Search results for "nucleus"

2015

In many technical applications, but also in natural processes like ice nucleation in clouds, crystallization proceeds in the presence of stresses and flows, hence the importance to understand the crystallization mechanism in simple situations. We employ molecular dynamics simulations to study the crystallization kinetics of a nearly hard sphere liquid that is weakly sheared. We demonstrate that shear flow both enhances and suppresses the crystallization kinetics of hard spheres. The effect of shear depends on the quiescent mechanism: suppression in the activated regime and enhancement in the diffusion-limited regime for small strain rates. At higher strain rates crystallization again become…

Calmodulin binds to p21(Cip1) and is involved in the regulation of its nuclear localization.

1999

p21(Cip1), first described as an inhibitor of cyclin-dependent kinases, has recently been shown to have a function in the formation of cyclin D-Cdk4 complexes and in their nuclear translocation. The dual behavior of p21(Cip1) may be due to its association with other proteins. Different evidence presented here indicate an in vitro and in vivo interaction of p21(Cip1) with calmodulin: 1) purified p21(Cip1) is able to bind to calmodulin-Sepharose in a Ca(2+)-dependent manner, and this binding is inhibited by the calmodulin-binding domain of calmodulin-dependent kinase II; 2) both molecules coimmunoprecipitate when extracted from cellular lysates; and 3) colocalization of calmodulin and p21(Cip…

Myc Promoter-Binding Protein-1 (MBP-1) Is a Novel Potential Prognostic Marker in Invasive Ductal Breast Carcinoma

2010

BackgroundAlpha-enolase is a glycolytic enzyme that catalyses the formation of phosphoenolpyruvate in the cell cytoplasm. α-Enolase and the predominantly nuclear Myc promoter-binding protein-1 (MBP-1) originate from a single gene through the alternative use of translational starting sites. MBP-1 binds to the P2 c-myc promoter and competes with TATA-box binding protein (TBP) to suppress gene transcription. Although several studies have shown an antiproliferative effect of MBP-1 overexpression on several human cancer cells, to date detailed observations of α-enolase and MBP-1 relative expression in primary tumors versus normal tissues and their correlation with clinicopathological features ha…

Nuclear and Cytoplasmic Survivin: Molecular Mechanism, Prognostic, and Therapeutic Potential.

2007

Abstract Survivin's proposed dual role as an apoptosis inhibitor and a mitotic effector positioned it in the front line of cancer research. Notably, survivin is detected as a cytoplasmic and nuclear protein in cancer patients, which stimulated numerous studies to investigate and to speculate on the functional and prognostic significance of its dynamic localization. Recent evidence shows that the direct interaction of survivin with the nuclear export receptor Crm1 is critically involved in its intracellular localization and cancer-relevant functions. Here, we review our current understanding of the Crm1/survivin interface and discuss its potential prognostic and therapeutic relevance. [Cance…

Glutathione is recruited into the nucleus in early phases of cell proliferation.

2007

We have studied the possible correlation between nuclear glutathione distribution and the progression of the cell cycle. The former was studied by confocal microscopy using 5-chloromethyl fluorescein diacetate and the latter by flow cytometry and protein expression of Id2 and p107. In proliferating cells, when 41% of them were in the S+G(2)/M phase of the cell cycle GSH was located mainly in the nucleus. When cells reached confluence (G(0)/G(1)) GSH was localized in the cytoplasm with a perinuclear distribution. The nucleus/cytoplasm fluorescence ratio for GSH reached a maximal mean value of 4.2 +/- 0.8 at 6 h after cell plating. A ratio higher than 2 was maintained during exponential cell …

Study of the Evolutionary Relationships among Limonium Species (Plumbaginaceae) Using Nuclear and Cytoplasmic Molecular Markers

2000

The genus Limonium, due to the patchiness of the natural habitats of its species as well as the high frequency of hybridization and polyploidy and the possibility of reproduction by apomixis, provides an example of all the principal mechanisms of rapid speciation of plants. As an initial study of evolution in this genus, we have analyzed intra- and interspecific variability in 17 species from section Limonium, the largest in the genus, based on RFLPs of cpDNA and nuclear rDNA ITS sequences. In the cpDNA analysis, 21 restriction enzymes were used, resulting in 779 fragments, 490 of which were variable and 339 parsimony informative. L. furfuraceum exhibited two relatively divergent cpDNA hapl…

Nuclear Translocation of Mismatch Repair Proteins MSH2 and MSH6 as a Response of Cells to Alkylating Agents

2000

Mammalian mismatch repair has been implicated in mismatch correction, the prevention of mutagenesis and cancer, and the induction of genotoxicity and apoptosis. Here, we show that treatment of cells specifically with agents inducing O(6)-methylguanine in DNA, such as N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea, elevates the level of MSH2 and MSH6 and increases GT mismatch binding activity in the nucleus. This inducible response occurs immediately after alkylation, is long-lasting and dose-dependent, and results from translocation of the preformed MutSalpha complex (composed of MSH2 and MSH6) from the cytoplasm into the nucleus. It is not caused by an increase in MSH2 gen…

Deciliation: A stressful event for Paracentrotus lividus embryos.

1998

In this report, by using mono- and two-dimensional electrophoretic analysis, we demonstrate that deciliation on sea urchin embryos induces a stress response. Deciliation indeed causes not only the activation of ciliary subroutine, but also a transient decrease of bulk protein synthesis. This decrease is in agreement with our previous results on heat shock response in sea urchin, although deciliation does not induce the expression of the same main hsp set. We were able to characterize one main deciliation-stress protein of 40 kDa whose expression is transiently induced by deciliation and whose localisation is likely to be nuclear.

Translocation of cdk2 to the nucleus during G1-phase in PDGF-stimulated human fibroblasts.

1997

We studied the subcellular distribution of cdk2 in synchronized, PDGF-stimulated human fibroblasts (FH109). After contact inhibition and serum depletion, more than 95% of FH109 cells were arrested in G0/G1-phase. PDGF-AB led to a 16-fold increase in proliferation compared with untreated cells. Cell cycle progression was studied by flow cytometric analysis, [3H]thymidine incorporation, and phosphorylation of the retinoblastoma gene product, pRB. Using Western blot analysis after subcellular fractionation, we revealed that after PDGF stimulation the phosphorylated (Thr 160), i.e., activated, form of cdk2 (33 kDa) first appeared in the nucleus at late G1-phase and persisted throughout until to…

The La antigen shuttles between the nucleus and the cytoplasm in CV-1 cells

1989

Recently we established a monoclonal antibody against the La-protein (Bachmann et al., Proc. Natl. Acad. Sci. USA, 83, 7770, 1986). The antibody gives a nuclear speckled type staining and, in addition, a perinuclear cytoplasmic staining on cultured cells in immunofluorescence microscopy. After inhibition of RNA synthesis the La-protein is transported into the cytoplasm. After prolonged inhibition it returns into the nucleus forming large growing speckles. The transport into the nucleus apparently depends on glycosylation.