Tropomyosin is localized in the nuclear matrix and chromosome scaffold of physarum polycephalum

Zeng, Xiaoming; Jiao, Ming Da; Xing, Miao; Wang, Xiao Guang; Hao, Shui

doi:10.1038/sj.cr.7290006

Cited by 7 publications

(2 citation statements)

References 25 publications

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“…Other cytoskeletal proteins have also been found in nuclei (32,33,43,44). Zhao et al (45) recently showed that ␤-actin is a subunit of the SWI/SNI-like BAF (Brg-associated factor) complex in the nucleus and is involved in chromatin remodeling in mammalian cells.…”

Section: Discussionmentioning

confidence: 99%

Cytoplasmic Nuclear Transfer of the Actin-capping Protein Tropomodulin

Kong

Kedes

2004

Journal of Biological Chemistry

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Tropomodulin (Tmod) is a cytoskeletal actin-capping protein that interacts with tropomyosin at the pointed end of actin filaments. E-Tmod is an isoform that expresses predominantly in cardiac cells and slow skeletal muscle fibers. We unexpectedly discovered significant levels of Tmod in nuclei and then defined peptide domains in Tmod responsible for nuclear import and export. These domains resemble, and function as, a nuclear export signal (NES) and a pattern 4 nuclear localization signal (NLS). Both motifs are conserved in other Tmod isoforms and across species. Comparisons of wild-type Tmod and Tmod carrying mutations in these peptide domains revealed that Tmod normally traffics through the nucleus. These observations logically presuppose that Tmod functions may include a nuclear role. Indeed, increasing Tmod in the nucleus severely hampered myogenic differentiation and selectively suppressed muscle-specific gene expression (endogenous p21, myosin heavy chain, myogenin, and Tmod) but did not affect endogenous glyceraldehyde-3-phosphate dehydrogenase or expression from a transfected E-GFP vector. These results suggest that, at least in myogenic cells, nuclear Tmod may be involved in the differentiation process.

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Section: Discussionmentioning

confidence: 99%

Cytoplasmic Nuclear Transfer of the Actin-capping Protein Tropomodulin

Kong

Kedes

2004

Journal of Biological Chemistry

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“…They possess some important biological activities, such as the ability to inhibit mammalian cell division as well as protease, antibiosis, and antitumor activities (Espada et al, 1997). Cytochalasin B (CB) can pass through the cell membrane and bind to F-actin, which inhibits the superposition of G-actins and promotes cytoskeleton depolymerization (Zeng et al, 1997). The cytoskeleton affects cell morphology, cytoplasm flow, chromosome polymerization, and the location and directional movement of nuclei.…”

Section: Introductionmentioning

confidence: 99%

Cytochalasin B inhibits the proliferation of human glioma U251 cells through cell cycle arrest and apoptosis

Zg¹,

Liu²,

Hs³

et al. 2014

Genet. Mol. Res.

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ABSTRACT. Cytochalasin B (CB) is known to inhibit a number of cancer types, but its effects on gliomas are unknown. We examined the in vitro effects of CB on the proliferation of human glioma U251 cells, as well as determined its mechanism of action. Cell proliferation was determined using CCK-8. The effect of CB on U251 cell morphology was observed under a transmission electron microscope. Cell cycle distribution was assessed using propidium iodine and Giemsa staining, and cell apoptosis was determined by annexin V-fluorescein isothiocyanate/propidium iodide. Cell cycle-related proteins were determined by Western blot. CB effectively inhibited U251 cell proliferation in a dose-and time-dependent manner. The 24, 48, 72, and 96 h IC 50 values were 6.41 x 10 -2 , 9.76 x 10 -4 , 2.57 x 10 -5 , and 2.08 x 10 -5 M, respectively. CB increased the proportion of cells in the G2/M phase in a dose-dependent manner, thus increasing the mitotic index and decreasing cdc2 and cyclin B1 protein levels. CB M CB induced apoptosis in 23.4 ± 0.5% of U251 cells (P < 0.05 vs control group). Caspase-3, -8, and -9 activities were increased after CB treatment. CB inhibited U251 glioma cell proliferation by damaging the microfilament structure. CB also induced glioma cell apoptosis, suggesting that it may be an effective therapeutic agent against gliomas.

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Chromosome Scaffold

Pluth¹,

Sridharan²

2013

Brenner's Encyclopedia of Genetics

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GlossaryChromosome organization The ordered progressive hierarchical folding and packaging of a 2-nm double-stranded DNA to form a compacted 1400 nm structure of a metaphase chromosome. Chromosome scaffold A protein framework that acts as a platform for anchoring chromatin loops and defines the shape of the chromosome. Matrix-attached regions (MARs) Intergenic DNA regions, usually near the 5′ ends of genes that bind to the nuclear matrix. A specific DNA sequence motif has been identified in proteins that bind to this region. Scaffold-associated regions (SARs) AT-rich regions in the chromatin that serve as anchoring points to tether the chromatin loops to the chromosome scaffold. Scaffolding proteins A residual network of nonhistone proteins of low abundance identified by the removal of histones, DNA, and RNA from chromosomes. Transcription units Defined regions in the DNA that are flanked by regulatory sequences, which modify genomic expression.

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Tropomyosin is localized in the nuclear matrix and chromosome scaffold of physarum polycephalum

Cited by 7 publications

References 25 publications

Cytoplasmic Nuclear Transfer of the Actin-capping Protein Tropomodulin

Cytoplasmic Nuclear Transfer of the Actin-capping Protein Tropomodulin

Cytochalasin B inhibits the proliferation of human glioma U251 cells through cell cycle arrest and apoptosis

Chromosome Scaffold

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