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Computational Biology Group, Department of Clinical Laboratory Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Medical School, 7925 Observatory, Cape Town, South Africa.
Despite ever-increasing amounts of sequence and functional genomics data, there is still a deficiency of functional annotation for many newly sequenced proteins. For Mycobacterium tuberculosis (MTB), more than half of its genome is still uncharacterized, which hampers the search for new drug targets within the bacterial pathogen and limits our understanding of its pathogenicity. As for many other genomes, the annotations of proteins in the MTB proteome were generally inferred from sequence homology, which is effective but its applicability has limitations. We have carried out large-scale biological data integration to produce an MTB protein functional interaction network. Protein functional relationships were extracted from the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and additional functional interactions from microarray, sequence and protein signature data. The confidence level of protein relationships in the additional functional interaction data was evaluated using a dynamic data-driven scoring system. This functional network has been used to predict functions of uncharacterized proteins using Gene Ontology (GO) terms, and the semantic similarity between these terms measured using a state-of-the-art GO similarity metric. To achieve better trade-off between improvement of quality, genomic coverage and scalability, this prediction is done by observing the key principles driving the biological organization of the functional network. This study yields a new functionally characterized MTB strain CDC1551 proteome, consisting of 3804 and 3698 proteins out of 4195 with annotations in terms of the biological process and molecular function ontologies, respectively. These data can contribute to research into the Development of effective anti-tubercular drugs with novel biological mechanisms of action.
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IFOM Foundation - The FIRC Institute of Molecular Oncology Foundation via Adamello 16, 20139 Milan, Italy SEMM - European School of Molecular Medicine via Adamello 16, 20139 Milan, Italy Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche, Via Abbiategrasso 207, 27100 Pavia, Italy.
It is generally accepted that the permanent arrest of cell division known as cellular senescence contributes to aging by an antagonistic pleiotropy mechanism: cellular senescence would act beneficially early in life by suppressing cancer, but detrimentally later on by causing frailty and, paradoxically, cancer. In this review, we show that there is room to rethink this common view. We propose a critical appraisal of the arguments commonly brought in support of it, and we qualitatively analyse published results that are of relevance to understand whether or not cellular senescence-associated genes really act in an antagonistic-pleiotropic manner in humans.
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[My paper] Alice Lee, Una Browne
Department of Speech and Hearing Sciences, University College Cork , Cork , Ireland.
The aim was to establish normative nasalance values for Irish English-speaking adults. Thirty men and 30 women with normal resonance read aloud 16 sentences from the Irish nasality assessment protocol, the Zoo passage, and the Rainbow passage. The speech samples were recorded using the Nasometer II 6400. Results of a mixed between-within subjects ANOVA indicated no significant gender effect on nasalance scores. The speakers showed significantly higher nasalance scores for high-pressure consonant sentences than low-pressure consonant sentences, and for the Rainbow passage than total test sentences. There was no significant difference between high-pressure consonant sentences and the Zoo passage. Compared to previous studies, the Irish young adults had lower nasalance scores than Irish children and than young adults with North American dialects.
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Jonathan C. Kagan, Ph.D. Assistant Professor of Pediatrics Harvard Medical School Staff Scientist, Division of Gastroenterology Children's Hospital Boston 300 Longwood Ave, Enders 649 Boston, MA 02115 617-919-4852 Akiko Iwasaki, Ph.D. Department of Immunobiology Yale University School of Medicine 300 Cedar Street, TAC S655B, New Haven, CT 06520 USA Email: akiko.iwasaki@yale.edu Phone (203) 785-2919 FAX (203) 785-4972.
The means by which phagocytosis and antimicrobial defense mechanisms are linked have expanded greatly in recent years. It is now clear that the process of phagocytosis does more than just degrade internalized microbes, but also helps coordinate the actions of the innate and adaptive immune system. This review will discuss the means by which Toll-like Receptor signaling pathways are coordinated around the processes of phagocytosis, phagosome trafficking and autophagy and how these signaling pathways influence T-cell mediated immunity. In this regard, we propose that at the subcellular level, phagosomes represent the smallest definable unit that links innate and adaptive immunity.
