The Experts below are selected from a list of 32937 Experts worldwide ranked by ideXlab platform
Tero Ahola - One of the best experts on this subject based on the ideXlab platform.
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partially uncleaved alphavirus replicase forms spherule structures in the presence and absence of rna template
Journal of Virology, 2017Co-Authors: Kirsi Hellstrom, Katri Kallio, Age Utt, Tania Quirin, Eija Jokitalo, Andres Merits, Tero AholaAbstract:Alphaviruses are positive-strand RNA viruses expressing their replicase as a polyprotein, P1234, which is cleaved to four final products, nonstructural proteins nsP1 to nsP4. The replicase proteins together with viral RNA and host factors form Membrane invaginations termed spherules, which act as the replication complexes producing progeny RNAs. We have previously shown that the wild-type alphavirus replicase requires a functional RNA template and active polymerase to generate spherule structures. However, we now find that specific partially processed forms of the replicase proteins alone can give rise to Membrane invaginations in the absence of RNA or replication. The minimal requirement for spherule formation was the expression of properly cleaved nsP4, together with either uncleaved P123 or with the combination of nsP1 and uncleaved P23. These inactive spherules were morphologically less regular than replication-induced spherules. In the presence of template, nsP1 plus uncleaved P23 plus nsP4 could efficiently assemble active replication spherules producing both negative-sense and positive-sense RNA strands. P23 alone did not have Membrane affinity, but could be recruited to Membrane sites in the presence of nsP1 and nsP4. These results define the set of viral components required for alphavirus replication complex assembly and suggest the possibility that it could be reconstituted from separately expressed nonstructural proteins.IMPORTANCE All positive-strand RNA viruses extensively modify host cell Membranes to serve as efficient platforms for viral RNA replication. Alphaviruses and several other groups induce Protective Membrane invaginations (spherules) as their genome factories. Most positive-strand viruses produce their replicase as a polyprotein precursor, which is further processed through precise and regulated cleavages. We show here that specific cleavage intermediates of the alphavirus replicase can give rise to spherule structures in the absence of viral RNA. In the presence of template RNA, the same intermediates yield active replication complexes. Thus, partially cleaved replicase proteins play key roles that connect replication complex assembly, Membrane deformation, and the different stages of RNA synthesis.
Christos Gournas - One of the best experts on this subject based on the ideXlab platform.
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fungal plasma Membrane domains
Fems Microbiology Reviews, 2019Co-Authors: Alexandros Athanasopoulos, Bruno Andre, Vicky Sophianopoulou, Christos GournasAbstract:The plasma Membrane (PM) performs a plethora of physiological processes, the coordination of which requires spatial and temporal organization into specialized domains of different sizes, stability, protein/lipid composition and overall architecture. Compartmentalization of the PM has been particularly well studied in the yeast Saccharomyces cerevisiae, where five non-overlapping domains have been described: The Membrane Compartments containing the arginine permease Can1 (MCC), the H+-ATPase Pma1 (MCP), the TORC2 kinase (MCT), the sterol transporters Ltc3/4 (MCL), and the cell wall stress mechanosensor Wsc1 (MCW). Additional cortical foci at the fungal PM are the sites where clathrin-dependent endocytosis occurs, the sites where the external pH sensing complex PAL/Rim localizes, and sterol-rich domains found in apically grown regions of fungal Membranes. In this review, we summarize knowledge from several fungal species regarding the organization of the lateral PM segregation. We discuss the mechanisms of formation of these domains, and the mechanisms of partitioning of proteins there. Finally, we discuss the physiological roles of the best-known Membrane compartments, including the regulation of Membrane and cell wall homeostasis, apical growth of fungal cells and the newly emerging role of MCCs as starvation-Protective Membrane domains.
