The Experts below are selected from a list of 492201 Experts worldwide ranked by ideXlab platform
Rafael Balart - One of the best experts on this subject based on the ideXlab platform.
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Thermal properties comparison of hybrid CF/FF and BF/FF cyanate ester-based composites
Journal of Thermal Analysis and Calorimetry, 2018Co-Authors: D. Luca Motoc, Santiago Ferrándiz Bou, Rafael BalartAbstract:Insights within thermal expansion, conductivity, and decomposition dependencies with temperature on symmetrical and unsymmetrical layered carbon (CF) or basalt (BF) fabrics in combination with flax fibers (FF) were approached. Driven by commercial application and environmental concerns, the paper draws attention on a modified formula of cyanate ester with a common epoxy resin under an optimized ratio of 70:30 (vol%) as well as on the hybrid reinforcements stacking sequences. Synergetic effects were debated in terms of the CF and BF stacking sequences and corresponding volume fraction followed by comparisons with values predicted by the deployment of hybrid mixtures rules (RoHM/iRoHM). CF hybrid architectures revealed enhanced effective thermophysical properties over their BF counterparts and both over the FF-reinforced polymer composite considered as a reference. Thermal conductivities spread between 0.116 and 0.299 W m−1 K−1 from room temperature up to 250 °C on all hybrid specimens, giving rise to an insulator character. Concerning the coefficient of thermal expansion, CF hybrid architectures disclosed values of 1.236 10−6 K−1 and 3.102 10−6 K−1 compared with BF affine exhibiting 4.794 10−6 K−1 and 6.245 10−6 K−1, respectively, with an increase in their volume fraction.
Roberto Mantovani - One of the best experts on this subject based on the ideXlab platform.
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CONSTANS imparts DNA sequence specificity to the histone fold NF-YB/NF-YC dimer
The Plant cell, 2017Co-Authors: Nerina Gnesutta, Roderick W Kumimoto, Ben F Holt, Swadhin Swain, Matteo Chiara, Chamindika L. Siriwardana, David S. Horner, Roberto MantovaniAbstract:Nuclear Factor Y (NF-Y) is a heterotrimeric transcription factor that binds CCAAT elements. The NF-Y trimer is composed of a Histone Fold Domain (HFD) dimer (NF-YB/NF-YC) and NF-YA, which confers DNA sequence specificity. NF-YA shares a conserved domain with the CONSTANS, CONSTANS-LIKE, TOC1 (CCT) proteins. We show that CONSTANS (CO/B-BOX PROTEIN1 BBX1), a master flowering regulator, forms a trimer with Arabidopsis thaliana NF-YB2/NF-YC3 to efficiently bind the CORE element of the FLOWERING LOCUS T promoter. We term this complex NF-CO. Using saturation mutagenesis, electrophoretic mobility shift assays, and RNA-sequencing profiling of co, nf-yb, and nf-yc mutants, we identify CCACA elements as the core NF-CO binding site. CO physically interacts with the same HFD surface required for NF-YA association, as determined by mutations in NF-YB2 and NF-YC9, and tested in vitro and in vivo. The co-7 mutation in the CCT domain, corresponding to an NF-YA arginine directly involved in CCAAT recognition, abolishes NF-CO binding to DNA. In summary, a unifying molecular mechanism of CO function relates it to the NF-YA paradigm, as part of a trimeric complex imparting sequence specificity to HFD/DNA interactions. It is likely that members of the large CCT family participate in similar complexes with At-NF-YB and At-NF-YC, broadening HFD combinatorial possibilities in terms of trimerization, DNA binding specificities, and transcriptional regulation.
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Posttranslational Regulation of NF-YA Modulates NF-Y Transcriptional Activity
Molecular biology of the cell, 2008Co-Authors: Isabella Manni, Giuseppina Caretti, Simona Artuso, Aymone Gurtner, Velia Emiliozzi, Ada Sacchi, Roberto Mantovani, Giulia PiaggioAbstract:NF-Y binds to CCAAT motifs in the promoter region of a variety of genes involved in cell cycle progression. The NF-Y complex comprises three subunits, NF-YA, -YB, and -YC, all required for DNA binding. Expression of NF-YA fluctuates during the cell cycle and is down-regulated in postmitotic cells, indicating its role as the regulatory subunit of the complex. Control of NF-YA accumulation is posttranscriptional, NF-YA mRNA being relatively constant. Here we show that the levels of NF-YA protein are regulated posttranslationally by ubiquitylation and acetylation. A NF-YA protein carrying four mutated lysines in the C-terminal domain is more stable than the wild-type form, indicating that these lysines are ubiquitylated Two of the lysines are acetylated in vitro by p300, suggesting a competition between ubiquitylation and acetylation of overlapping residues. Interestingly, overexpression of a degradation-resistant NF-YA protein leads to sustained expression of mitotic cyclin complexes and increased cell proliferation, indicating that a tight regulation of NF-YA levels contributes to regulate NF-Y activity.