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Robert W. Franz Cancer Center, Earle A. Chiles Research Institute, Providence Portland Medical Center, Portland OR 97213 USA. Department of Microbiology and Immunology, University of California, San Francisco, CA 94143, USA.
The treatment of high-grade tumors must consider a tumor environment dominated by cells that support cancer growth. In addition to directing angiogenesis and invasion, alternatively activated macrophages in the tumor provide protection from adaptive immunity and permit tumor growth. Agonist antibodies to the TNF receptor family member OX40 are an effective therapy for cancer in a range of murine models; however, as with many immune therapies, αOX40 therapy is less effective as the tumor grows and develops an immune suppressive environment. We demonstrate that αOX40 directly activates T cells and that this T cell activation alters macrophage differentiation in the tumor environment. We demonstrate that macrophages in the tumor limit the efficacy of αOX40 therapy, and that combining αOX40 therapy with inhibitors of arginase significantly enhances survival of tumor-bearing mice. These data demonstrate that macrophages in the tumor environment limit the effectiveness of OX40-based immunotherapy, and combination therapies that target both the cell-mediated immune response and the suppressive tumor environment will be required for translation of effective immunotherapies to patients with established tumors. © 2012 The Authors. Immunology © 2012 Blackwell Publishing Ltd, Immunology.
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ABSTRACT: BACKGROUND: An important question in the analysis of biochemical data is that of identifying subsets of molecular variables that may jointly influence a biological response. Statistical variable selection methods have been widely used for this purpose. In many settings, it may be important to incorporate ancillary biological information concerning the variables of interest. Pathway and network maps are one example of a source of such information. However, although ancillary information is increasingly available, it is not always clear how it should be used nor how it should be weighted in relation to primary data. RESULTS: We put forward an approach in which biological knowledge is incorporated using informative prior distributions over variable subsets, with prior information selected and weighted in an automated, objective manner using an empirical Bayes formulation. We employ continuous, linear models with interaction terms and exploit biochemically-motivated sparsity constraints to permit exact inference. We show an example of priors for pathway- and network-based information and illustrate our proposed method on both synthetic response data and by an application to cancer drug response data. Comparisons are also made to alternative Bayesian and frequentist penalised-likelihood methods for incorporating network-based information. CONCLUSIONS: The empirical Bayes method proposed here can aid prior elicitation for Bayesian variable selection studies and help to guard against mis-specification of priors. Empirical Bayes, together with the proposed pathway-based priors, results in an approach with a competitive variable selection performance. In addition, the overall procedure is fast, deterministic, and has very few user-set parameters, yet is capable of capturing interplay between molecular players. The approach presented is general and readily applicable in any setting with multiple sources of biological prior knowledge.
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Center for Neural Circuits and Behavior, Division of Biology, and Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093, USA.
The lateral habenula (LHb) has recently been identified as a key regulator of the reward system by driving inhibition onto dopaminergic neurons. However, the nature and potential modulation of the major input to the LHb originating from the basal ganglia are poorly understood. Although the output of the basal ganglia is thought to be primarily inhibitory, here we show that transmission from the basal ganglia to the LHb is excitatory, glutamatergic, and suppressed by serotonin. Behaviorally, activation of this pathway is aversive, consistent with its role as an "antireward" signal. Our demonstration of an excitatory projection from the basal ganglia to the LHb explains how LHb-projecting basal ganglia neurons can have similar encoding properties as LHb neurons themselves. Our results also provide a link between antireward excitatory synapses and serotonin, a neuromodulator implicated in depression.
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Massachusetts General Hospital Cancer Center and Department of Medicine, Harvard Medical School, 13(th) Street, Charlestown, MA 02129, USA.
