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101.
Zvi Schwartz Bryan F. Bell Liping Wang Ge Zhao Rene Olivares-Navarrete Barbara D. Boyan 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):606
Surface micron-scale and submicron scale features increase osteoblast differentiation and enhance responses of osteoblasts to 1,25-dihydroxyvitamin D3 [1α,25(OH)2D3]. β1 integrin expression is increased in osteoblasts grown on Ti substrates with rough microarchitecture, and it is regulated by 1α,25(OH)2D3 in a surface-dependent manner. To determine if β1 has a role in mediating osteoblast response, we silenced β1 expression in MG63 human osteoblast-like cells using small interfering RNA (siRNA). In addition, MG63 cells were treated with two different monoclonal antibodies to human β1 to block ligand binding. β1-silenced MG63 cells grown on a tissue culture plastic had reduced alkaline phosphatase activity and levels of osteocalcin, transforming growth factor β1, prostaglandin E2, and osteoprotegerin in comparison with control cells. Moreover, β1-silencing inhibited the effects of surface roughness on these parameters and partially inhibited effects of 1α,25(OH)2D3. Anti β1 antibodies decreased alkaline phosphatase but increase osteocalcin; effects of 1α,25(OH)2D3 on cell number and alkaline phosphatase were reduced and effects on osteocalcin were increased. These findings indicate that β1 plays a major and complex role in osteoblastic differentiation modulated by either surface microarchitecture or 1α,25(OH)2D3. The results also show that β1 mediates, in part, the synergistic effects of surface roughness and 1α,25(OH)2D3. 相似文献
102.
Cell polarization is essential for targeting signaling elements and organelles to active plasma membrane regions. In a few specialized cell types, cell polarity is enhanced by reorientation of the MTOC and associated organelles toward dynamic membrane sites. Phagocytosis is a highly polarized process whereby particles >0.5 microm are internalized at stimulated regions on the cell surface of macrophages. Here we provide detailed evidence that the MTOC reorients toward the site of particle internalization during phagocytosis. We visualized MTOC proximity to IgG-sRBCs in fixed RAW264.7 cells, during live cell imaging using fluorescent chimeras to label the MTOC and using frustrated phagocytosis assays. MTOC reorientation in macrophages is initiated by FcgammaR ligation and is complete within 1 h. Polarization of the MTOC toward the phagosome requires the MT cytoskeleton and dynein motor activity. cdc42, PI3K, and mPAR-6 are all important signaling molecules for MTOC reorientation during phagocytosis. MTOC reorientation was not essential for particle internalization or phagolysosome formation. However Golgi reorientation in concert with MTOC reorientation during phagocytosis implicates MTOC reorientation in antigen processing events in macrophages. 相似文献
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Crystal structure of quinone‐dependent alcohol dehydrogenase from Pseudogluconobacter saccharoketogenes. A versatile dehydrogenase oxidizing alcohols and carbohydrates
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Henriëtte J. Rozeboom Shukun Yu Rene Mikkelsen Igor Nikolaev Harm J. Mulder Bauke W. Dijkstra 《Protein science : a publication of the Protein Society》2015,24(12):2044-2054
The quinone‐dependent alcohol dehydrogenase (PQQ‐ADH, E.C. 1.1.5.2) from the Gram‐negative bacterium Pseudogluconobacter saccharoketogenes IFO 14464 oxidizes primary alcohols (e.g. ethanol, butanol), secondary alcohols (monosaccharides), as well as aldehydes, polysaccharides, and cyclodextrins. The recombinant protein, expressed in Pichia pastoris, was crystallized, and three‐dimensional (3D) structures of the native form, with PQQ and a Ca2+ ion, and of the enzyme in complex with a Zn2+ ion and a bound substrate mimic were determined at 1.72 Å and 1.84 Å resolution, respectively. PQQ‐ADH displays an eight‐bladed β‐propeller fold, characteristic of Type I quinone‐dependent methanol dehydrogenases. However, three of the four ligands of the Ca2+ ion differ from those of related dehydrogenases and they come from different parts of the polypeptide chain. These differences result in a more open, easily accessible active site, which explains why PQQ‐ADH can oxidize a broad range of substrates. The bound substrate mimic suggests Asp333 as the catalytic base. Remarkably, no vicinal disulfide bridge is present near the PQQ, which in other PQQ‐dependent alcohol dehydrogenases has been proposed to be necessary for electron transfer. Instead an associated cytochrome c can approach the PQQ for direct electron transfer. 相似文献
106.
Dimitra Gkika Loic Lemonnier George Shapovalov Dmitri Gordienko Céline Poux Michela Bernardini Alexandre Bokhobza Gabriel Bidaux Cindy Degerny Kathye Verreman Basma Guarmit Mohamed Benahmed Yvan de Launoit Rene J.M. Bindels Alessandra Fiorio Pla Natalia Prevarskaya 《The Journal of cell biology》2015,208(1):89-107
TRPM8 is a cold sensor that is highly expressed in the prostate as well as in other non-temperature-sensing organs, and is regulated by downstream receptor–activated signaling pathways. However, little is known about the intracellular proteins necessary for channel function. Here, we identify two previously unknown proteins, which we have named “TRP channel–associated factors” (TCAFs), as new TRPM8 partner proteins, and we demonstrate that they are necessary for channel function. TCAF1 and TCAF2 both bind to the TRPM8 channel and promote its trafficking to the cell surface. However, they exert opposing effects on TRPM8 gating properties. Functional interaction of TCAF1/TRPM8 also leads to a reduction in both the speed and directionality of migration of prostate cancer cells, which is consistent with an observed loss of expression of TCAF1 in metastatic human specimens, whereas TCAF2 promotes migration. The identification of TCAFs introduces a novel mechanism for modulation of TRPM8 channel activity. 相似文献
107.
Ester B. M. Remmerswaal Paul L. Klarenbeek Nuno L. Alves Marieke E. Doorenspleet Barbera D. C. van Schaik Rebecca E. E. Esveldt Mirza M. Idu Ester M. M. van Leeuwen Nelly van der Bom-Baylon Antoine H. C. van Kampen Sven D. Koch Hanspeter Pircher Frederike J. Bemelman Anja ten Brinke Frank Baas Ineke J. M. ten Berge Rene A.W. van Lier Niek de Vries 《Journal of virology》2015,89(1):568-580
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