377 research outputs found

    Substrate specificity provides insights into the sugar donor recognition mechanism of O-GlcNAc transferase (OGT).

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    O-Linked β-N-acetylglucosaminyl transferase (OGT) plays an important role in the glycosylation of proteins, which is involved in various cellular events. In human, three isoforms of OGT (short OGT [sOGT]; mitochondrial OGT [mOGT]; and nucleocytoplasmic OGT [ncOGT]) share the same catalytic domain, implying that they might adopt a similar catalytic mechanism, including sugar donor recognition. In this work, the sugar-nucleotide tolerance of sOGT was investigated. Among a series of uridine 5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc) analogs tested using the casein kinase II (CKII) peptide as the sugar acceptor, four compounds could be used by sOGT, including UDP-6-deoxy-GlcNAc, UDP-GlcNPr, UDP-6-deoxy-GalNAc and UDP-4-deoxy-GlcNAc. Determined values of Km showed that the substitution of the N-acyl group, deoxy modification of C6/C4-OH or epimerization of C4-OH of the GlcNAc in UDP-GlcNAc decreased its affinity to sOGT. A molecular docking study combined with site-directed mutagenesis indicated that the backbone carbonyl oxygen of Leu653 and the hydroxyl group of Thr560 in sOGT contributed to the recognition of the sugar moiety via hydrogen bonds. The close vicinity between Met501 and the N-acyl group of GlcNPr, as well as the hydrophobic environment near Met501, were responsible for the selective binding of UDP-GlcNPr. These findings illustrate the interaction of OGT and sugar nucleotide donor, providing insights into the OGT catalytic mechanism

    Universal factorial Schur P,QP,Q-functions and their duals

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    We define universal factorial Schur P,QP,Q-functions and their duals, which specialize to generalized (co)-homology "Schubert basis" for loop spaces of the classical groups. We also investigate some of their properties.Comment: 10 pages, old paper written in 2012.1

    Penciptaan Komunikasi Visual Perancangan Program Edutainment “Seri Aktivitas Alam: Gunung Meletus”

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    This research is the continuation of previous research. The research is included in the creation of visual communication solutions on how a process of visual communication strategy can contribute a persuasive invitation. Research aims to expose the solution in the realm of visual communication. The research applied qualitative method. It began with the development of communicators becoming a mascot, continued on the delivery of messages through the comics, and invited children as audience target for design experience with game and gimmick. Result of the research is the visual design, as well as including the process of visual communication creation. As a conclusion, creating a visual communication solution could be carried out by the same method, similar matching scope, as well as the contents adjusted with new needs

    Rnd3/RhoE Modulates HIF1α/VEGF Signaling by Stabilizing HIF1α and Regulates Responsive Cardiac Angiogenesis

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    The insufficiency of compensatory angiogenesis in the heart of patients with hypertension contributes to heart failure transition. The hypoxia-inducible factor 1α-vascular endothelial growth factor (HIF1α-VEGF) signaling cascade controls responsive angiogenesis. One of the challenges in reprograming the insufficient angiogenesis is to achieve a sustainable tissue exposure to the proangiogenic factors, such as HIF1α stabilization. In this study, we identified Rnd3, a small Rho GTPase, as a proangiogenic factor participating in the regulation of the HIF1α-VEGF signaling cascade. Rnd3 physically interacted with and stabilized HIF1α, and consequently promoted VEGFA expression and endothelial cell tube formation. To demonstrate this proangiogenic role of Rnd3 in vivo, we generated Rnd3 knockout mice. Rnd3 haploinsufficient (Rnd3(+/-)) mice were viable, yet developed dilated cardiomyopathy with heart failure after transverse aortic constriction stress. The poststress Rnd3(+/-) hearts showed significantly impaired angiogenesis and decreased HIF1α and VEGFA expression. The angiogenesis defect and heart failure phenotype were partially rescued by cobalt chloride treatment, a HIF1α stabilizer, confirming a critical role of Rnd3 in stress-responsive angiogenesis. Furthermore, we generated Rnd3 transgenic mice and demonstrated that Rnd3 overexpression in heart had a cardioprotective effect through reserved cardiac function and preserved responsive angiogenesis after pressure overload. Finally, we assessed the expression levels of Rnd3 in the human heart and detected significant downregulation of Rnd3 in patients with end-stage heart failure. We concluded that Rnd3 acted as a novel proangiogenic factor involved in cardiac responsive angiogenesis through HIF1α-VEGFA signaling promotion. Rnd3 downregulation observed in patients with heart failure may explain the insufficient compensatory angiogenesis involved in the transition to heart failure

