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871.
Lim MJ Seo YH Choi KJ Cho CH Kim BS Kim YH Lee J Lee H Jung CY Ha J Kang I Kim SS 《Archives of biochemistry and biophysics》2007,465(1):197-208
Role of c-Src in muscle differentiation has been controversial. Here, we investigated if c-Src positively or negatively regulates muscle differentiation, using H9c2 and C2C12 cell lines. Inhibition of c-Src by treatment with PP1 and SU6656, pharmacologic inhibitors of Src family kinases, or by expression of a dominant negative c-Src, all induced muscle differentiation in proliferation medium (PM). In differentiating cells in differentiation medium (DM), c-Src activity gradually decreased and reached basal level 3 days after induction of differentiation. Inhibition of c-Src suppressed Raf/MEK/ERK pathway but activated p38 MAPK. Inhibition of p38 MAPK did not affect c-Src activity in PM. However, it reactivated Raf/MEK/ERK pathway in c-Src-inhibited cells regardless of PM or DM. Concomitant inhibition of c-Src and p38 MAPK activities blocked muscle differentiation in both media. In conclusion, suppression of c-Src activity stimulates muscle differentiation by activating p38 MAPK uni-directionally. 相似文献
872.
873.
874.
Wu J Zhang X Zhang L Wu CY Rezaeian AH Chan CH Li JM Wang J Gao Y Han F Jeong YS Yuan X Khanna KK Jin J Zeng YX Lin HK 《Molecular cell》2012,46(3):351-361
The Mre11/Rad50/NBS1 (MRN) complex is thought to be a critical sensor that detects damaged DNA and recruits ATM to DNA foci for activation. However, it remains to be established how the MRN complex regulates ATM recruitment to the DNA foci during DNA double-strand breaks (DSBs). Here we show that Skp2 E3 ligase is a key component for the MRN complex-mediated ATM activation in response to DSBs. Skp2 interacts with NBS1 and triggers K63-linked ubiquitination of NBS1 upon DSBs, which is critical for the interaction of NBS1 with ATM, thereby facilitating ATM recruitment to the DNA foci for activation. Finally, we show that Skp2 deficiency exhibits a defect in homologous recombination (HR) repair, thereby increasing IR sensitivity. Our results provide molecular insights into how Skp2 and the MRN complex coordinate to activate ATM, and identify Skp2-mediatetd NBS1 ubiquitination as a vital event for ATM activation in response to DNA damage. 相似文献
875.
876.
The bioassay-guided purification of ether extracts of Alpinia officinarum led to the isolation of two new compounds 6-hydroxy-1,7-diphenyl-4-en-3-heptanone (1) and 6-(2-hydroxy-phenyl)-4-methoxy-2-pyrone (4) as well as three known compounds 1,7-diphenyl-4-en-3-heptanone (2), 1,7-diphenyl-5-methoxy-3-heptanone (3), and apigenin (5). Their structures were established on the basis of spectral methods. All three diarylheptanoids 1, 2, and 3 exhibited potent PAF receptor binding inhibitory activities with an IC50 of 1.3, 5.0, and 1.6 μM, respectively. These studies have identified diarylheptanoids as a novel class of potent PAF antagonists. 相似文献
877.
Down-regulation of gp96 by Orientia tsutsugamushi 总被引:2,自引:0,他引:2
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879.
A theoretical model equation was derived to find the correlation between the conversion and the amount of immobilized penicillin amidase in column. The theoretical values of the conversion were predicted form this correlation and compared with experimental results. It was observed in a column reactor that the pH drop along the column path was linear versus the enzyme loading and that the enzyme activity was also linearly dependent on pH up to 8.0. In order to diminish the effect of pH drop, a continuous two-stage plug-flow reactor (PFR) with pH adjustment between the two columns was used was used in the experiments, and two- and three-stage PFRs were simulated by computer. In the case of the two-stage PFR, the maximum productivity was demonstrated experimentally and theoretically as well. when an equal amount of the immobilized enzyme was packed in both columns. It was also predicted in the tree-stage PFR system that the optimal distributions of enzyme loading in three columns were found to be 1:1:1. It was demonstrated that the increased number of reactors in series could enhance the level of the maximum productivity with a given amount of enzyme loading. 相似文献
880.
Choong Hyun Lee In Koo Hwang Ki-Yeon Yoo Jung Hoon Choi Ok Kyu Park Jae-Chul Lee Young-Gil Jeong In Se Lee Moo-Ho Won 《Cellular and molecular neurobiology》2009,29(5):665-672
The hippocampus is associated with learning and memory function and shows neurochemical changes in aging processes. Calbindin
D-28k (CB) binds calcium ion with a fast association rate. We examined age-related changes in CB immunoreactivity and its
protein level in the gerbil hippocampus during normal aging. In the hippocampal CA1 region (CA1) and CA2, CB immunoreaction
was found in some neurons in the stratum pyramidale (SP) at postnatal month 1 (PM 1). CB immunoreactivity in neurons was markedly
increased at PM 3. Thereafter, CB immunoreactivity was decreased with time: CB-immunoreactive (+) neurons were fewest at PM 24. In the CA3, a few CB+ neurons were found only in the SP at PM 1 and in the stratum radiatum at PM 18 and 24. In addition, mossy fibers were stained
with CB at PM 1. CB immunoreactivity in mossy fibers was markedly increased at PM 3, thereafter it was decreased with time.
In the dentate gyrus, many granule cells (GC) in the granule cell layer were stained with CB at PM 1. CB immunoreactivity
in GC was markedly increased at PM 3, thereafter CB immunoreactivity was decreased with time. In Western blot analysis, CB
protein level in the gerbil hippocampus was highest at PM 3, thereafter CB protein levels were decreased with time. This result
indicates that CB in the gerbil hippocampus is abundant at PM 3 and is decreased with age. 相似文献