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991.
The luminescence of novel rare earth ( Tb 3 + , Eu 3 + and Dy 3 + )‐activated Ba 2 Sr 2 Al 2 O 7 phosphors for solid‐state lighting is presented. The aluminate phosphors were synthesized using a one‐step combustion method. X‐Ray diffraction, scanning electron microscopy and photoluminescence characterizations were performed to understand the mechanism of excitation and the corresponding emission in the as‐prepared phosphor, as characterized the phase purity and microstructure. Improvements in the luminescence properties of the phosphors with rare earth concentration were observed. The phosphor hue could be tuned from blue, green and red by proper selection of rare earth ions in typical concentrations. Effective absorption in the near‐ultraviolet region was observed, which makes the phosphor a potential candidate for ultraviolet light‐emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
992.
Fu-Zheng Wei Ziyang Cao Xi Wang Hui Wang Mu-Yan Cai Tingting Li Naoko Hattori Donglai Wang Yipeng Du Boyan Song Lin-Lin Cao Changchun Shen Lina Wang Haiying Wang Yang Yang Dan Xie Fan Wang Toshikazu Ushijima Ying Zhao Wei-Guo Zhu 《Autophagy》2015,11(12):2309-2322
Macroautophagy is an evolutionarily conserved cellular process involved in the clearance of proteins and organelles. Although the autophagy regulation machinery has been widely studied, the key epigenetic control of autophagy process still remains unknown. Here we report that the methyltransferase EZH2 (enhancer of zeste 2 polycomb repressive complex 2 subunit) epigenetically represses several negative regulators of the MTOR (mechanistic target of rapamycin [serine/threonine kinase]) pathway, such as TSC2, RHOA, DEPTOR, FKBP11, RGS16 and GPI. EZH2 was recruited to these genes promoters via MTA2 (metastasis associated 1 family, member 2), a component of the nucleosome remodeling and histone deacetylase (NuRD) complex. MTA2 was identified as a new chromatin binding protein whose association with chromatin facilitated the subsequent recruitment of EZH2 to silenced targeted genes, especially TSC2. Downregulation of TSC2 (tuberous sclerosis 2) by EZH2 elicited MTOR activation, which in turn modulated subsequent MTOR pathway-related events, including inhibition of autophagy. In human colorectal carcinoma (CRC) tissues, the expression of MTA2 and EZH2 correlated negatively with expression of TSC2, which reveals a novel link among epigenetic regulation, the MTOR pathway, autophagy induction, and tumorigenesis. 相似文献
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995.
Cheuk-Yiu Law Chung-Wah Siu Katherine Fan Wing-Hon Lai Ka-Wing Au Yee-Man Lau Lai-Yung Wong Jenny C.Y. Ho Yee-ki Lee Hung-Fat Tse Kwong-Man Ng 《Biochemistry and Biophysics Reports》2016
Patients with Danon disease may suffer from severe cardiomyopathy, skeletal muscle dysfunction as well as varying degrees of mental retardation, in which the primary deficiency of lysosomal membrane-associated protein-2 (LAMP2) is considerably associated. Owing to the scarcity of human neurons, the pathological role of LAMP2 deficiency in neural injury of humans remains largely elusive. However, the application of induced pluripotent stem cells (iPSCs) may shed light on overcoming such scarcity.In this study, we obtained iPSCs derived from a patient carrying a mutated LAMP2 gene that is associated with Danon disease. By differentiating such LAMP2-deficient iPSCs into cerebral cortical neurons and with the aid of various biochemical assays, we demonstrated that the LAMP2-deficient neurons are more susceptible to mild oxidative stress-induced injury.The data from MTT assay and apoptotic analysis demonstrated that there was no notable difference in cellular viability between the normal and LAMP2-deficient neurons under non-stressed condition. When exposed to mild oxidative stress (10 μM H2O2), the LAMP2-deficient neurons exhibited a significant increase in apoptosis. Surprisingly, we did not observe any aberrant accumulation of autophagic materials in the LAMP2-deficient neurons under such stress condition.Our results from cellular fractionation and inhibitor blockade experiments further revealed that oxidative stress-induced apoptosis in the LAMP2-deficient cortical neurons was caused by increased abundance of cytosolic cathepsin L. These results suggest the involvement of lysosomal membrane permeabilization in the LAMP2 deficiency associated neural injury. 相似文献
996.
皮状丝孢酵母( Trichosporon cutaneum)能够同步利用葡萄糖和木糖生产油脂。以2脱氧葡萄糖(2 DOG)为底物,考察皮状丝孢酵母糖跨膜运输的转运动力学。结果表明:2 DOG转运符合米氏方程,表观米氏常数Km为0.19 mmol/L,最大转运速率Vmax为14.1 nmol/( min·mg)。葡萄糖和木糖均竞争性抑制2 DOG转运,葡萄糖表观抑制常数Ki远低于木糖,表明存在一个共用转运体系,且该转运体系对葡萄糖亲和力更高。大量木糖与2 DOG同时转运到胞内,进一步说明木糖与葡萄糖共运输。代谢抑制剂和pH对糖转运有明显影响,说明质子/底物同向运输系统是该酵母的主要糖转运系统。 相似文献
997.