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conformation dependent partitioning of yeast nutrient transporters into starvation Protective Membrane domains
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Christos Gournas, Stelios Gkionis, Melanie Carquin, Laure Twyffels, Donatienne Tyteca, Bruno AndreAbstract:The eukaryotic plasma Membrane is compartmentalized into domains enriched in specific lipids and proteins. However, our understanding of the molecular bases and biological roles of this partitioning remains incomplete. The best-studied domain in yeast is the Membrane compartment containing the arginine permease Can1 (MCC) and later found to cluster additional transporters. MCCs correspond to static, furrow-like invaginations of the plasma Membrane and associate with subcortical structures named “eisosomes” that include upstream regulators of the target of rapamycin complex 2 (TORC2) in the sensing of sphingolipids and Membrane stress. However, how and why Can1 and other nutrient transporters preferentially segregate in MCCs remains unknown. In this study we report that the clustering of Can1 in MCCs is dictated by its conformation, requires proper sphingolipid biosynthesis, and controls its ubiquitin-dependent endocytosis. In the substrate-free outward-open conformation, Can1 accumulates in MCCs in a manner dependent on sustained biogenesis of complex sphingolipids. An arginine transport-elicited shift to an inward-facing conformation promotes its cell-surface dissipation and makes it accessible to the ubiquitylation machinery triggering its endocytosis. We further show that under starvation conditions MCCs increase in number and size, this being dependent on the BAR domain-containing Lsp1 eisosome component. This expansion of MCCs provides protection for nutrient transporters from bulk endocytosis occurring in parallel with autophagy upon TORC1 inhibition. Our study reveals nutrient-regulated protection from endocytosis as an important role for protein partitioning into Membrane domains.
Deyu Wang - One of the best experts on this subject based on the ideXlab platform.
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isophorone diisocyanate an effective additive to form cathode Protective interlayer and its influence on lini0 5co0 2mn0 3o2 at high potential
ACS Applied Materials & Interfaces, 2018Co-Authors: Jingjing Zhou, Deyu WangAbstract:In this work, we propose a novel electrolyte additive, isophorone diisocyanate (IPDI), to construct the surface Protective interlayer. This Membrane is produced via nucleophilic addition between the IPDI’s diisocyanate groups and the free-radical-onium ion oxidative intermediate of propylene carbonate (PC). In the electrolyte with IPDI added between 10–20 mM, LiNi0.5Co0.2Mn0.3O2 presents the excellent performance, demonstrating the relative wide operational window to form the optimal Protective Membrane. This Protective Membrane ameliorates the cyclic stability. Although all systems deliver ∼185 mAh g–1 under 1 C between 2.5–4.6 V (vs Li+/Li), the cells in the suitable electrolyte maintain 90.4% in the 50 cycles and 83.2% in the 200 cycles, whereas the control cells are seriously dropped to 73.4% and 69.8%. The cells in the electrolyte with the appropriate IPDI also present the good rate capability, attaining ∼143 mAh g–1 under 5 C, much higher than the cells in the control electrolyte(92.4 mAh g–1). The ...
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Isophorone Diisocyanate: An Effective Additive to Form Cathode-Protective-Interlayer and Its Influence on LiNi0.5Co0.2Mn0.3O2 at High Potential
2018Co-Authors: Yang Liu, Jingjing Zhou, Deyu Wang, Dandan Sun, Yinping Qin, Bingkun GuoAbstract:In this work, we propose a novel electrolyte additive, isophorone diisocyanate (IPDI), to construct the surface Protective interlayer. This Membrane is produced via nucleophilic addition between the IPDI’s diisocyanate groups and the free-radical-onium ion oxidative intermediate of propylene carbonate (PC). In the electrolyte with IPDI added between 10–20 mM, LiNi0.5Co0.2Mn0.3O2 presents the excellent performance, demonstrating the relative wide operational window to form the optimal Protective Membrane. This Protective Membrane ameliorates the cyclic stability. Although all systems deliver ∼185 mAh g–1 under 1 C between 2.5–4.6 V (vs Li+/Li), the cells in the suitable electrolyte maintain 90.4% in the 50 cycles and 83.2% in the 200 cycles, whereas the control cells are seriously dropped to 73.4% and 69.8%. The cells in the electrolyte with the appropriate IPDI also present the good rate capability, attaining ∼143 mAh g–1 under 5 C, much higher than the cells in the control electrolyte(92.4 mAh g–1). The additive proposed in this work is helpful to augment the energy density of lithium ion battery and prolong the one-drive distance of electric vehicles
Kirsi Hellstrom - One of the best experts on this subject based on the ideXlab platform.
