Search PubMedSearch

PubMed · 7488128

Decrease in actin gene expression in melanoma cells compared to melanocytes is partly counteracted by BrdU-induced cell adhesion and antagonized by L-tyrosine induction of terminal differentiation.

Abstract

Malignant transformation is frequently accompanied by changes in the cytoarchitecture of adherent cells, which may be influenced by fluctuations in actin gene expression. We now show that normal melanocytes express a 5 fold higher level of actin mRNA than their melanoma counterparts. Induction of terminal melanogenesis did not increase actin in melanoma cells. However, culture with the thymidine analog, Bromodeoxyuridine, increased actin expression in undifferentiated but not in differentiating melanoma. Cell detachment assays and cell shape comparisons revealed a direct correlation of actin mRNA with increased melanoma cell adhesion rather than with differentiation-mediated suppression of tumor growth.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

L A Gómez, M Strasberg Rieber, M Rieber. 1995-11-02. Decrease in actin gene expression in melanoma cells compared to melanocytes is partly counteracted by BrdU-induced cell adhesion and antagonized by L-tyrosine induction of terminal differentiation.. https://doi.org/10.1006/bbrc.1995.2595

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Nap1-mediated actin remodeling is essential for mammalian myoblast fusion.

Myoblast fusion is crucial for the formation, growth, maintenance and regeneration of healthy skeletal muscle. Unfortunately, the molecular machinery, cell behaviors, and membrane and cytoskeletal remodeling events that govern fusion and myofiber formation remain poorly understood. Using time-lapse imaging approaches on mouse C2C12 myoblasts, we identify discrete and specific molecular events at myoblast membranes during fusion and myotube formation. These events include rearrangement of cell shape from fibroblast to spindle-like morphologies, changes in lamellipodial and filopodial extensions during different periods of differentiation, and changes in membrane alignment and organization during fusion. We find that actin-cytoskeleton remodeling is crucial for these events: pharmacological inhibition of F-actin polymerization leads to decreased lamellipodial and filopodial extensions and to reduced myoblast fusion. Additionally, shRNA-mediated inhibition of Nap1, a member of the WAVE actin-remodeling complex, results in accumulations of F-actin structures at the plasma membrane that are concomitant with a decrease in myoblast fusion. Our data highlight distinct and essential roles for actin cytoskeleton remodeling during mammalian myoblast fusion, provide a platform for cellular and molecular dissection of the fusion process, and suggest a functional conservation of Nap1-regulated actin-cytoskeleton remodeling during myoblast fusion between mammals and Drosophila.

Actins

Direct binding of F actin to the cytoplasmic domain of the alpha 2 integrin chain in vitro.

The transmembrane integrins have been shown to interact with the cytoskeleton via noncovalent binding between cytoplasmic domains (CDs) of integrin beta chains and various actin binding proteins within the focal adhesion complex. Direct or indirect integrin alpha chain CD binding to the actin cytoskeleton has not been reported. We show here that actin, as an abundant constituent of focal adhesion complex proteins isolated from fibroblasts, binds strongly and specifically to alpha 2 CD, but not to alpha 1 CD peptide. Similar specific binding to alpha 2 CD peptide was seen for highly purified F actin, free of putative actin-binding proteins. The bound complex of actin and peptide was visualized directly by coprecipitation, and actin binding was abrogated by removal of a five amino acid sequence from the alpha 2 CD peptide. Our findings may explain the earlier observation that, while integrins alpha 2 beta 1 and alpha 1 beta 1 both bind to collagen, only alpha 2 beta 1 can mediate contraction of extracellular collagen matrices.

Actins