In the current issue of Molecular Cell, Herranz et al.(2012) demonstrate that LOXL2 deaminates trimethylated histone 3 lysine 4 (H3K4me3), which uncovers a new chromatin modification and a new enzymatic mechanism with the potential to regulate additional lysine residues.
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MRC/Wellcome Trust Behavioural and Clinical Neuroscience Institute (BCNI), Department of Experimental Psychology, University of Cambridge, Cambridge, UK.
BACKGROUND: Obsessive-compulsive disorder (OCD) has been associated with response inhibition deficits under motivationally neutral contingencies. We examined response inhibition performance in the presence of reward and punishment. We further investigated whether the hypothesized difficulties in flexibly updating behaviour based on external feedback in OCD would also lead to a reduced ability to adjust to changes in the reward and punishment contingencies.MethodParticipants completed a go/no-go task that used punishments or rewards to promote response activation or suppression. The task was administered to OCD patients free of current Axis-I co-morbidities including major depression (n=20) and a group of healthy controls (n=32). RESULTS: Compared with controls, patients with OCD had increased commission errors in punishment conditions, and failed to slow down immediately after receiving punishment. The punishment-induced increase in commission errors correlated with self-report measures of OCD symptom severity. Additionally, patients did not differ from controls in adapting their overall response style to the changes in task contingencies. CONCLUSIONS: Individuals with OCD showed reduced response control selectively under punishment conditions, manifesting in an impulsive response style that was related to their current symptom severity. This stresses failures of cognitive control in OCD, particularly under negative motivational contingencies.
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Translational Gastroenterology Unit, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK.
Gut-associated lymphoid tissue (GALT) is a sensor region for luminal content and plays an important role in lymphoid maturation, activation and differentiation. It comprises isolated and aggregated lymphoid follicles, cryptopatches (CPs) and tertiary lymphoid tissue. Innate lymphoid cells (ILCs) play a central role within GALT. Prenatal GALT development is dependent on ILC lymphoid-inducer function. Postnatally, these cells rapidly respond to commensal and pathogenic intestinal bacteria, parasites and food components by polarized cytokine production [such as interleukin (IL)-22, IL-17 or IL-13] and further contribute to GALT formation and function. Here, we discuss how ILCs shape lymphoid intestinal microenvironments and act as amplifier cells for innate and adaptive immune responses.
Cell. 2012 May 9;:   22579045 
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Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Department of Informatics, Technische Universität München, 85748 Garching, Germany.
We show that amino acid covariation in proteins, extracted from the evolutionary sequence record, can be used to fold transmembrane proteins. We use this technique to predict previously unknown 3D structures for 11 transmembrane proteins (with up to 14 helices) from their sequences alone. The prediction method (EVfold_membrane) applies a maximum entropy approach to infer evolutionary covariation in pairs of sequence positions within a protein family and then generates all-atom models with the derived pairwise distance constraints. We benchmark the approach with blinded de novo computation of known transmembrane protein structures from 23 families, demonstrating unprecedented accuracy of the method for large transmembrane proteins. We show how the method can predict oligomerization, functional sites, and conformational changes in transmembrane proteins. With the rapid rise in large-scale sequencing, more accurate and more comprehensive information on evolutionary constraints can be decoded from genetic variation, greatly expanding the repertoire of transmembrane proteins amenable to modeling by this method.
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Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
The epidermal growth factor receptor (EGFR) is normally activated by ligand-induced dimerization. Oncogenic mutations in EGFR promote activation in a largely ligand-independent manner. Shan et al. uncover a partially disordered state of EGFR kinase, providing evidence that oncogenic mutations counteract this intrinsic structural instability to promote dimerization and aberrant activation.
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Wellcome Trust Centre for Neuroimaging, University College of London, United Kingdom; Laboratory for Social and Neural Systems Research, Dept. of Economics, University of Zurich, Switzerland; Brain and Spine Institute, Paris, France.
