Dataset Information

?- and ?-Actins in the nucleus of human melanoma A375 cells.

ABSTRACT: Actin is a highly conserved protein that is expressed in all eukaryotic cells and has essential functions in the cytoplasm and the nucleus. Nuclear actin is involved in transcription by all three RNA polymerases, chromatin remodelling, RNA processing, intranuclear transport, nuclear export and in maintenance of the nuclear architecture. The nuclear actin level and polymerization state are important factors regulating nuclear processes such as transcription. Our study shows that, in contrast to the cytoplasm, the majority of endogenous nuclear actin is unpolymerized in human melanoma A375 cells. Most mammalian cells express the two non-muscle ?- and ?-actin isoforms that differ in only four amino acids. Despite their sequence similarity, studies analysing the cytoplasmic functions of these isoforms demonstrated that ?- and ?-actins show differences in localization and function. However, little is known about the involvement of the individual actin isoforms in nuclear processes. Here, we used the human melanoma A375 cell line to analyse actin isoforms in regard to their nuclear localization. We show that both ?- and ?-non-muscle actin isoforms are present in nuclei of these cells. Immunolocalization studies demonstrate that both isoforms co-localize with RNA polymerase II and hnRNP U. However, we observe differences in the ratio of cytoplasmic to nuclear actin distribution between the isoforms. We show that ?-actin has a significantly higher nucleus-to-cytoplasm ratio than ?-actin.

SUBMITTER: Migocka-Patrzalek M

PROVIDER: S-EPMC4628621 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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β- and γ-Actins in the nucleus of human melanoma A375 cells.

Migocka-Patrzałek Marta M Makowiecka Aleksandra A Nowak Dorota D Mazur Antonina J AJ Hofmann Wilma A WA Malicka-Błaszkiewicz Maria M

Histochemistry and cell biology 20150804 5

Actin is a highly conserved protein that is expressed in all eukaryotic cells and has essential functions in the cytoplasm and the nucleus. Nuclear actin is involved in transcription by all three RNA polymerases, chromatin remodelling, RNA processing, intranuclear transport, nuclear export and in maintenance of the nuclear architecture. The nuclear actin level and polymerization state are important factors regulating nuclear processes such as transcription. Our study shows that, in contrast to t ...[more]

PMID: 26239425

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Project description:Skin cancer is one of the most common cancers worldwide. Melanoma accounts for ~5% of skin cancers but causes the large majority of skin cancer‑related deaths. Recent discoveries have shown that the mitogen‑activated protein kinase (MAPK) signaling pathway is critical for melanoma development and progression. Many oncogenic pathways that cause melanoma tumorigenesis have been identified, most of which are due to RAF/MEK/ERK (MAPK) pathway activation. However, the precise role of p38 remains unclear. Using specific short hairpin (sh) RNA to silence p38α and p38β, the present findings demonstrated that p38α was a crucial factor in regulating cell migration in the A375 melanoma cell line. Silencing p38α downregulated the expression of epithelial‑mesenchymal transition markers, such as matrix metallopeptidase (MMP) 2, MMP9, twist family bHLH transcription factor 1, snail family transcriptional repressor 1 and vimentin, while mesenchymal‑epithelial transition markers, such as E‑cadherin, were upregulated. Of note, the results also demonstrated that p38α silencing impaired vascular endothelial growth factor expression, which regulates tumor angiogenesis. Furthermore, p38α knockdown inhibited cell proliferation in melanoma cells. In addition, silencing p38α induced senescence‑like features, but not cell cycle arrest. Expression of the senescence markers p16, p21, p53 and β‑galactosidase was upregulated, and an increase in the number of senescence‑associated β‑galactosidase‑positive cells was observed in a p38α knockdown stable clone. However, no significant difference was found between control and p38β stable knockdown cells. Taken together, the present results suggested that p38α knockdown impaired migration and proliferation, and increased senescence, in A375 melanoma cells. However, p38β may not be involved in melanoma tumorigenesis. Therefore, targeting p38α may be a valuable approach towards inhibiting tumor growth and metastasis in patients with melanoma.

Dataset Information

?- and ?-Actins in the nucleus of human melanoma A375 cells.

Publications

β- and γ-Actins in the nucleus of human melanoma A375 cells.

Similar Datasets

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