    Backbone-modified molecular beacons for highly sensitive and selective detection of microRNAs based on duplex specific nuclease signal amplification

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    National Basic Research Program of China [2010CB732402, 2013CB933703]; National Science Foundation of China [21205100, 21275122]; National Instrumentation Program [2011YQ03012412]; Natural Science Foundation of Fujian Province for Distinguished Young Scholars [2010J06004]Based on backbone-modified molecular beacons and duplex-specific nuclease, we have developed a target recycling amplification method for highly sensitive and selective miRNA detection. The combination of a low fluorescence background of 2-OMe-RNA modified MB and nuclease-assisted signal amplification leads to ultrahigh assay sensitivity, and the powerful discriminating ability of MB enables the differentiation of highly similar miRNAs with one-base difference, both of which are of great significance to miRNA detection

    Chitosan microparticles gel for In vitro 3D culture of human chondrocytes

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    [EN] Chondrocytes are frequently cultured embedded in gels that provide them with a three-dimensional environment. Nevertheless cells in these constructs cannot remodel their neighbourhood when producing their own extracellular matrix. In this work we explore 3D environments that the cells can easily remodel. For this, human mature chondrocytes were cultured in the three-dimensional environment created by chitosan microparticles whose diameter is in the order of magnitude of the cell size. Chondrocytes and microparticles suspensions were mixed and the agglomerates were cultured in static tubes in chondrogenic medium. The poor adhesion between cells and chitosan surface maintained the mobility of the ensemble. In these conditions chondrocytes are viable during the 28 days of culture. The cells produce glycosaminoglycans, S100 and collagen type II up to 14 days of culture although production of type I collagen is also noticeable.J.L. Gomez Ribelles acknowledges the support of the Spanish Ministerio de Ciencia e Innovacion through MAT2010-21611-C03-00 project (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. N Garcia-Giralt acknowledges the support by grants from the Generalitat de Catalunya (DIUE 2009 SGR 818, 2009 SGR 971) and the Red Tematica de Investigacion Cooperativa en Envejecimiento y Fragilidad (RETICEF) and FEDER funds. Grand MAT2007-66759-C03-02 of Plan Nacional del MINISTERIO DE EDUCACION Y CIENCIA are also acknowledged.Garcia-Giralt, N.; García Cruz, DM.; Nogues, X.; Escobar Ivirico, JL.; Gómez Ribelles, JL. (2013). Chitosan microparticles gel for In vitro 3D culture of human chondrocytes. RSC Advances. 3(18):6362-6368. doi:10.1039/c3ra23173aS6362636831

    Fibronectin leucine-rich transmembrane protein 2 drives monocyte differentiation into macrophages via the UNC5B-Akt/mTOR axis

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    Upon migrating into the tissues, hematopoietic stem cell (HSC)-derived monocytes differentiate into macrophages, playing a crucial role in determining innate immune responses towards external pathogens and internal stimuli. However, the regulatory mechanisms underlying monocyte-to-macrophage differentiation remain largely unexplored. Here we divulge a previously uncharacterized but essential role for an axon guidance molecule, fibronectin leucine-rich transmembrane protein 2 (FLRT2), in monocyte-to-macrophage maturation. FLRT2 is almost undetectable in human monocytic cell lines, human peripheral blood mononuclear cells (PBMCs), and mouse primary monocytes but significantly increases in fully differentiated macrophages. Myeloid-specific deletion of FLRT2 (Flrt2ΔMyel) contributes to decreased peritoneal monocyte-to-macrophage generation in mice in vivo, accompanied by impaired macrophage functions. Gain- and loss-of-function studies support the promoting effect of FLRT2 on THP-1 cell and human PBMC differentiation into macrophages. Mechanistically, FLRT2 directly interacts with Unc-5 netrin receptor B (UNC5B) via its extracellular domain (ECD) and activates Akt/mTOR signaling. In vivo administration of mTOR agonist MYH1485 reverses the impaired phenotypes observed in Flrt2ΔMyel mice. Together, these results identify FLRT2 as a novel pivotal endogenous regulator of monocyte differentiation into macrophages. Targeting the FLRT2/UNC5B-Akt/mTOR axis may provide potential therapeutic strategies directly relevant to human diseases associated with aberrant monocyte/macrophage differentiation
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