Dynamic Causal Modelling (DCM) was introduced to study the effective connectivity among brain regions using neuroimaging data. Until recently, DCM relied on deterministic models of distributed neuronal responses to external perturbation (e.g., sensory stimulation or task demands). However, accounting for stochastic fluctuations in neuronal activity and their interaction with task-specific processes may be of particular importance for studying state-dependent interactions. Furthermore, allowing for random neuronal fluctuations may render DCM more robust to model misspecification and finesse problems with network identification. In this article, we examine stochastic dynamic causal models (sDCM) in relation to their deterministic counterparts (dDCM) and highlight questions that can only be addressed with sDCM. We also compare the network identification performance of deterministic and stochastic DCM, using Monte Carlo simulations and an empirical case study of absence epilepsy. For example, our results demonstrate that stochastic DCM can exploit the modelling of neural noise to discriminate between direct and mediated connections. We conclude with a discussion of the added value and limitations of sDCM, in relation to its deterministic homologue.
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Section of Forest Genetics, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany; Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany.
Cenococcum geophilum is a widely distributed ectomycorrhizal fungus potentially playing a significant role in resistance and resilience mechanisms of its tree hosts exposed to drought stress. In this study, we performed a large scale protein analysis in pure cultures of C. geophilum in order to gain first global insights into the proteome assembly of this fungus. Using 1-D gel electrophoresis coupled with ESI-MS/MS, we indentified 638 unique proteins. Most of these proteins were related to the metabolic and cellular processes, and the transport machinery of cells. In a second step, we examined the influence of water deprivation on the proteome of C. geophilum pure cultures at three time points of gradually imposed drought. The results indicated that 12 proteins were differentially abundant in mycelia subjected to drought compared to controls. The induced responses in C. geophilum point towards regulation of osmotic stress, maintainance of cell integrity, and counteracting increased levels of reactive oxygen species formed during water deprivation.
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[My paper] Toby J Gibson
Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
It should not be surprising that a protein with a name like RACK1 - short for Receptor for Activated C Kinase 1 - is found in a variety of signaling complexes. Its alternative name, the splendidly unmemorable GNB2L1 - short for Guanine Nucleotide-binding protein subunit Beta-2-Like 1 - should reinforce this link to signaling complexes. There are currently over 400 publications listed in PubMed mentioning RACK1/GNB2L1 in the abstract, so it is certainly an actively studied protein with much involvement in different aspects of cell regulation is being reported. RACK1 binds to the 40S ribosomal subunit, suggesting it links cell regulation and translation. It is also a target of intracellular parasites. And yet does this protein have the profile that it should? And why are there two kinds of RACK1 researcher who don't seem to communicate well?
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The Beatson Institute for Cancer Research, Glasgow, UK.
Tumour-derived mutant p53 proteins promote invasion, in part, by enhancing Rab coupling protein (RCP)-dependent receptor recycling. Here we identified MET as an RCP-binding protein and showed that mutant p53 promoted MET recycling. Mutant p53-expressing cells were more sensitive to hepatocyte growth factor, the ligand for MET, leading to enhanced MET signalling, invasion and cell scattering that was dependent on both MET and RCP. In cells expressing the p53 family member TAp63, inhibition of TAp63 also lead to cell scattering and MET-dependent invasion. However, in cells that express very low levels of TAp63, the ability of mutant p53 to promote MET-dependent cell scattering was independent of TAp63. Taken together, our data show that mutant p53 can enhance MET signalling to promote cell scattering and invasion through both TAp63-dependent and -independent mechanisms. MET has a predominant role in metastatic progression and the identification of mechanisms through which mutations in p53 can drive MET signalling may help to identify and direct therapy.Oncogene advance online publication, 14 May 2012; doi:10.1038/onc.2012.148.
