2,425 research outputs found

    ESCRT function in cytokinesis: location, dynamics and regulation by mitotic kinases

    Get PDF
    Mammalian cytokinesis proceeds by constriction of an actomyosin ring and furrow ingression, resulting in the formation of the midbody bridge connecting two daughter cells. At the centre of the midbody resides the Flemming body, a dense proteinaceous ring surrounding the interlocking ends of anti-parallel microtubule arrays. Abscission, the terminal step of cytokinesis, occurs near the Flemming body. A series of broad processes govern abscission: the initiation and stabilisation of the abscission zone, followed by microtubule severing and membrane scission—The latter mediated by the endosomal sorting complex required for transport (ESCRT) proteins. A key goal of cell and developmental biologists is to develop a clear understanding of the mechanisms that underpin abscission, and how the spatiotemporal coordination of these events with previous stages in cell division is accomplished. This article will focus on the function and dynamics of the ESCRT proteins in abscission and will review recent work, which has begun to explore how these complex protein assemblies are regulated by the cell cycle machinery

    A complex network of interactions between mitotic kinases, phosphatases and ESCRT proteins regulates septation and membrane trafficking in S. pombe

    Get PDF
    Cytokinesis and cell separation are critical events in the cell cycle. We show that Endosomal Sorting Complex Required for Transport (ESCRT) genes are required for cell separation in Schizosaccharomyces pombe. We identify genetic interactions between ESCRT proteins and polo and aurora kinases and Cdc14 phosphatase that manifest as impaired growth and exacerbated defects in septation, suggesting that the encoded proteins function together to control these processes. Furthermore, we observed defective endosomal sorting in mutants of plo1, ark1 and clp1, as has been reported for ESCRT mutants, consistent with a role for these kinases in the control of ESCRT function in membrane traffic. Multiple observations indicate functional interplay between polo and ESCRT components: firstly, two-hybrid in vivo interactions are reported between Plo1p and Sst4p, Vps28p, Vps25p, Vps20p and Vps32p; secondly, co-immunoprecipitation of human homologues of Vps20p, Vps32p, Vps24p and Vps2p by human Plk1; and thirdly, in vitro phosphorylation of budding yeast Vps32p and Vps20p by polo kinase. Two-hybrid analyses also identified interactions between Ark1p and Vps20p and Vps32p, and Clp1p and Vps28p. These experiments indicate a network of interactions between ESCRT proteins, plo1, ark1 and clp1 that coordinate membrane trafficking and cell separation in fission yeast

    Self-reported feeding advice by physicians for common childhood illnesses

    Get PDF
    Background: A nutritious diet is important for recovery during illnesses. Dietary advice by physicians and consumption of food by the patients are often based upon their hot and cold concepts and beliefs about various foods rather than on scientific basis.Objectives: To look at the food-advising behaviour of physicians during illnesses and to know the maternal concepts about various foods being hot or cold.Methods: A questionnaire was served to the physicians participating in a continuous medical education session held at the Aga Khan University and Hospital, asking them to write the foods they advise or restrict during different illnesses such as fever, jaundice etc. Mothers of sick children suffering from diarrhea and other illnesses were also interviewed to know their concepts about various foods.Results: Six (10%) out of sixty physicians believed in hot and cold concepts of the food. A variety of common foods were either restricted or strongly recommended by 10% to 50% of these physicians without any scientific basis, 23% physicians restricted fatty foods in jaundice, 17% physicians restricted in cough and cold. Although the interviewed mothers believed in hot-cold concepts of food but 55-63% of them were not sure what is meant by hot or cold food. In spite of that 70-80% of these mothers classified chicken, meat, egg, brinjal, masoor and mangoes are hot foods and rice, yogurt, moong, banana and orange as cold foods.Conclusion: Hot-Cold concept of food exists not only in mothers but also in physicians. Proper education regarding food intake is mandatory for both mothers and physicians to ascertain adequate intake of calories during sickness

    Clinical utility of folate-containing oral contraceptives

    Get PDF
    Folate is a generic term for a water-soluble B-complex vitamin which plays an important role in protein synthesis and metabolism and other processes related to cell multiplication and tissue growth. Pregnant and lactating women are at increased risk of folic acid deficiency because generally their dietary folate is insufficient to meet their physiological requirements and the metabolic demands of the growing fetus. The evidence pertaining to the reduction of the risk of neural tube defects (NTDs) due to folate is so compelling that supplementation with 400 μg of folic acid to all women trying to conceive until 12 weeks of pregnancy has been recommended by every relevant authority. A recent Cochrane review has also found protective effects of folate supplementation in occurrence and reoccurrence of NTDs. Despite food fortification and targeted public health campaigns promoting folic acid supplementation, 4,300,000 new cases occur each year worldwide resulting in an estimated 41,000 deaths and 2.3 million disability-adjusted life years (DALYS). This article will review the burden and risk factors of NTDS, and the role of folate in preventing NTDs. It will also describe different modes of supplementing folate and the newer evidence of the effectiveness of adding folate in oral contraceptives for raising serum and red blood cell folate levels
    • …
    corecore