2,067 research outputs found

    Dynamin Is Functionally Coupled to Insulin Granule Exocytosis

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    The insulin granule integral membrane protein marker phogrin-green fluorescent protein was co-localized with insulin in Min6B1 beta-cell secretory granules but did not undergo plasma membrane translocation following glucose stimulation. Surprisingly, although expression of a dominant-interfering dynamin mutant (Dyn/K44A) inhibited transferrin receptor endocytosis, it had no effect on phogringreen fluorescent protein localization in the basal or secretagogue-stimulated state. By contrast, co-expression of Dyn/K44A with human growth hormone as an insulin secretory marker resulted in a marked inhibition of human growth hormone release by glucose, KCl, and a combination of multiple secretagogues. Moreover, serial pulse depolarization stimulated an increase in cell surface capacitance that was also blocked in cells expressing Dyn/K44A. Similarly, small interference RNA-mediated knockdown of dynamin resulted in marked inhibition of glucose-stimulated insulin secretion. Together, these data suggest the presence of a selective kiss and run mechanism of insulin release. Moreover, these data indicate a coupling between endocytosis and exocytosis in the regulation of beta-cell insulin secretion

    Lipid raft microdomain compartmentalization of TC10 is required for insulin signaling and GLUT4 translocation.

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    Recent studies indicate that insulin stimulation of glucose transporter (GLUT)4 translocation requires at least two distinct insulin receptor-mediated signals: one leading to the activation of phosphatidylinositol 3 (PI-3) kinase and the other to the activation of the small GTP binding protein TC10. We now demonstrate that TC10 is processed through the secretory membrane trafficking system and localizes to caveolin-enriched lipid raft microdomains. Although insulin activated the wild-type TC10 protein and a TC10/H-Ras chimera that were targeted to lipid raft microdomains, it was unable to activate a TC10/K-Ras chimera that was directed to the nonlipid raft domains. Similarly, only the lipid raft-localized TC10/ H-Ras chimera inhibited GLUT4 translocation, whereas the TC10/K-Ras chimera showed no significant inhibitory activity. Furthermore, disruption of lipid raft microdomains by expression of a dominant-interfering caveolin 3 mutant (Cav3/DGV) inhibited the insulin stimulation of GLUT4 translocation and TC10 lipid raft localization and activation without affecting PI-3 kinase signaling. These data demonstrate that the insulin stimulation of GLUT4 translocation in adipocytes requires the spatial separation and distinct compartmentalization of the PI-3 kinase and TC10 signaling pathways

    Communication platform for disaster response

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    Reward processing in autism: a thematic series

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    This thematic series presents theoretical and empirical papers focused on understanding autism from the perspective of reward processing deficits. Although the core symptoms of autism have not traditionally been conceptualized with respect to altered reward-based processes, it is clear that brain reward circuitry plays a critical role in guiding social and nonsocial learning and behavior throughout development. Additionally, brain reward circuitry may respond to social sources of information in ways that are similar to responses to primary rewards, and recent clinical data consistently suggest abnormal behavioral and neurobiologic responses to rewards in autism. This thematic series presents empirical data and review papers that highlight the utility of considering autism from the perspective of reward processing deficits. Our hope is that this novel framework may further elucidate autism pathophysiology, with the ultimate goal of yielding novel insights with potential therapeutic implications

    The impact of emotional well-being on long-term recovery and survival in physical illness: a meta-analysis

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    This meta-analysis synthesized studies on emotional well-being as predictor of the prognosis of physical illness, while in addition evaluating the impact of putative moderators, namely constructs of well-being, health-related outcome, year of publication, follow-up time and methodological quality of the included studies. The search in reference lists and electronic databases (Medline and PsycInfo) identified 17 eligible studies examining the impact of general well-being, positive affect and life satisfaction on recovery and survival in physically ill patients. Meta-analytically combining these studies revealed a Likelihood Ratio of 1.14, indicating a small but significant effect. Higher levels of emotional well-being are beneficial for recovery and survival in physically ill patients. The findings show that emotional well-being predicts long-term prognosis of physical illness. This suggests that enhancement of emotional well-being may improve the prognosis of physical illness, which should be investigated by future research

    Unordered Business Processes, Sustainability and Green IS

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    Green Information Systems (Green IS) provides a socio-technical perspective on the diverse complex phenomena of organisational sustainability. The Cynefin sense-making framework is eminently suitable for making sense of dynamic, complex phenomena and for guiding sensible decisions on how to meet the challenges they present. The Cynefin framework is described here and illustrated in terms of both ordered and unordered business processes. It is the unordered that are the least understood; but they are the most critical when it comes to sustainability. While order may be appropriate in the short term, sustainability issues also demand a more challenging long-term perspective. Just how rapidly and unpredictably business processes can change is well known in the field of IS which understands the revolutionary nature of new digital technologies. This chapter explores ways to manage sustainably in the face of such uncertainty through an appreciation of unordered complexity
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