Neuronal BC RNAs cooperate with eIF4B to mediate activity-dependent translational control

In neurons, translational regulation of gene expression has been implicated in the activity-dependent management of synapto-dendritic protein repertoires. However, the fundamentals of stimulus-modulated translational control in neurons remain poorly understood. Here we describe a mechanism in which regulatory brain cytoplasmic (BC) RNAs cooperate with eukaryotic initiation factor 4B (eIF4B) to control translation in a manner that is responsive to neuronal activity. eIF4B is required for the translation of mRNAs with structured 5′ untranslated regions (UTRs), exemplified here by neuronal protein kinase Mζ (PKMζ) mRNA. Upon neuronal stimulation, synapto-dendritic eIF4B is dephosphorylated at serine 406 in a rapid process that is mediated by protein phosphatase 2A. Such dephosphorylation causes a significant decrease in the binding affinity between eIF4B and BC RNA translational repressors, enabling the factor to engage the 40S small ribosomal subunit for translation initiation. BC RNA translational control, mediated via eIF4B phosphorylation status, couples neuronal activity to translational output, and thus provides a mechanistic basis for long-term plastic changes in nerve cells.     

Ten years of co-management in Greek protected areas: an evaluation

The present study attempts an evaluation of the first co-management framework that has been adopted and implemented in Greece over the last 10 years for the management of its protected areas. To get insight as to how efficient it has been, we evaluate the performance and outcomes of the 28 management authorities of the protected areas of the country that substantiate it and the conditions under which they have been operating. The study involved a large part of the Greek conservation community. It was conducted via a questionnaire dealing with issues of financing and administration, environmental management and guarding, and connection with the local community. For co-management, it is essential that the actors involved undertake their share of responsibility, which should be clearly defined and delimited; this was not usually the case. Decentralization of the power of management requires capacity building locally and active involvement of the local community; these have been addressed and achieved only to a limited degree. Most importantly, the support and commitment to conservation of state actors were often missing. Funding discontinuities, delays in responding to needs associated with biodiversity monitoring and protection and inefficient guarding were the major problems resulting from the inadequacies detected. Despite its weaknesses, the co-management framework contributed considerably to the conservation of environmental values of Greece. We propose improvements and measures that can substantially increase its overall effectiveness towards nature conservation. However, under the severe crisis that the country has been facing, its future is currently unknown.     

Identification of otubain 1 as a novel substrate for the Yersinia protein kinase using chemical genetics and mass spectrometry

Yersinia encodes a protein kinase, YpkA, which disrupts the actin cytoskeleton. Using an approach termed chemical genetics, we identified a 36-kDa substrate for YpkA in both J774 lysates and bovine brain cytosol. Mass spectrometry analysis identified this substrate as FLJ20113, an open reading frame that corresponds to otubain 1, a deubiquitinating enzyme implicated in immune cell clonal anergy. We demonstrate that otubain 1 is phosphorylated by YpkA in vitro and interacts with YpkA and actin in vivo. Identification of otubain 1 as a YpkA substrate suggests that regulation of immune cell anergy may be a survival mechanism for Yersinia.     

Methylation-independent binding to histone H3 and cell cycle-dependent incorporation of HP1beta into heterochromatin

We have examined HP1beta-chromatin interactions in different molecular contexts in vitro and in vivo. Employing purified components we show that HP1beta exhibits selective, stoichiometric, and salt-resistant binding to recombinant histone H3, associating primarily with the helical "histone fold" domain. Furthermore, using "bulk" nucleosomes released by MNase digestion, S-phase extracts, and fragments of peripheral heterochromatin, we demonstrate that HP1beta associates more tightly with destabilized or disrupted nucleosomes (H3/H4 subcomplexes) than with intact particles. Western blotting and mass spectrometry data indicate that HP1beta-selected H3/H4 particles and subparticles possess a complex pattern of posttranslational modifications but are not particularly enriched in me3K9-H3. Consistent with these results, mapping of HP1beta and me3K9-H3 sites in vivo reveals overlapping, yet spatially distinct patterns, while transient transfection assays with synchronized cells show that stable incorporation of HP1beta-gfp into heterochromatin requires passage through the S-phase. The data amassed challenge the dogma that me3K9H3 is necessary and sufficient for HP1 binding and unveil a new mode of HP1-chromatin interactions.     

