Ubiquitination and sumoylation of the HTLV-2 Tax-2B protein regulate its NF-κB activity: a comparative study with the HTLV-1 Tax-1 protein.

BACKGROUND:Retroviruses HTLV-1 and HTLV-2 have homologous genomic structures but differ significantly in pathogenicity. HTLV-1 is associated with Adult T cell Leukemia (ATL), whereas infection by HTLV-2 has no association with neoplasia. Transformation of T lymphocytes by HTLV-1 is linked to the capacity of its oncoprotein Tax-1 to alter cell survival and cell cycle control mechanisms. Among these functions, Tax-1-mediated activation of cellular gene expression via the NF-κB pathway depends on Tax-1 post-translational modifications by ubiquitination and sumoylation. The Tax-2 protein of HTLV-2B (Tax-2B) is also modified by ubiquitination and sumoylation and activates the NF-κB pathway to a level similar to that of Tax-1. The present study aims to understand whether ubiquitination and sumoylation modifications are involved in Tax-2B-mediated activation of the NF-κB pathway.RESULTS:The comparison of Tax-1 and Tax-2B lysine to arginine substitution mutants revealed conserved patterns and levels of ubiquitination with notable difference in the lysine usage for sumoylation. Neither Tax-1 nor Tax-2B ubiquitination and sumoylation deficient mutants could activate the NF-κB pathway and fusion of ubiquitin or SUMO-1 to the C-terminus of the ubiquitination and sumoylation deficient Tax-2B mutant strikingly restored transcriptional activity. In addition, ubiquitinated forms of Tax-2B colocalized with RelA and IKKγ in prominent cytoplasmic structures associated with the Golgi apparatus, whereas colocalization of Tax-2B with the RelA subunit of NF-κB and the transcriptional coactivator p300 in punctate nuclear structures was dependent on Tax-2B sumoylation, as previously observed for Tax-1.CONCLUSIONS:Both Tax-1 and Tax-2 activate the NF-κB pathway via similar mechanisms involving ubiquitination and sumoylation. Therefore, the different transforming potential of HTLV-1 and HTLV-2 is unlikely to be related to different modes of activation of the canonical NF-κB pathway

On the conservation of the slow conformational dynamics within the amino acid kinase family: NAGK the paradigm

N-Acetyl-L-Glutamate Kinase (NAGK) is the structural paradigm for examining the catalytic mechanisms and dynamics of amino acid kinase family members. Given that the slow conformational dynamics of the NAGK (at the microseconds time scale or slower) may be rate-limiting, it is of importance to assess the mechanisms of the most cooperative modes of motion intrinsically accessible to this enzyme. Here, we present the results from normal mode analysis using an elastic network model representation, which shows that the conformational mechanisms for substrate binding by NAGK strongly correlate with the intrinsic dynamics of the enzyme in the unbound form. We further analyzed the potential mechanisms of allosteric signalling within NAGK using a Markov model for network communication. Comparative analysis of the dynamics of family members strongly suggests that the low-frequency modes of motion and the associated intramolecular couplings that establish signal transduction are highly conserved among family members, in support of the paradigm sequence→structure→dynamics→function © 2010 Marcos et al

Mutation of Archaeal Isopentenyl Phosphate Kinase Highlights Mechanism and Guides Phosphorylation of Additional Isoprenoid Monophosphates

I sopentenyl diphosphate (IPP) and its isomeric part-ner dimethylallyl diphosphate (DMAPP) are precur-sors for a diverse collection of primary and second-ary isoprenoid metabolites in all organisms. Following its formation, successive units of IPP are used together either with DMAPP, formed by the action of types I or II IPP isomerases, or with the IPP extended isoprenoid diphosphate chain, to biosynthesize C10, C15, or C20 oligoprenyl diphosphates known as geranyl diphos-phate (GPP), farnesyl diphosphate (FPP), and gera-nylgeranyl diphosphate (GGPP), respectively, as well as larger isoprenoid diphosphates. In plants and some mi-croorganisms, GPP, FPP, and GGPP also serve as start-ingmaterials for the biosynthesis of a large class of spe-cialized and often cyclic terpene hydrocarbons (1). FPP is the most ubiquitous of the three isoprenoid diphos-phate building blocks, as it resides at the juncture of bi

Structural Features Underlying the Multisite Phosphorylation of the A Domain of the NF-AT4 Transcription Factor by Protein Kinase CK1 †