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The NF-YB/NF-YC structure gives insight into DNA binding and transcription regulation by CCAAT factor NF-Y.
The Journal of biological chemistry, 2002Co-Authors: Christophe Romier, Roberto Mantovani, Fabienne Cocchiarella, Dino MorasAbstract:The heterotrimeric transcription factor NF-Y recognizes with high specificity and affinity the CCAAT regulatory element that is widely represented in promoters and enhancer regions. The CCAAT box acts in concert with neighboring elements, and its bending by NF-Y is thought to be a major mechanism required for transcription activation. We have solved the structure of the NF-YC/NF-YB subcomplex of NF-Y, which shows that the core domains of both proteins interact through histone fold motifs. This histone-like pair is closely related to the H2A/H2B and NC2α/NC2β families, with features that are both common to this class of proteins and unique to NF-Y. The structure together with the modeling of the nonspecific interaction of NF-YC/NF-YB with DNA and the full NF-Y/CCAAT box complex highlight important structural features that account for different and possibly similar biological functions of the transcriptional regulators NF-Y and NC2. In particular, it emphasizes the role of the newly described αC helix of NF-YC, which is both important for NF-Y trimerization and a target for regulatory proteins, such as MYC and p53.
D. Luca Motoc - One of the best experts on this subject based on the ideXlab platform.
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Thermal properties comparison of hybrid CF/FF and BF/FF cyanate ester-based composites
Journal of Thermal Analysis and Calorimetry, 2018Co-Authors: D. Luca Motoc, Santiago Ferrándiz Bou, Rafael BalartAbstract:Insights within thermal expansion, conductivity, and decomposition dependencies with temperature on symmetrical and unsymmetrical layered carbon (CF) or basalt (BF) fabrics in combination with flax fibers (FF) were approached. Driven by commercial application and environmental concerns, the paper draws attention on a modified formula of cyanate ester with a common epoxy resin under an optimized ratio of 70:30 (vol%) as well as on the hybrid reinforcements stacking sequences. Synergetic effects were debated in terms of the CF and BF stacking sequences and corresponding volume fraction followed by comparisons with values predicted by the deployment of hybrid mixtures rules (RoHM/iRoHM). CF hybrid architectures revealed enhanced effective thermophysical properties over their BF counterparts and both over the FF-reinforced polymer composite considered as a reference. Thermal conductivities spread between 0.116 and 0.299 W m−1 K−1 from room temperature up to 250 °C on all hybrid specimens, giving rise to an insulator character. Concerning the coefficient of thermal expansion, CF hybrid architectures disclosed values of 1.236 10−6 K−1 and 3.102 10−6 K−1 compared with BF affine exhibiting 4.794 10−6 K−1 and 6.245 10−6 K−1, respectively, with an increase in their volume fraction.
Junsoo Park - One of the best experts on this subject based on the ideXlab platform.
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IRF-2 regulates NF-kappaB activity by modulating the subcellular localization of NF-kappaB
Cancer Research, 2008Co-Authors: Myounghee Chae, Kwang-soo Kim, Ik Soon Jang, Taegun Seo, Dong Min Kim, Il Chul Kim, Je Ho Lee, Yun-jee Seo, Junsoo ParkAbstract:5221 Nuclear Factor-kappa B (NF-κB) is a transcription factor essential to the control of cell proliferation, survival, differentiation, immune response, and inflammation. Constitutive NF-κB activation has been observed in a broad variety of solid tumors and hematological malignancies, which suggests that NF-κB signaling may perform a critical role in the development of human cancers. Interferon regulatory factor-2 (IRF-2), an antagonistic transcriptional repressor of IRF-1, evidences oncogenic potential, but little is currently known regarding the mechanism underlying the oncogenic activities of IRF-2. In this study, we report that IRF-2 recruits RelA/p65 transcription factors into the nucleus via physical interaction. While the nuclear recruitment of RelA by IRF-2 augments TNFα-induced NF-κB dependent transcription, the N-terminal truncated mutant form of IRF-2 inhibits the nuclear localization of RelA, and thus interferes with NF-κB activation. Furthermore, the knockdown of IRF-2 by IRF-2 siRNA attenuates TNFα-induced NF-κB dependent transcription by inhibiting the nuclear localization of RelA. Thus, these results show that IRF-2 regulates NF-κB activity via the modulation of NF-κB subcellular localization.
