21 research outputs found

    Meta-analysis of marital dissolution and mortality: Reevaluating the intersection of gender and age

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    The study of marital dissolution (i.e. divorce and separation) and mortality has long been a major topic of interest for social scientists. We conducted meta-analyses and meta-regressions on 625 mortality risk estimates from 104 studies, published between 1955 and 2011, covering 24 countries, and providing data on more than 600 million persons. The mean hazard ratio (HR) for mortality in our meta-analysis was 1.30 (95% confidence interval [CI], 1.23–1.37) among HRs adjusted for age and additional covariates. The mean HR was higher for men (HR, 1.37; 95% CI, 1.27–1.49) than for women (HR, 1.22; 95% CI: 1.13–1.32), but the difference between men and women decreases as the mean age increases. Other significant moderators of HR magnitude included sample size; being from Western Europe, Israel, the United Kingdom and former Commonwealth nations; and statistical adjustment for general health status

    Effect of Tropomyosin on Formin-Bound Actin Filaments

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    Formins are conservative proteins with important roles in the regulation of the microfilament system in eukaryotic cells. Previous studies showed that the binding of formins to actin made the structure of actin filaments more flexible. Here, the effects of tropomyosin on formin-induced changes in actin filaments were investigated using fluorescence spectroscopic methods. The temperature dependence of the Förster-type resonance energy transfer showed that the formin-induced increase of flexibility of actin filaments was diminished by the binding of tropomyosin to actin. Fluorescence anisotropy decay measurements also revealed that the structure of flexible formin-bound actin filaments was stabilized by the binding of tropomyosin. The stabilizing effect reached its maximum when all binding sites on actin were occupied by tropomyosin. The effect of tropomyosin on actin filaments was independent of ionic strength, but became stronger as the magnesium concentration increased. Based on these observations, we propose that in cells there is a molecular mechanism in which tropomyosin binding to actin plays an important role in forming mechanically stable actin filaments, even in the case of formin-induced rapid filament assembly

    Characterization of the Biochemical Properties and Biological Function of the Formin Homology Domains of Drosophila DAAM*

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    We characterized the properties of Drosophila melanogaster DAAM-FH2 and DAAM-FH1-FH2 fragments and their interactions with actin and profilin by using various biophysical methods and in vivo experiments. The results show that although the DAAM-FH2 fragment does not have any conspicuous effect on actin assembly in vivo, in cells expressing the DAAM-FH1-FH2 fragment, a profilin-dependent increase in the formation of actin structures is observed. The trachea-specific expression of DAAM-FH1-FH2 also induces phenotypic effects, leading to the collapse of the tracheal tube and lethality in the larval stages. In vitro, both DAAM fragments catalyze actin nucleation but severely decrease both the elongation and depolymerization rate of the filaments. Profilin acts as a molecular switch in DAAM function. DAAM-FH1-FH2, remaining bound to barbed ends, drives processive assembly of profilin-actin, whereas DAAM-FH2 forms an abortive complex with barbed ends that does not support profilin-actin assembly. Both DAAM fragments also bind to the sides of the actin filaments and induce actin bundling. These observations show that the D. melanogaster DAAM formin represents an extreme class of barbed end regulators gated by profilin
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