A high yield procedure for the preparation of arsonolipids (2,3-diacyloxypropylarsonic acids)

The crucial step in the preparation of the title arsonolipids starting from the dichloromethane-soluble dithioarsonite CH₂(OH)CH(OH)CH₂–As(SPh)₂ is to avoid an internal cyclization during the acylation which protects the primary –OH group from being acylated. This was to a large extent accomplished by using fatty acyl chloride in the presence of the weak base pyridine and controlling the temperature and rate of the acyl chloride addition, giving ～70% yields of arsonolipids. The presence of catalytic amounts of 4-dimethylaminopyridine boosted the yields to 82–85%. This yield is a great improvement over the yields (20–55%) previously achieved. The acylating systems (RCO)₂O or RCOCl and BF₃·Et₂O gave only moderate yields (25–60%) of arsonolipids.     

The effect of body size on the thermoregulation of lizards on hot,dry Mediterranean islands

Body size shapes the overall biology of organisms. We assessed the impact of size on temperature regulation in populations of normal-sized and large-bodied insular Mediterranean lizards (Podarcis gaigeae, Lacertidae). We hypothesized that large lizards would achieve higher body temperatures and thermoregulate more effectively than their smaller kin. Large- and small-bodied lizards share the same thermoregulation pattern, achieving similar body temperatures in the field. Large lizards, however, prefer higher set-point temperatures. Lizards in both populations thermoregulate effectively, but large lizards thermoregulated less effectively than normal-sized lizards. The particular conditions at the islet that harbors the large-bodied population (harsh intraspecific competition) seem to account for this pattern.     

Endosomal targeting of the phosphoinositide 3-phosphatase MTMR2 is regulated by an N-terminal phosphorylation site

MTMR2 is a member of the myotubularin family of inositol lipid phosphatases, a large protein-tyrosine phosphatase subgroup that is conserved from yeast to humans. Furthermore, the peripheral neuromuscular disease Charcot-Marie Tooth disease type 4B has been attributed to mutations in the mtmr2 gene. Because the molecular mechanisms regulating MTMR2 have been poorly defined, we investigated whether reversible phosphorylation might regulate MTMR2 function. We used mass spectrometry-based methods to identify a high stoichiometry phosphorylation site on serine 58 of MTMR2. Phosphorylation at Ser(58), or a phosphomimetic S58E mutation, markedly decreased MTMR2 localization to endocytic vesicular structures. In contrast, a phosphorylation-deficient MTMR2 mutant (S58A) displayed constitutive localization to early endocytic structures. This localization pattern was accompanied by displacement of a PI(3)P-specific sensor protein and an increase in signal transduction pathways. Thus, MTMR2 phosphorylation is likely to be a critical mechanism by which MTMR2 access to its lipid substrate(s) is temporally and spatially regulated, thereby contributing to the control of downstream endosome maturation events.     

Graft-Versus-Host Disease Prophylaxis after Transplantation: A Network Meta-Analysis

Background

Graft-versus-host Disease (GvHD) prophylaxis after allogeneic hematopoietic stem-cell transplantation (HSCT) is an ongoing effort but relative effects of different policies are not systematically explored.

Methods

We systematically reviewed 30-year evidence on GvHD prophylaxis and quantified the relative effect of different policies using a network meta-analysis. We searched PubMed and the Cochrane Library for randomized studies on the topic. The primary outcome of interest was grade II-IV acute GvHD over 0 or I (with odds ratio OR <1 denoting benefit).

Findings

Thirty-three eligible studies that enrolled 3,440 patients (published up to June 2014), provided data on seven immunosuppressive drugs namely cyclosporin A (CsA), methotrexate (MTX), anti-thymocyte globulin (ATG), mycophenolate mofetil (MMF), tacrolimus, sirolimus or corticosteroids and their combinations to calculate 14 direct and 21 indirect effects. The majority of trials (32/33) referred to myeloablative conditioning and sibling transplants (25/33). Tacrolimus/MTX (OR 0.44; 95% 0.27–0.70, number needed to treat to benefit, i.e. to avert a case of II-IV GvHD, NNTB = 5) and ATG/CsA/MTX (OR 0.45; 95%CI 0.26–0.78; NNTB = 5) were superior over CsA/MTX. ATG/CsA/MTX did not differ from tacrolimus/MTX (indirect evidence). Sirolimus-based prophylaxis outperformed CsA/MTX (OR 0.10; 95%CI 0.02–0.49, NNTB = 4) and marginally outperformed tacrolimus/MTX (OR 0.22; 95%CI 0.05–1.11). Add-on corticosteroids had no benefit over CsA/MTX.

Conclusions

Tacrolimus/MTX and ATG/CsA/MTX were the outperformers over CsA/MTX, but sirolimus-based regimens showed also potential. More randomized data are needed for reduced-intensity conditioning, as well as for MMF and sirolimus-containing regimens.