Functional differences between L- and T-plastin isoforms.
Functional differences between L- and T-plastin isoforms.
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DOI：
10.1083/jcb.127.6.1995
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发表时间：
1994-12
期刊：
影响因子：
--
通讯作者：
Louvard D
中科院分区：
文献类型：
--
作者：
Arpin M;Friederich E;Algrain M;Vernel F;Louvard D
纤溶蛋白/塑性蛋白是一类高度保守的肌动蛋白结合蛋白。它们存在于包括酵母在内的所有真核细胞中，但每种异构体都表现出显著的组织特异性。T-plastin通常存在于上皮细胞和间充质细胞中，而L-plastin存在于造血细胞中。然而，l -活蛋白也在非造血来源的肿瘤细胞中被发现(Lin， C.-S.；， r.h.a ebersold, s.b.k Kent， M. Varma， J. Leavitt. 1988。摩尔。细胞。生物8:4659 - 4668;林,c。R. H.埃伯索德，J.莱维特。1990。摩尔。细胞。《圣经》10:18 -1821)。为了进一步了解其组织特异性的生物学意义，我们在成纤维细胞样细胞系CV-1和极化上皮细胞系LLC-PK1中过量生产了T-和l -活质素同种异构体。在CV-1细胞中，T-和l -质体的过量产生诱导细胞变圆，并伴随肌动蛋白应力纤维重组为测地线结构。L-活质仍与微丝相关，而t -活质经非离子去污剂处理后几乎完全被提取。在lc - pk1细胞中，t -活蛋白诱导微绒毛的形状变化，并在洗涤剂提取后仍与微绒毛肌动蛋白丝相关，而l -活蛋白对这些结构没有影响，并被完全提取。t -活蛋白对微绒毛组织的影响不同于另一种肌动蛋白捆绑蛋白绒毛蛋白。我们的实验表明，这两种异构体在肌动蛋白丝组织中起着不同的作用，并且以细胞类型特异性的方式起作用。因此，很可能这些活质异构体在细胞功能中起着根本不同的作用。
Fimbrins/plastins are a family of highly conserved actin-bundling proteins. They are present in all eukaryotic cells including yeast, but each isoform displays a remarkable tissue specificity. T-plastin is normally found in epithelial and mesenchymal cells while L-plastin is present 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. 8:4659-4668; Lin, C.-S., R. H. Aebersold, and J. Leavitt. 1990. Mol. Cell. Biol. 10: 1818-1821). To learn more about the biological significance of their tissue specificity, we have overproduced the T- and L-plastin isoforms in a fibroblast-like cell line, CV-1, and in a polarized epithelial cell line, LLC-PK1. In CV-1 cells, overproduction of T- and L-plastins induces cell rounding and a concomitant reorganization of actin stress fibers into geodesic structures. L- plastin remains associated with microfilaments while T-plastin is almost completely extracted after treatment of the cells with non-ionic detergent. In LLC-PK1 cells, T-plastin induces shape changes in microvilli and remains associated with microvillar actin filaments after detergent extraction while L-plastin has no effect on these structures and is completely extracted. The effect of T-plastin on the organization of microvilli differs from that of villin, another actin- bundling protein. Our experiments indicate that these two isoforms play differing roles in actin filament organization, and do so in a cell type-specific fashion. Thus it is likely that these plastin isoforms play fundamentally different roles in cell function.