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Departments of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Cdt1, a protein critical for replication origin licensing in G1 phase, is degraded during S phase but re-accumulates in G2 phase. We now demonstrate that human Cdt1 has a separable essential mitotic function. Cdt1 localizes to kinetochores during mitosis through interaction with the Hec1 component of the Ndc80 complex. G2-specific depletion of Cdt1 arrests cells in late prometaphase owing to abnormally unstable kinetochore-microtubule (kMT) attachments and Mad1-dependent spindle-assembly-checkpoint activity. Cdt1 binds a unique loop extending from the rod domain of Hec1 that we show is also required for kMT attachment. Mutation of the loop domain prevents Cdt1 kinetochore localization and arrests cells in prometaphase. Super-resolution fluorescence microscopy indicates that Cdt1 binding to the Hec1 loop domain promotes a microtubule-dependent conformational change in the Ndc80 complex in vivo. These results support the conclusion that Cdt1 binding to Hec1 is essential for an extended Ndc80 configuration and stable kMT attachment.
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[My paper] M Stenroos, J Sarvas
Department of Biomedical Engineering and Computational Science, Aalto University, PO Box, FI-00076 Aalto, Finland. MRC Cognition and Brain Sciences Unit, 15 Chaucer Road, Cambridge CB2 7EF, UK.
Electro- and magnetoencephalography (EEG and MEG) are non-invasive modalities for studying the electrical activity of the brain by measuring voltages on the scalp and magnetic fields outside the head. In the forward problem of EEG and MEG, the relationship between the neural sources and resulting signals is characterized using electromagnetic field theory. This forward problem is commonly solved with the boundary-element method (BEM). The EEG forward problem is numerically challenging due to the low relative conductivity of the skull. In this work, we revise the isolated source approach (ISA) that enables the accurate, computationally efficient BEM solution of this problem. The ISA is formulated for generic basis and weight functions that enable the use of Galerkin weighting. The implementation of the ISA-formulated linear Galerkin BEM (LGISA) is first verified in spherical geometry. Then, the LGISA is compared with conventional Galerkin and symmetric BEM approaches in a realistic 3-shell EEG/MEG model. The results show that the LGISA is a state-of-the-art method for EEG/MEG forward modeling: the ISA formulation increases the accuracy and decreases the computational load. Contrary to some earlier studies, the results show that the ISA increases the accuracy also in the computation of magnetic fields.
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Medical Research Council Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom. j.ware@imperial.ac.uk.
Discriminating between rare benign and pathogenic variation is a key challenge in clinical genetics, particularly as increasing numbers of non-synonymous SNPs are identified in resequencing studies. Here, we describe an approach for the functional annotation of non-synonymous variants that identifies functionally important, disease-causing residues across protein families using multiple sequence alignment. We applied the methodology to long QT syndrome (LQT) genes, which cause sudden death, and their paralogues, which largely cause neurological disease, and accurately classified known LQT disease-causing variants (positive predictive value = 98.4%) with a better performance than established bioinformatic methods. The analysis also identified 1078 new putative disease loci, which we incorporated along with known variants into a comprehensive and freely accessible long QT resource (http://cardiodb.org/Paralogue_Annotation/), based on newly created Locus Reference Genomic sequences (http://www.lrg-sequence.org/). We propose that paralogous annotation is widely applicable for Mendelian human disease genes.
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Emory University, Division of Cardiology, 319 WMB, 1639 Pierce Dr, Atlanta, GA 30322. kgriend@emory.edu.
atherosclerosis, hypertension, cardiac hypertrophy and remodeling, angiogenesis and collateral formation, stroke, and heart failure. In this review, we discuss in detail the biochemistry of Nox enzymes expressed in the cardiovascular system (Nox1, 2, 4, and 5), their roles in cardiovascular cell biology, and their contributions to disease development.
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2012-05-17 07:50:57 © BioInfoBank Institute