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partially uncleaved alphavirus replicase forms spherule structures in the presence and absence of rna template
Journal of Virology, 2017Co-Authors: Kirsi Hellstrom, Katri Kallio, Age Utt, Tania Quirin, Eija Jokitalo, Andres Merits, Tero AholaAbstract:Alphaviruses are positive-strand RNA viruses expressing their replicase as a polyprotein, P1234, which is cleaved to four final products, nonstructural proteins nsP1 to nsP4. The replicase proteins together with viral RNA and host factors form Membrane invaginations termed spherules, which act as the replication complexes producing progeny RNAs. We have previously shown that the wild-type alphavirus replicase requires a functional RNA template and active polymerase to generate spherule structures. However, we now find that specific partially processed forms of the replicase proteins alone can give rise to Membrane invaginations in the absence of RNA or replication. The minimal requirement for spherule formation was the expression of properly cleaved nsP4, together with either uncleaved P123 or with the combination of nsP1 and uncleaved P23. These inactive spherules were morphologically less regular than replication-induced spherules. In the presence of template, nsP1 plus uncleaved P23 plus nsP4 could efficiently assemble active replication spherules producing both negative-sense and positive-sense RNA strands. P23 alone did not have Membrane affinity, but could be recruited to Membrane sites in the presence of nsP1 and nsP4. These results define the set of viral components required for alphavirus replication complex assembly and suggest the possibility that it could be reconstituted from separately expressed nonstructural proteins.IMPORTANCE All positive-strand RNA viruses extensively modify host cell Membranes to serve as efficient platforms for viral RNA replication. Alphaviruses and several other groups induce Protective Membrane invaginations (spherules) as their genome factories. Most positive-strand viruses produce their replicase as a polyprotein precursor, which is further processed through precise and regulated cleavages. We show here that specific cleavage intermediates of the alphavirus replicase can give rise to spherule structures in the absence of viral RNA. In the presence of template RNA, the same intermediates yield active replication complexes. Thus, partially cleaved replicase proteins play key roles that connect replication complex assembly, Membrane deformation, and the different stages of RNA synthesis.
Jingjing Zhou - One of the best experts on this subject based on the ideXlab platform.
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isophorone diisocyanate an effective additive to form cathode Protective interlayer and its influence on lini0 5co0 2mn0 3o2 at high potential
ACS Applied Materials & Interfaces, 2018Co-Authors: Jingjing Zhou, Deyu WangAbstract:In this work, we propose a novel electrolyte additive, isophorone diisocyanate (IPDI), to construct the surface Protective interlayer. This Membrane is produced via nucleophilic addition between the IPDI’s diisocyanate groups and the free-radical-onium ion oxidative intermediate of propylene carbonate (PC). In the electrolyte with IPDI added between 10–20 mM, LiNi0.5Co0.2Mn0.3O2 presents the excellent performance, demonstrating the relative wide operational window to form the optimal Protective Membrane. This Protective Membrane ameliorates the cyclic stability. Although all systems deliver ∼185 mAh g–1 under 1 C between 2.5–4.6 V (vs Li+/Li), the cells in the suitable electrolyte maintain 90.4% in the 50 cycles and 83.2% in the 200 cycles, whereas the control cells are seriously dropped to 73.4% and 69.8%. The cells in the electrolyte with the appropriate IPDI also present the good rate capability, attaining ∼143 mAh g–1 under 5 C, much higher than the cells in the control electrolyte(92.4 mAh g–1). The ...
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Isophorone Diisocyanate: An Effective Additive to Form Cathode-Protective-Interlayer and Its Influence on LiNi0.5Co0.2Mn0.3O2 at High Potential
2018Co-Authors: Yang Liu, Jingjing Zhou, Deyu Wang, Dandan Sun, Yinping Qin, Bingkun GuoAbstract:In this work, we propose a novel electrolyte additive, isophorone diisocyanate (IPDI), to construct the surface Protective interlayer. This Membrane is produced via nucleophilic addition between the IPDI’s diisocyanate groups and the free-radical-onium ion oxidative intermediate of propylene carbonate (PC). In the electrolyte with IPDI added between 10–20 mM, LiNi0.5Co0.2Mn0.3O2 presents the excellent performance, demonstrating the relative wide operational window to form the optimal Protective Membrane. This Protective Membrane ameliorates the cyclic stability. Although all systems deliver ∼185 mAh g–1 under 1 C between 2.5–4.6 V (vs Li+/Li), the cells in the suitable electrolyte maintain 90.4% in the 50 cycles and 83.2% in the 200 cycles, whereas the control cells are seriously dropped to 73.4% and 69.8%. The cells in the electrolyte with the appropriate IPDI also present the good rate capability, attaining ∼143 mAh g–1 under 5 C, much higher than the cells in the control electrolyte(92.4 mAh g–1). The additive proposed in this work is helpful to augment the energy density of lithium ion battery and prolong the one-drive distance of electric vehicles
