Search results for "cytokinesis"
showing 10 items of 27 documents
Roles for ELMOD2 and Rootletin in ciliogenesis.
2021
AbstractELMOD2 is a GTPase activating protein (GAP) with uniquely broad specificity for ARF family GTPases. We previously showed that it acts with ARL2 in mitochondrial fusion and microtubule stability and with ARF6 during cytokinesis. Mouse embryonic fibroblasts deleted for ELMOD2 also displayed changes in cilia related processes including increased ciliation, multiciliation, ciliary morphology, ciliary signaling, centrin accumulation inside cilia, and loss of rootlets at centrosomes with loss of centrosome cohesion. Increasing ARL2 activity or overexpressing Rootletin reversed these defects, revealing close functional links between the three proteins. This was further supported by the fin…
Abnormal mitotic spindle assembly and cytokinesis induced by D-Limonene in cultured mammalian cells
2013
D-Limonene is found widely in citrus and many other plant species; it is a major constituent of many essential oils and is used as a solvent for commercial purposes. With the discovery of its chemotherapeutic properties against cancer, it is important to investigate the biological effects of the exposure to D-Limonene and elucidate its, as yet unknown, mechanism of action. We reported here that D-Limonene is toxic in V79 Chinese hamster cells in a dose-dependent manner. Moreover, to determine the cellular target of D-Limonene, we performed morphological observations and immunocytochemical analysis and we showed that this drug has a direct effect on dividing cells preventing assembly of mito…
Regulation of cytokinesis and its clinical significance.
2015
Dysregulation of the cell cycle leads to polyploid cells, which are classified into mononuclear or binuclear polyploid cells depending on the number of nuclei. Polyploidy is common in plants and in animals. Physiologically, polyploidy and binucleation are differentiation markers and also features of the aging process. In fact, although they provide multiple copies of genes required for survival, a negative correlation between growth capacity and polyploidy has been reported, and thus, suppression or reversal of this phenomenon may be a growth advantage. On the other hand, unscheduled polyploidization may cause genomic instability that might lead to neoplastic aneuploidy. The aim of this rev…
Hsp70 localizes differently from chaperone Hsc70 in mouse mesoangioblasts under physiological growth conditions
2008
Mouse A6 mesoangioblasts express Hsp70 even in the absence of cellular stress. Its expression and its intracellular localization were investigated under normal growth conditions and under hyperthermic stress. Immunofluorescence assays indicated that without any stress a fraction of Hsp70 co-localized with actin microfilaments, in the cell cortex and in the contractile ring of dividing cells, while the Hsc70 chaperone did not. Hsp70 immunoprecipitation assays confirmed that a portion of Hsp70 binds actin. Immunoblot assays showed that both proteins were present in the nucleus. After heat treatment Hsp70 and actin continued to co-localize in the leading edge of A6 cells but not on microfilame…
Identification and characterization of PlAlix, the Alix homologue from the Mediterranean sea urchin Paracentrotus lividus.
2013
The sea urchin provides a relatively simple and tractable system for analyzing the early stages of embryo development. Here, we use the sea urchin species, Paracentrotus lividus, to investigate the role of Alix in key stages of embryogenesis, namely the egg fertilization and the first cleavage division. Alix is a multifunctional protein involved in different cellular processes including endocytic membrane trafficking, filamentous (F)-actin remodeling, and cytokinesis. Alix homologues have been identified in different metazoans; in these organisms, Alix is involved in oogenesis and in determination/differentiation events during embryo development. Herein, we describe the identification of th…
Oxidative stress triggers cytokinesis failure in hepatocytes upon isolation
2015
Primary hepatocytes are highly differentiated cells and proliferatively quiescent. However, the stress produced during liver digestion seems to activate cell cycle entry by proliferative/dedifferentiation programs that still remain unclear. The aim of this work was to assess whether the oxidative stress associated with hepatocyte isolation affects cell cycle and particularly cytokinesis, the final step of mitosis. Hepatocytes were isolated from C57BL/6 mice by collagenase perfusion in the absence and presence of N-acetyl cysteine (NAC). Polyploidy, cell cycle, and reactive oxygen species (ROS) were studied by flow cytometry (DNA, phospho-histone 3, and CellROX(®) Deep Red) and Western blott…
Liver-specific p38α deficiency causes reduced cell growth and cytokinesis failure during chronic biliary cirrhosis in mice
2012
p38α mitogen-activated protein kinases (MAPK) may be essential in the up-regulation of proinflammatory cytokines and can be activated by transforming growth factor β, tumor necrosis factor-α, interleukin-1β, and oxidative stress. p38 MAPK activation results in hepatocyte growth arrest, whereas increased proliferation has been considered a hallmark of p38α-deficient cells. Our aim was to assess the role of p38α in the progression of biliary cirrhosis induced by chronic cholestasis as an experimental model of chronic inflammation associated with hepatocyte proliferation, apoptosis, oxidative stress, and fibrogenesis. Cholestasis was induced in wildtype and liver-specific p38α knockout mice by…
Mutants of Saccharomyces cerevisiae cell division cycle defective in cytokinesis. Biosynthesis of the cell wall and morphology
1982
The four temperature-sensitive mutants of Saccharomyces cerevisiae in the cell division cycle defective in cytokinesis (cdc, 3, 10, 11 and 12), have been analyzed with respect to the biosynthesis of the cell wall polymers. After 3 hours of incubation at the non-permissive temperature (37 degrees C) these strains stop growing. The synthesis of glucan, mannan and chitin (wall polymers) level off in a similar time, but glucan, mannan and chitin synthases remained active for at least 4 hours. If the mutants are analyzed by transmission and scanning electron microscopy different pictures emerge. Two of the mutants cdc 10 and cdc 12, after 3 hours of incubation at 37 degrees C present apparently …
DNA strand breaks induced by nuclear hijacking of neuronal NOS as an anti-cancer effect of 2-methoxyestradiol
2015
2-Methoxyestradiol (2-ME) is a physiological metabolite of 17β-estradiol. At pharmacological concentrations, 2-ME inhibits colon, breast and lung cancer in tumor models. Here we investigated the effect of physiologically relevant concentrations of 2-ME in osteosarcoma cell model. We demonstrated that 2-ME increased nuclear localization of neuronal nitric oxide synthase, resulting in nitro-oxidative DNA damage. This in turn caused cell cycle arrest and apoptosis in osteosarcoma cells. We suggest that 2-ME is a naturally occurring hormone with potential anti-cancer properties.
Cell Cycle in Potentially Dedifferentiating Cereal Mesophyll Protoplasts Cultured in vitro II. Behaviour of the Cytoskeleton
1993
Summary Following up on the recent finding that mesophyll protoplasts of wheat and oats were able to reenter the cell cycle when cultured in vitro , the behaviour of the cytoskeleton was studied. The aim was to elucidate whether changes in the cytoskeletal patterns correlate with the abnormal progression through the cycle observed previously. Protoplasts freshly isolated from mature mesophyll tissue (type B) exhibited very few, fragmented microtubules, whereas mesophyll protoplasts isolated from immature leaf tissue (type A) showed an abundant network fo microtubules. Type B protoplasts of wheat, which were able to reenter but recalcitrant to complete S-phase, failed to reestablish a microt…