Youjun Li Hao Zhou Fengzhi Li Siew Wee Chan Zhijie Lin Zhiyi Wei Zhou Yang Fusheng Guo Chun Jye Lim Wancai Xing Yuequan Shen Wanjin Hong Jiafu Long Mingjie Zhang 《Cell research》2015,25(7):801-817
The tumor suppressor Merlin/NF2 functions upstream of the core Hippo pathway kinases Lats1/2 and Mst1/2, as well as the nuclear E3 ubiquitin ligase CRL4DCAF1. Numerous mutations of Merlin have been identified in Neurofibromatosis type 2 and other cancer patients. Despite more than two decades of research, the upstream regulator of Merlin in the Hippo pathway remains unknown. Here we show by high-resolution crystal structures that the Lats1/2-binding site on the Merlin FERM domain is physically blocked by Merlin''s auto-inhibitory tail. Angiomotin binding releases the auto-inhibition and promotes Merlin''s binding to Lats1/2. Phosphorylation of Ser518 outside the Merlin''s auto-inhibitory tail does not obviously alter Merlin''s conformation, but instead prevents angiomotin from binding and thus inhibits Hippo pathway kinase activation. Cancer-causing mutations clustered in the angiomotin-binding domain impair angiomotin-mediated Merlin activation. Our findings reveal that angiomotin and Merlin respectively interface cortical actin filaments and core kinases in Hippo signaling, and allow construction of a complete Hippo signaling pathway. 相似文献
998.
Barbara Salani Silvia Ravera Adriana Amaro Annalisa Salis Mario Passalacqua Enrico Millo Gianluca Damonte Cecilia Marini Ulrich Pfeffer Gianmario Sambuceti Renzo Cordera Davide Maggi 《Cell cycle (Georgetown, Tex.)》2015,14(10):1559-1567
Pyruvate kinase M2 (PKM2) acts at the crossroad of growth and metabolism pathways in cells. PKM2 regulation by growth factors can redirect glycolytic intermediates into key biosynthetic pathway. Here we show that IGF1 can regulate glycolysis rate, stimulate PKM2 Ser/Thr phosphorylation and decrease cellular pyruvate kinase activity. Upon IGF1 treatment we found an increase of the dimeric form of PKM2 and the enrichment of PKM2 in the nucleus. This effect was associated to a reduction of pyruvate kinase enzymatic activity and was reversed using metformin, which decreases Akt phosphorylation. IGF1 induced an increased nuclear localization of PKM2 and STAT3, which correlated with an increased HIF1α, HK2, and GLUT1 expression and glucose entrapment. Metformin inhibited HK2, GLUT1, HIF-1α expression and glucose consumption. These findings suggest a role of IGFIR/Akt axis in regulating glycolysis by Ser/Thr PKM2 phosphorylation in cancer cells. 相似文献
999.
Tingbo Ding Inamul Kabir Yue Li Caixia Lou Amirfarbod Yazdanyar Jiachen Xu Jibin Dong Hongwen Zhou Taesik Park Mohamed Boutjdir Zhiqiang Li Xian-Cheng Jiang 《Journal of lipid research》2015,56(3):537-545
Sphingomyelin synthase-related protein (SMSr) synthesizes the sphingomyelin analog ceramide phosphoethanolamine (CPE) in cells. Previous cell studies indicated that SMSr is involved in ceramide homeostasis and is crucial for cell function. To further examine SMSr function in vivo, we generated Smsr KO mice that were fertile and had no obvious phenotypic alterations. Quantitative MS analyses of plasma, liver, and macrophages from the KO mice revealed only marginal changes in CPE and ceramide as well as other sphingolipid levels. Because SMS2 also has CPE synthase activity, we prepared Smsr/Sms2 double KO mice. We found that CPE levels were not significantly changed in macrophages, suggesting that CPE levels are not exclusively dependent on SMSr and SMS2 activities. We then measured CPE levels in Sms1 KO mice and found that Sms1 deficiency also reduced plasma CPE levels. Importantly, we found that expression of Sms1 or Sms2 in SF9 insect cells significantly increased not only SM but also CPE formation, indicating that SMS1 also has CPE synthase activity. Moreover, we measured CPE synthase Km and Vmax for SMS1, SMS2, and SMSr using different NBD ceramides. Our study reveals that all mouse SMS family members (SMSr, SMS1, and SMS2) have CPE synthase activity. However, neither CPE nor SMSr appears to be a critical regulator of ceramide levels in vivo. 相似文献
1000.
Kangmin He Xiaohua Yan Nan Li Song Dang Li Xu Bing Zhao Zijian Li Zhizhen Lv Xiaohong Fang Youyi Zhang Ye-Guang Chen 《Cell research》2015,25(6):738-752
Endocytosis and intracellular sorting of transforming growth factor-β (TGF-β) receptors play an important regulatory role in TGF-β signaling. Two major endocytic pathways, clathrin- and caveolae-mediated endocytosis, have been reported to independently mediate the internalization of TGF-β receptors. In this study, we demonstrate that the clathrin- and caveolae-mediated endocytic pathways can converge during TGF-β receptor endocytic trafficking. By tracking the intracellular dynamics of fluorescently-labeled TGF-β type I receptor (TβRI), we found that after mediating TβRI internalization, certain clathrin-coated vesicles and caveolar vesicles are fused underneath the plasma membrane, forming a novel type of caveolin-1 and clathrin double-positive vesicles. Under the regulation of Rab5, the fused vesicles are targeted to early endosomes and thus deliver the internalized TβRI to the caveolin-1 and EEA1 double-positive early endosomes (caveolin-1-positive early endosomes). We further showed that the caveolin-1-positive early endosomes are positive for Smad3/SARA, Rab11 and Smad7/Smurf2, and may act as a multifunctional device for TGF-β signaling and TGF-β receptor recycling and degradation. Therefore, these findings uncover a novel scenario of endocytosis, the direct fusion of clathrin-coated and caveolae vesicles during TGF-β receptor endocytic trafficking, which leads to the formation of the multifunctional sorting device, caveolin-1-positive early endosomes, for TGF-β receptors. 相似文献