Solution Structure of Tensin2 SH2 Domain and Its Phosphotyrosine-Independent Interaction with DLC-1

Background: Src homology 2 (SH2) domain is a conserved module involved in various biological processes. Tensin family member was reported to be involved in tumor suppression by interacting with DLC-1 (deleted-in-liver-cancer-1) via its SH2 domain. We explore here the important questions that what the structure of tensin2 SH2 domain is, and how it binds to DLC-1, which might reveal a novel binding mode. Principal Findings: Tensin2 SH2 domain adopts a conserved SH2 fold that mainly consists of five b-strands flanked by two a-helices. Most SH2 domains recognize phosphorylated ligands specifically. However, tensin2 SH2 domain was identified to interact with nonphosphorylated ligand (DLC-1) as well as phosphorylated ligand. Conclusions: We determined the solution structure of tensin2 SH2 domain using NMR spectroscopy, and revealed the interactions between tensin2 SH2 domain and its ligands in a phosphotyrosine-independent manner

Supplementation of Vitamin E Protects Chickens from Newcastle Disease Virus-Mediated Exacerbation of Intestinal Oxidative Stress and Tissue Damage

BACKGROUND/AIMS: Newcastle disease virus (NDV) causes a highly devastating and contagious disease in poultry, which is mainly attributed to extensive tissue damages in the digestive, respiratory and nervous systems. However, nature and dynamics of NDV-induced oxidative stresses in the intestine of chickens remain elusive. METHODS: In this study, we examined the magnitude of intestinal oxidative stress and histopathological changes caused by the virulent NDV infection, and explored the protective roles of vitamin E (vit. E) in ameliorating these pathological changes. For these purposes, chickens were divided into four groups namely i) non supplemented and non-challenged (negative control, CON); ii) no supplementation of vit. E but challenged with ZJ1 (positive control, NS+CHA); iii) vit. E supplementation at the dose of 50 IU/day/Kg body weight and ZJ1 challenge (VE50+CHA); and 4) vit. E supplementation at the dose of 100 IU/day/Kg body weight and ZJ1 challenge (VE100+CHA). In all groups, we analyzed concentrations of glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (T-AOC), and activity of glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) using biochemical methods. The virus loads were determined by quantitative RT-PCR and antibody titers by hemagglutination inhibition assays. We also examined the histopathological changes in the duodenal and jejunal mucosa at 3 and 5-day post infection (dpi) with NDV. RESULTS: A significant elevation in the NO level was observed in NDV challenged chickens compared to the CON chickens at 2 dpi. The MDA contents were significantly increased whereas GSH was significantly decreased in NDV-challenged chickens compared to control. Furthermore, activities of GST, CAT, SOD, as well as the TOAC were markedly decreased in challenged chickens in comparison with control. Virus copy numbers were higher in NDV infected NS+CHA group compared to other groups. Severe histopathological changes including inflammation, degeneration and broken villi were observed in the intestine of NDV challenged chickens. However, all these malfunctions of antioxidant system and pathological changes in the intestine were partially or completely reversed by the vit. E supplementation. CONCLUSIONS: Our results suggest that NDV infection causes oxidative stress and histopathological changes in the duodenum and jejunum of chickens, which can be partially or fully ameliorated by supplementation of vit. E. Additionally, these findings suggest that oxidative stress contributes to the intestinal damages in NDV infected chickens. These findings will help to understand the pathogenesis of NDV and further investigation of therapeutic agents for control of Newcastle disease

Roadmap on spatiotemporal light fields

Spatiotemporal sculpturing of light pulse with ultimately sophisticated structures represents the holy grail of the human everlasting pursue of ultrafast information transmission and processing as well as ultra-intense energy concentration and extraction. It also holds the key to unlock new extraordinary fundamental physical effects. Traditionally, spatiotemporal light pulses are always treated as spatiotemporally separable wave packet as solution of the Maxwell's equations. In the past decade, however, more generalized forms of spatiotemporally nonseparable solution started to emerge with growing importance for their striking physical effects. This roadmap intends to highlight the recent advances in the creation and control of increasingly complex spatiotemporally sculptured pulses, from spatiotemporally separable to complex nonseparable states, with diverse geometric and topological structures, presenting a bird's eye viewpoint on the zoology of spatiotemporal light fields and the outlook of future trends and open challenges.Comment: This is the version of the article before peer review or editing, as submitted by an author to Journal of Optics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

