A tumorigenic actin mutant alters fibroblast morphology and multicellular assembly properties

Blache, Ulrich and Silván, Unai and Plodinec, Marija and Suetterlin, Rosmarie and Jakob, Roman and Klebba, Ina and Bentires-Alj, Mohamed and Aebi, Ueli and Schoenenberger, Cora-Ann. (2013) A tumorigenic actin mutant alters fibroblast morphology and multicellular assembly properties. Cytoskeleton, Vol. 70, H. 10 , S. 635–650.

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Official URL: http://edoc.unibas.ch/dok/A6165218

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Tumor initiation and progression are accompanied by complex changes in the cytoarchitecture that at the cellular level involve remodeling of the cytoskeleton. We report on the impact of a mutant β-actin (G245D-actin) on cell structure and multicellular assembly properties. To appreciate the effects of the Gly245Asp substitution on the organization of the actin cytoskeleton, we examined the polymerization properties of G245D-actin in vitro by pyrene polymerization assays and total internal reflection fluorescence microscopy (TIRF). The mutant actin on its own has a significantly reduced polymerization efficiency compared to native actin but also modifies the polymerization of actin in copolymerization experiments. Comparison of the structure of Rat-2 fibroblasts and a stably transfected derivate called Rat-2-sm9 revealed the effects of G245D-actin in a cellular environment. The overall actin levels in Rat-2-sm9 show a 1.6-fold increase with similar amounts of mutant and wild-type actin. G245D-actin expression renders Rat-2-sm9 cells highly tumorigenic in nude mice. In Rat-2-sm9 monolayers, G245D-actin triggers the formation of extensive membrane ruffles, which is a characteristic feature of many transformed cells. To approximate complex cell-cell and cell-matrix interactions that occur in tumors and might modulate the effects of G245D-actin, we extended our studies to scaffold-free 3D spheroid cultures. Bright field and scanning electron microscopy (SEM) show that Rat-2-sm9 and Rat-2 cells share essential features of spheroid formation and compaction. However, the resulting spheroids exhibit distinct phenotypes that differ mainly in surface structure and size. The systematic comparison of transformed and normal spheroids by SEM provides new insights into scaffold-free fibroblast spheroid formation. © 2013 Wiley Periodicals, Inc.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Former Organization Units Biozentrum > Structural Biology (Schoenenberger)
UniBasel Contributors:Schoenenberger, Cora-Ann and Plodinec, Marija and Jakob, Roman Peter and Sütterlin, Rosmarie
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:20 Jun 2014 07:56
Deposited On:20 Jun 2014 07:56

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