17 research outputs found

    The functions of sleep

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    Multi-agent Patrolling: An Empirical Analysis of Alternative Architectures

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    Towards a more inclusive agricultural insurance program

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    Typhoons, pests and other natural calamities cause the country, particularly the agricultural sector, significant damages. For instance, Typhoons Yolanda (Haiyan) and Ompong (Mangkhut) have caused PHP 35 billion and PHP 27 billion worth of agricultural damages, respectively, based on estimates by the Department of Agriculture. Given that a third of the country's workforce depend on the agriculture sector, it is crucial that efforts are undertaken towards mitigation of the effects of these shocks and risks. One of these efforts is agricultural insurance as provided for by the Philippine Crop Insurance Corporation (PCIC). Using information from the PCIC, key informant interviews and focus group discussions with agricultural producers, and findings from earlier studies on agricultural insurance, this study examines the constraints in, opportunities, and efforts for achieving impact and inclusion of agricultural insurance programs in the Philippines

    Modification by covalent reaction or oxidation of cysteine residues in the tandem-SH2 domains of ZAP-70 and Syk can block phosphopeptide binding.

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    Zeta-chain associated protein of 70 kDa (ZAP-70) and spleen tyrosine kinase (Syk) are non-receptor tyrosine kinases that are essential for T-cell and B-cell antigen receptor signalling respectively. They are recruited, via their tandem-SH2 (Src-homology domain 2) domains, to doubly phosphorylated immunoreceptor tyrosine-based activation motifs (ITAMs) on invariant chains of immune antigen receptors. Because of their critical roles in immune signalling, ZAP-70 and Syk are targets for the development of drugs for autoimmune diseases. We show that three thiol-reactive small molecules can prevent the tandem-SH2 domains of ZAP-70 and Syk from binding to phosphorylated ITAMs. We identify a specific cysteine residue in the phosphotyrosine-binding pocket of each protein (Cys39 in ZAP-70, Cys206 in Syk) that is necessary for inhibition by two of these compounds. We also find that ITAM binding to ZAP-70 and Syk is sensitive to the presence of H2O2 and these two cysteine residues are also necessary for inhibition by H2O2. Our findings suggest a mechanism by which the reactive oxygen species generated during responses to antigen could attenuate signalling through these kinases and may also inform the development of ZAP-70 and Syk inhibitors that bind covalently to their SH2 domains

    Modification by covalent reaction or oxidation of cysteine residues in the tandem-SH2 domains of ZAP-70 and Syk can block phosphopeptide binding

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    Zeta-chain Associated Protein of 70kDa (ZAP-70) and Spleen tyrosine kinase (Syk) are non-receptor tyrosine kinases that are essential for T-cell and B-cell antigen receptor signaling, respectively. They are recruited, via their tandem-SH2 domains, to doubly-phosphorylated Immunoreceptor Tyrosine-based Activation Motifs (ITAMs) on invariant chains of immune antigen receptors. Because of their critical roles in immune signaling, ZAP-70 and Syk are targets for the development of drugs for autoimmune diseases. We show that three thiol-reactive small molecules can prevent the tandem-SH2 domains of ZAP-70 and Syk from binding to phosphorylated ITAMs. We identify a specific cysteine residue in the phosphotyrosine-binding pocket of each protein (Cys 39 in ZAP-70, Cys 206 in Syk) that is necessary for inhibition by two of these compounds. We also find that ITAM binding to ZAP-70 and Syk is sensitive to the presence of hydrogen peroxide, and these two cysteine residues are also necessary for inhibition by hydrogen peroxide. Our findings suggest a mechanism by which the generation of reactive oxygen species generated during responses to antigen could attenuate signaling through these kinases, and may also inform the development of ZAP-70 and Syk inhibitors that bind covalently to their SH2 domains
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