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IRF-2 regulates NF-κB activity by modulating the subcellular localization of NF-κB
Biochemical and biophysical research communications, 2008Co-Authors: Myounghee Chae, Kwang-soo Kim, Sun Mi Park, Ik Soon Jang, Taegun Seo, Dong Min Kim, Il Chul Kim, Je Ho Lee, Junsoo ParkAbstract:Nuclear Factor-kappa B (NF-kappaB) is a transcription factor essential to the control of cell proliferation, survival, differentiation, immune response, and inflammation. Constitutive NF-kappaB activation has been observed in a broad variety of solid tumors and hematological malignancies, which suggests that NF-kappaB signaling may perform a critical role in the development of human cancers. Interferon regulatory factor-2 (IRF-2), an antagonistic transcriptional repressor of IRF-1, evidences oncogenic potential, but little is currently known regarding the mechanism underlying the oncogenic activities of IRF-2. In this study, we report that IRF-2 recruits RelA/p65 transcription factors into the nucleus via physical interaction. While the nuclear recruitment of RelA by IRF-2 augments TNFalpha-induced NF-kappaB dependent transcription, the N-terminal truncated mutant form of IRF-2 inhibits the nuclear localization of RelA, and thus interferes with NF-kappaB activation. Furthermore, the knockdown of IRF-2 by IRF-2 siRNA attenuates TNFalpha-induced NF-kappaB dependent transcription by inhibiting the nuclear localization of RelA. Thus, these results show that IRF-2 regulates NF-kappaB activity via the modulation of NF-kappaB subcellular localization.
Steven C Ley - One of the best experts on this subject based on the ideXlab platform.
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Functions of NF-kappaB1 and NF-kappaB2 in immune cell biology.
The Biochemical journal, 2004Co-Authors: Sören Beinke, Steven C LeyAbstract:Two members of the NF-kappaB (nuclear factor kappaB)/Rel transcription factor family, NF-kappaB1 and NF-kappaB2, are produced as precursor proteins, NF-kappaB1 p105 and NF-kappaB2 p100 respectively. These are proteolytically processed by the proteasome to produce the mature transcription factors NF-kappaB1 p50 and NF-kappaB2 p52. p105 and p100 are known to function additionally as IkappaBs (inhibitors of NF-kappaB), which retain associated NF-kappaB subunits in the cytoplasm of unstimulated cells. The present review focuses on the latest advances in research on the function of NF-kappaB1 and NF-kappaB2 in immune cells. NF-kappaB2 p100 processing has recently been shown to be stimulated by a subset of NF-kappaB inducers, including lymphotoxin-beta, B-cell activating factor and CD40 ligand, via a novel signalling pathway. This promotes the nuclear translocation of p52-containing NF-kappaB dimers, which regulate peripheral lymphoid organogenesis and B-lymphocyte differentiation. Increased p100 processing also contributes to the malignant phenotype of certain T- and B-cell lymphomas. NF-kappaB1 has a distinct function from NF-kappaB2, and is important in controlling lymphocyte and macrophage function in immune and inflammatory responses. In contrast with p100, p105 is constitutively processed to p50. However, after stimulation with agonists, such as tumour necrosis factor-alpha and lipopolysaccharide, p105 is completely degraded by the proteasome. This releases associated p50, which translocates into the nucleus to modulate target gene expression. p105 degradation also liberates the p105-associated MAP kinase (mitogen-activated protein kinase) kinase kinase TPL-2 (tumour progression locus-2), which can then activate the ERK (extracellular-signal-regulated kinase)/MAP kinase cascade. Thus, in addition to its role in NF-kappaB activation, p105 functions as a regulator of MAP kinase signalling.
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Functions of NF-κB1 and NF-κB2 in immune cell biology
Biochemical Journal, 2004Co-Authors: Sören Beinke, Steven C LeyAbstract:Two members of the NF-κB (nuclear factor κB)/Rel transcription factor family, NF-κB1 and NF-κB2, are produced as precursor proteins, NF-κB1 p105 and NF-κB2 p100 respectively. These are proteolytically processed by the proteasome to produce the mature transcription factors NF-κB1 p50 and NF-κB2 p52. p105 and p100 are known to function additionally as IκBs (inhibitors of NF-κB), which retain associated NF-κB subunits in the cytoplasm of unstimulated cells. The present review focuses on the latest advances in research on the function of NF-κB1 and NF-κB2 in immune cells. NF-κB2 p100 processing has recently been shown to be stimulated by a subset of NF-κB inducers, including lymphotoxin-β, B-cell activating factor and CD40 ligand, via a novel signalling pathway. This promotes the nuclear translocation of p52-containing NF-κB dimers, which regulate peripheral lymphoid organogenesis and B-lymphocyte differentiation. Increased p100 processing also contributes to the malignant phenotype of certain T- and B-cell lymphomas. NF-κB1 has a distinct function from NF-κB2, and is important in controlling lymphocyte and macrophage function in immune and inflammatory responses. In contrast with p100, p105 is constitutively processed to p50. However, after stimulation with agonists, such as tumour necrosis factor-α and lipopolysaccharide, p105 is completely degraded by the proteasome. This releases associated p50, which translocates into the nucleus to modulate target gene expression. p105 degradation also liberates the p105-associated MAP kinase (mitogen-activated protein kinase) kinase kinase TPL-2 (tumour progression locus-2), which can then activate the ERK (extracellular-signal-regulated kinase)/MAP kinase cascade. Thus, in addition to its role in NF-κB activation, p105 functions as a regulator of MAP kinase signalling.