ABSTRACT: The phosphorylation and dephosphorylation of the NF-AT family of transcription factors play a key role in the activation of T lymphocytes and in the control of the immune response. The mechanistic aspects of NF-AT4 phosphorylation by protein kinase CK1 have been studied in this work with the aid of a series of 27 peptides, reproducing with suitable modifications the regions of NF-AT4 that have been reported to be phosphorylated by this protein kinase. The largest parent peptide, representing the three regions A, Z, and L spanning amino acids 173-218, is readily phosphorylated by CK1 at seryl residues belonging to the A2 segment, none of which fulfill the canonical consensus sequence for CK1. An acidic cluster of amino acids in the linker region between domains A and Z is essential for high-efficiency phosphorylation of the A2 domain, as shown by the increase in K m caused by a deletion of the linker region or a substitution of the acidic residues with glycines. Individual substitutions with alanine of each of the five serines in the A2 domain (S-177, S-180, S-181, S-184, and S-186) reduce the phosphorylation rate, the most detrimental effect being caused by Ser177 substitution which results in a 10-fold drop in V max . On the contrary, the replacement of Ser177 with phosphoserine triggers a hierarchical effect with a dramatic improvement in phosphorylation efficiency, which no longer depends on the linker region for optimal efficiency. These data are consistent with a two-phase phosphorylation mechanism of NF-AT4 by CK1, initiated by the linker region which provides a functional docking site for CK1 and allows the unorthodox phosphorylation of Ser177; once achieved, this phosphoserine residue primes the phosphorylation of other downstream seryl residues, according to a hierarchical mechanism typically exploited by CK1. The large number of protein kinases in eukaryotes, with over 800 genes found in the human genome (1), raises multiple questions as to the function and specificity of these important enzymes. In recent years, several laboratories, including ours, have approached the study of the substrate specificity of protein kinases. These studies have concentrated on the analysis of the amino acid sequences surrounding the immediate vicinity of the sites that are phosphorylated in vivo and in vitro by specific kinases and on the preparation of synthetic peptides that contain these sequences and serve as substrates for these particular enzymes (2-5). These studies have been very useful in determining the consensus sequence recognized preferentially by the active center of these kinases and in predicting the domains of new proteins that are probably phosphorylated by these enzymes. In addition, this approach has allowed us to design several peptides that are highly specific for kinases and that can be employed in assaying for the activity of these kinases in crude extracts of cells and tissues (e.g., refs 5-7). The studies with short peptides, however, demonstrated that these model molecules are sometimes less efficient than the true physiological substrates. In addition, several sequences that contain the defined consensus for phosphorylation by these kinases are not phosphorylated in the native proteins. Conversely, atypical sites that are not acted upon in model peptides serve as good substrates within the context of whole proteins (5). These results clearly indicate that the phosphorylation of proteins by protein kinases involves recognition and interactions that go beyond the immediate vicinity of the acceptor serines or threonines in the substrates. The recent discovery that several protein kinases recognize "docking sites" which are distant from the phosphorylatable residues in their protein substrates constitutes an important step toward the understanding of some of the complexities that provide specificity in kinase-protein substrate interactions (8)

Impact of anthropogenic noise on the survival and development of meagre (Argyrosomus regius) early life stages

The growth of human populations has been driving an unprecedent and widespread increase in marine traffic, posing a real threat to marine biodiversity. Even though we are now aware of the negative effects of shipping noise exposure on fish, information about the impact on their early life stages continues to lack. Meagre (Argyrosomus regius) is a vocal fish that uses estuaries with high levels of anthropogenic noise pollution as both breeding areas and nurseries. Here, the effects of boat noise exposure on the development and survival of meagre larvae were studied. Embryos and larvae were exposed to either noise (boat noise playback) or control treatments (coils producing a similar electric field to the speakers) and hatching rate, survival rate, morphometric traits and stress-related biomarkers, at hatching and at 2 days-post-hatching (dph) were analyzed. Results showed no conclusive effects of the impact of boat noise playback, even though there was an increased lipid droplet consumption and a decrease in body depth at 2dph larvae under this stressor. The assessment of oxidative stress and energy metabolism-related biomarkers at hatching showed a marginal decrease in superoxide dismutase (SOD) activity and no changes in DNA damage or electron transport system activity (ETS), although it cannot be disregarded that those effects could only be visible at later stages of larval development. Whether these morphological and developmental results have implications in later stages remains to be investigated. Further studies with longer exposure and wild meagre could help deepen this knowledge and provide a better understanding of how anthropogenic noise can impact meagre early stagesFundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

Gender and respiratory factors associated with dyspnea in chronic obstructive pulmonary disease