YTH Domain: A Family of N6-methyladenosine (m6A) Readers

Like protein and DNA, different types of RNA molecules undergo various modifications. Accumulating evidence suggests that these RNA modifications serve as sophisticated codes to mediate RNA behaviors and many important biological functions. N6-methyladenosine (m6A) is the most abundant internal RNA modification found in a variety of eukaryotic RNAs, including but not limited to mRNAs, tRNAs, rRNAs, and long non-coding RNAs (lncRNAs). In mammalian cells, m6A can be incorporated by a methyltransferase complex and removed by demethylases, which ensures that the m6A modification is reversible and dynamic. Moreover, m6A is recognized by the YT521-B homology (YTH) domain-containing proteins, which subsequently direct different complexes to regulate RNA signaling pathways, such as RNA metabolism, RNA splicing, RNA folding, and protein translation. Herein, we summarize the recent progresses made in understanding the molecular mechanisms underlying the m6A recognition by YTH domain-containing proteins, which would shed new light on m6A-specific recognition and provide clues to the future identification of reader proteins of many other RNA modifications. Keywords: RNA modification, RNA methylation, RNA demethylation, YT521-B homology, Epitranscriptom

Structural comparison of TbCof with other ADF/cofilin family members.

<p>A. ADF/cofilin from <i>Trypanosoma brucei</i>; B. cofilin from <i>Saccharomyces cerevisiae</i> (PDB ID: 1COF); C. ADF1 from <i>Plasmodium falciparum</i> (PfADF1) (PDB ID: 2XF1); D. ADF2 from <i>Plasmodium berghei</i> (PbADF2) (PDB ID: 2XFA). These ADF/cofilin family members all share the classical fold except for a short helical turn in the loop between β6 and the C-terminal helix from residue D119 to L123 in TbCof and the shorter C-terminal region in PfADF1. The key secondary structure elements are labeled.</p

Model of TbCof (cyan) in complex with G-actin (magenta).

<p>The G-actin binding site contains 3 regions: a, the N-terminal extension that interacts with actin subdomain 1; b, the long kinked helix α3 that binds to the cleft between actin subdomains 1 and 3; c, the region before the C-terminal α-helix that interacts with actin subdomain 3. F-actin binding is mediated by additional regions consisting of the F-loop between β4-β5 (with label d) and the C-terminal α-helix (with label e). The F-actin binding site is circled by a dashed line.</p

Effect of TbCof on F-actin examined by electron microscopy.

<p>F-actin (5 µM) was incubated without (A) or with 0.05 µM TbCof (B), negatively stained with uranyl acetate, and observed by electron microscopy. Actin alone maintains long filaments. While only short filaments are observed in the presence of TbCof (B). The scale bars represent 100 nm.</p

NMR solution structure of TbCof.

<p>A. The lowest-energy conformation was used for the cartoon representation of TbCof, showing a central β sheet surrounded by α helices. The key secondary structure elements, both termini, and the F-loop are labeled; B. Superposition of backbone traces of the 20 lowest-energy NMR structures of TbCof. C. Electrostatic surface diagram of the lowest-energy conformation of TbCof is shown from two different orientations 180 degrees apart (red, negative; blue, positive; white, neutral).</p

Structural and Functional Insight into ADF/Cofilin from <em>Trypanosoma brucei</em>

<div><p>The ADF/cofilin family has been characterized as a group of actin-binding proteins critical for controlling the assembly of actin within the cells. In this study, the solution structure of the ADF/cofilin from <em>Trypanosoma brucei</em> (TbCof) was determined by NMR spectroscopy. TbCof adopts the conserved ADF/cofilin fold with a central β-sheet composed of six β-strands surrounded by five α-helices. Isothermal titration calorimetry experiments denoted a submicromolar affinity between TbCof and G-actin, and the affinity between TbCof and ADP-G-actin was five times higher than that between TbCof and ATP-G-actin at low ionic strength. The results obtained from electron microscopy and actin filament sedimentation assays showed that TbCof depolymerized but did not co-sediment with actin filaments and its ability of F-actin depolymerization was pH independent. Similar to actin, TbCof was distributed throughout the cytoplasm. All our data indicate a structurally and functionally conserved ADF/cofilin from <em>Trypanosoma brucei</em>.</p> </div