-specific mono-PEGylation of recombinant human epidermal growth factor (EGF) was accomplished using polyethyleneglycol ( PEG) derivatives (Mw = 2000 and 5000) through a reactive terminal aldehyde group. Methods. The site-specific PEG conjugation was conducted at a slightly acidic pH condition (pH 5.5). The mono-PEGylation was targeted to an alpha-amine group at the N-terminal end of EGF to minimize reduction of biologic activity. Tryptic digestion mapping and MALDI-TOF MS techniques were applied to show the occurrence of mono-PEGylation at the N-terminus of EGF. Results. The site-specific mono-PEGylated EGF, when compared with native EGF, fully retained its in vitro biologic activities such as cell proliferation and intracellular signal transduction. This revealed that although a synthetic polymer of a PEG was covalently conjugated to EGF, the internalized complex of PEGylated EGF-receptor within cells did not hamper the intracellular signal transduction events. The PEGylated EGF also exhibited a prolonged circulation in blood stream in vivo and markedly enhanced physical stability when incubated with tissue homogenate. Conclusion. N-terminally mono-PEGylated EGF shows increased physical stability while retaining its biologic activity.X1191sciescopu
Promotion of monocyte survival by a chemoattractant peptide, WKYMVm: involvement of PKC-dependent Akt activation
No full text110sciescopu
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