RATIONALE: We had shown that COPD women expressed more dyspnea than men for the same degree of airway obstruction. OBJECTIVES: Evaluate gender differences in respiratory factors associated with dyspnea in COPD patients. METHODS: In a FEV(1 )% matched population of 100 men and women with COPD we measured: age, MMRC, FEV(1), FVC, TLC, IC/TLC, PaO(2), PaCO(2), D(LCO), P(imax), P(0.1), Ti/Ttot, BMI, ffmi, 6MWD and VAS scale before and after the test, the Charlson score and the SGRQ. We estimated the association between these parameters and MMRC scores. Multivariate analysis determined the independent strength of those associations. RESULTS: MMRC correlated with: BMI (men:-0.29, p = 0.04; women:-0.28, p = 0.05), ffmi (men:-0.39, p = 0.01), FEV(1 )% (men:-0.64, p < 0.001; women:-0.29, p = 0.04), FVC % (men:-0.45, p = 0.001; women:-0.33, p = 0.02), IC/TLC (men:-0.52, p < 0.001; women: -0.27, p = 0.05), PaO(2 )(men:-0.59, p < 0.001), PaCO(2 )(men:0.27, p = 0.05), D(LCO )(men:-0.54, p < 0.001), P(0.1)/P(imax )(men:0.46, p = 0.002; women:0.47, p = 0.005), dyspnea measured with the Visual Analog Scale before (men:0.37, p = 0.04; women:0.52, p = 0.004) and after 6MWD (men:0.52, p = 0.002; women:0.48, p = 0.004) and SGRQ total (men:0.50, p < 0.001; women:0.59, p < 0.001). Regression analysis showed that P(0.1)/P(imax )in women (r(2 )= 0.30) and BMI, DL(CO), PaO(2 )and P(0.1)/P(imax )in men (r(2 )= 0.81) were the strongest predictors of MMRC scores. CONCLUSION: In mild to severe COPD patients attending a pulmonary clinic, P(0.1)/P(imax )was the unique predictor of MMRC scores only in women. Respiratory factors explain most of the variations of MMRC scores in men but not in women. Factors other than the respiratory ones should be included in the evaluation of dyspnea in women with COPD

XIPE: the X-ray Imaging Polarimetry Explorer

X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017 but not selected. XIPE is composed of two out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD) filled with a He-DME mixture at their focus and two additional GPDs filled with pressurized Ar-DME facing the sun. The Minimum Detectable Polarization is 14 % at 1 mCrab in 10E5 s (2-10 keV) and 0.6 % for an X10 class flare. The Half Energy Width, measured at PANTER X-ray test facility (MPE, Germany) with JET-X optics is 24 arcsec. XIPE takes advantage of a low-earth equatorial orbit with Malindi as down-link station and of a Mission Operation Center (MOC) at INPE (Brazil).Comment: 49 pages, 14 figures, 6 tables. Paper published in Experimental Astronomy http://link.springer.com/journal/1068

Regional Genetic Structure in the Aquatic Macrophyte Ruppia cirrhosa Suggests Dispersal by Waterbirds

The evolutionary history of the genus Ruppia has been shaped by hybridization, polyploidisation and vicariance that have resulted in a problematic taxonomy. Recent studies provided insight into species circumscription, organelle takeover by hybridization, and revealed the importance of verifying species identification to avoid distorting effects of mixing different species, when estimating population connectivity. In the present study, we use microsatellite markers to determine population diversity and connectivity patterns in Ruppia cirrhosa including two spatial scales: (1) from the Atlantic Iberian coastline in Portugal to the Siculo-Tunisian Strait in Sicily and (2) within the Iberian Peninsula comprising the Atlantic-Mediterranean transition. The higher diversity in the Mediterranean Sea suggests that populations have had longer persistence there, suggesting a possible origin and/or refugial area for the species. The high genotypic diversities highlight the importance of sexual reproduction for survival and maintenance of populations. Results revealed a regional population structure matching a continent-island model, with strong genetic isolation and low gene flow between populations. This population structure could be maintained by waterbirds, acting as occasional dispersal vectors. This information elucidates ecological strategies of brackish plant species in coastal lagoons, suggesting mechanisms used by this species to colonize new isolated habitats and dominate brackish aquatic macrophyte systems, yet maintaining strong genetic structure suggestive of very low dispersal.Fundacao para a Cincia e Tecnologia (FCT, Portugal) [PTDC/MAR/119363/2010, BIODIVERSA/0004/2015, UID/Multi/04326/2013]Pew FoundationSENECA FoundationMurcia Government, Spain [11881/PI/09]FCT Investigator Programme-Career Development [IF/00998/2014]Spanish Ministry of Education [AP2008-01209]European Community [00399/2012]info:eu-repo/semantics/publishedVersio

Nursing Diagnosis Risk for falls: prevalence and clinical profile of hospitalized patients

Objectives: to identify the prevalence of the Nursing Diagnosis (ND) Risk for falls in the hospitalizations of adult patients in clinical and surgical units, to characterize the clinical profile and to identify the risk factors of the patients with this ND. Method: a cross-sectional study with 174 patients. The data was collected from the computerized nursing care prescriptions system and on-line hospital records, and analyzed statistically. Results: the prevalence of the ND Risk for falls was 4%. The patients’ profile indicated older adults, males (57%), those hospitalized in the clinical units (63.2%), with a median length of hospitalization of 20 (10-24) days, with neurological illnesses (26%), cardio-vascular illnesses (74.1%) and various co-morbidities (3±1.8). The prevalent risk factors were neurological alterations (43.1%), impaired mobility (35.6%) and extremes of age (10.3%). Conclusion: the findings contributed to evidencing the profile of the patients with a risk of falling hospitalized in clinical and surgical wards, which favors the planning of interventions for preventing this adverse event