Nuclear actin filaments recruit cofilin and actin-related protein 3, and their formation is connected with a mitotic block
| Autor: | Pavel Hozák, Alžběta Kalendová, Ilona Kalasova, Lívia Uličná, Masahiko Harata, Shota Yamazaki |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Histology
Transcription Genetic Actin-related protein 3 Mitosis Arp2/3 complex macromolecular substances Bacterial Proteins RNA Polymerase I Cell Line Tumor Humans Intermediate filament Cytoskeleton Molecular Biology Actin nucleation Cell Nucleus Original Paper biology Actin remodeling Cell Biology Cofilin Chromatin Assembly and Disassembly Actins Cell biology Actin Cytoskeleton Luminescent Proteins Medical Laboratory Technology HEK293 Cells Treadmilling Actin Depolymerizing Factors Nuclear actin biology.protein RNA Polymerase II Transcription Lamin |
| Zdroj: | Histochemistry and Cell Biology |
| ISSN: | 0948-6143 |
| DOI: | 10.1007/s00418-014-1243-9 |
| Popis: | Although actin monomers polymerize into filaments in the cytoplasm, the form of actin in the nucleus remains elusive. We searched for the form and function of β-actin fused to nuclear localization signal and to enhanced yellow fluorescent protein (EN-actin). Our results reveal that EN-actin is either dispersed in the nucleoplasm (homogenous EN-actin) or forms bundled filaments in the nucleus (EN-actin filaments). Formation of such filaments was not connected with increased EN-actin levels. Among numerous actin-binding proteins tested, only cofilin is recruited to the EN-actin filaments. Overexpression of EN-actin causes increase in the nuclear levels of actin-related protein 3 (Arp3). Although Arp3, a member of actin nucleation complex Arp2/3, is responsible for EN-actin filament nucleation and bundling, the way cofilin affects nuclear EN-actin filaments dynamics is not clear. While cells with homogenous EN-actin maintained unaffected mitosis during which EN-actin re-localizes to the plasma membrane, generation of nuclear EN-actin filaments severely decreases cell proliferation and interferes with mitotic progress. The introduction of EN-actin manifests in two mitotic-inborn defects—formation of binucleic cells and generation of micronuclei—suggesting that cells suffer aberrant cytokinesis and/or impaired chromosomal segregation. In interphase, nuclear EN-actin filaments passed through chromatin region, but do not co-localize with either chromatin remodeling complexes or RNA polymerases I and II. Surprisingly presence of EN-actin filaments was connected with increase in the overall transcription levels in the S-phase by yet unknown mechanism. Taken together, EN-actin can form filaments in the nucleus which affect important cellular processes such as transcription and mitosis. |
| Databáze: | OpenAIRE |
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