FUNCTIONAL DIFFERENCES BETWEEN L-PLASTIN AND T-PLASTIN ISOFORMS

Citation
M. Arpin et al., FUNCTIONAL DIFFERENCES BETWEEN L-PLASTIN AND T-PLASTIN ISOFORMS, The Journal of cell biology, 127(6), 1994, pp. 1995-2008
Citations number
55
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell Biology
Journal title
ISSN journal
0021-9525
Volume
127
Issue
6
Year of publication
1994
Part
2
Pages
1995 - 2008
Database
ISI
SICI code
0021-9525(1994)127:6<1995:FDBLAT>2.0.ZU;2-L
Abstract
Fimbrins/plastins are a family of highly conserved actin-bundling prot eins. They are present in all eukaryotic cells including yeast, but ea ch isoform displays a remarkable tissue specificity. T-plastin is norm ally found in epithelial and mesenchymal cells while L-plastin is pres ent in hematopoietic cells. However, L-plastin has been also found in tumor cells of non-hematopoietic origin (Lin, C.-S., R. H. Aebersold, S. B. Kent, M. Varma, and J. Leavitt. 1988. Mol. Cell. Biol. 8:4659-46 68; Lin, C.-S., R. H. Aebersold, and J. Leavitt. 1990. Mol. Cell. Biol . 10: 1818-1821). To learn more about the biological significance of t heir tissue specificity, we have overproduced the T- and L-plastin iso forms in a fibroblastlike cell line, CV-1, and in a polarized epitheli al cell line, LLC-PK1. In CV-1 cells, overproduction of T- and L-plast ins induces cell rounding and a concomitant reorganization of actin st ress fibers into geodesic structures. L-plastin remains associated wit h microfilaments while T-plastin is almost completely extracted after treatment of the cells with non-ionic detergent. In LLC-PK1 cells, T-p lastin induces shape changes in microvilli and remains associated with microvillar actin filaments after detergent extraction while L-plasti n has no effect on these structures and is completely extracted. The e ffect of T-plastin on the organization of microvilli differs from that of villin, an other actin-bundling protein. Our experiments indicate that these two isoforms play differing roles in actin filament organiz ation, and do so in a cell type-specific fashion. Thus it is likely th at these plastin isoforms play fundamentally different roles in cell f unction.