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No description available.

Introduction: Persistent pulmonary hypertension of the newborn (PPHN) is associated with an elevated thromboxane to prostacyclin ratio, pulmonary artery (PA) hyperreactivity and hypersensitivity. Thromboxane receptor (TP), coupling with G-protein Gαq causes pulmonary vasoconstriction; whereas prostacyclin receptor (IP), coupling with Gαs, causes vasodilation and TP phosphorylation via adenylyl cyclase (AC)-cAMP-protein kinase A (PKA), desensitizes TP. Both TP phosphorylation and Gαq palmitoylation play major roles in regulation of signaling through the TP-Gαq complex. We hypothesized that increased Gαq palmitoylation and decreased AC activity could cause hypoxic TP hyperresponsiveness. We studied the impact of hypoxia on selected post-translational modifications of the receptor-G-protein complex, determining TP vasoconstriction: Gαq palmitoylation, TP phosphorylation and upstream AC activity. Methods: Force responses to thromboxane mimetic U46619, palmitoylation inhibition by 2-bromopalmitate (2-BP) and AC activation (forskolin) were studied by myography in hypoxic PPHN and control newborn swine pulmonary artery. Ca2+ mobilization was studied by fluorescent calcium indicators fura-2AM in pulmonary myocytes (PASMC), and fluo-4NW in HEK293 cells. Effects of hypoxia on Gαq palmitoylation were studied by metabolic labeling. Gαq cysteines and TP serines were mutated to determine sites of post-translational modifications. Protein expression and receptor-G-protein coupling were studied by Western blot and co-immunoprecipitation. PKA activity was assayed; and AC activity quantified. Results: Hypoxia increases Gαq palmitoylation, without increasing total palmitate uptake. Palmitoylation inhibition decreases U46619-stimulated force generation as well as Ca2+ mobilization in PPHN PA rings and hypoxic PASMC. Mutation of palmitoylable cysteine and palmitoylation inhibition proportionately decrease U46619-mediated Ca2+ mobilization in HEK293 cells. TP serine phosphorylation is decreased by hypoxia due to decreased PKA activity; this causes TP hypersensitivity and hyper-reactivity. Serine 324 of TPα is the target of PKA-mediated desensitization. AC activator-induced relaxation is reduced in PPHN PA. Basal and receptor-stimulated AC activity are decreased in hypoxic PASMC. Decreased AC activity is not due to decreased AC expression, ATP availability nor increased Gαi activation. Conclusion: Increased Gαq palmitoylation plays a role in TPα hyper-responsiveness in hypoxic PPHN. Hypoxia also reduces responses to agents acting through AC, unleashing TP-mediated vasoconstriction. Reactivation of pulmonary AC might be useful therapeutically to promote vasodilation and TP desensitization. / October 2016

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La protéine Tax du virus HTLV-1 a les propriétés d'un oncogène viral et joue un rôle important dans l'induction de la transformation cellulaire menant à l'ATL. L'activité oncogène de Tax résulte d'effets pléiotropes sur divers mécanismes cellulaires y compris l'activation de l'expression de gènes cellulaires spécifiques par la voie NF-B et la dérégulation de la progression du cycle cellulaire. Dans ce travail, nous avons mis en évidence que Tax est une protéine hautement modifiée dans diverses lignées cellulaires y compris dans les lymphocytes T transformés par HTLV-1. L'ensemble des modifications post-traductionnelles de Tax forment une suite hiérarchisée qui contrôlent la localisation intracellulaire de Tax, sa capacité d'activer les kinases IKK et la voie de signalisation des facteurs NF-B et sa capacité d'induire un arrêt dans la progression de la mitose. En effet, la phosphorylation de Tax contrôle son ubiquitination et son passage dans le noyau où elle est sumoylée et acétylée. L’ubiquitination et la sumoylation de Tax agissent de manière concertée pour permettre l’activation de l’expression des gènes par la voie NF-B tandis que son acétylation permet de lever le blocage induit en fin de mitose. Les effets exercés par les modifications post-traductionnelles sur les fonctions oncogènes de la protéine Tax suggèrent que ces modifications pourraient être des cibles thérapeutiques pour le développement de traitements contre l'ATL.

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ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The Range Commanders Council (RCC) Inter-Range Instrumentation Group (IRIG) 106 Chapter 10 (CH 10) Solid State recording standard has made the possibility of large scale interoperability between ranges, test and operational communities, and maintenance a reality. The standard allows for software and hardware playback/analysis tools to be created that will work seamlessly with any IRIG-106 CH 10 compliant recorder. Incorporation of a standard also allows the same recorder to record Video, Audio as well as data from MIL-STD-1553 busses and instrumentation data (PCM, UART, etc.). The IRIG-106 CH 10 standard provides enormous benefits for its users, but without a fully compliant IRIG-106 CH 10 recorder, these benefits cannot be realized.

The recent emergence of the field of proteomics has been driven by advances in mass spectrometry methods and instrumentation. Due to the large amount of data generated, success at peptide and protein identification is contingent on reliable software algorithms. The software programs in use at the time the work in this dissertation was carried out were well suited to the task of identifying unmodified peptides and proteins in complex mixtures. However, the existing programs were not able to reliably identify protein modifications, especially unpredicted modifications. This dissertation describes the development of two novel software algorithms that can be used to screen LC-MS-MS data files, and identify MS-MS spectra that correspond to peptides with either predicted or unpredicted modifications. The first program, SALSA, is highly flexible and uses user defined search criteria to screen data files for spectra the exhibit fragmentation patterns diagnostic of specific modifications or peptide sequences. SALSA facilitates exhaustive searches, but requires user expertise to both generate search criteria and to validate matched spectra. The second program, P-Mod, provides automated searches for spectra corresponding to peptides in a search list. P-Mod is able to identify spectra derived from either modified or unmodified peptides. All sequence-to-spectrum matches reported in the P-Mod output are assigned statistical confidence levels derived using extreme value statistics.