MOLECULAR DISSECTION OF RADIXIN - DISTINCT AND INTERDEPENDENT FUNCTIONS OF THE AMINO-TERMINAL AND CARBOXY-TERMINAL DOMAINS
MOLECULAR DISSECTION OF RADIXIN - DISTINCT AND INTERDEPENDENT FUNCTIONS OF THE AMINO-TERMINAL AND CARBOXY-TERMINAL DOMAINS
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DOI：
10.1083/jcb.129.4.1007
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发表时间：
1995-05-01
影响因子：
7.8
通讯作者：
SOLOMON, F
中科院分区：
文献类型：
--
作者：
HENRY, MD;AGOSTI, CG;SOLOMON, F
ERM 蛋白（ezrin、radixin 和 moesin）出现在特定的皮质细胞骨架结构中。多项证据表明它们与细胞骨架元素和质膜成分相互作用。在这里，我们描述了在转染细胞中表达的全长和截短的根蛋白多肽的特性。在稳定的转染子中，外源全长根素的行为与内源 ERM 蛋白非常相似，定位于相同的皮质结构。然而，皮质结构中全长根素或其羧基末端结构域的存在与这些结构中内源性模蛋白染色的大大减少相关，这表明根素和模蛋白竞争细胞中正常关联所需的限制因子。结果还揭示了氨基和羧基末端结构域的不同作用。相对于内源性根素而言，羧基末端多肽处于较低水平，与除卵裂沟外的大多数正确皮质靶标相关。相反，氨基末端多肽广泛定位于整个细胞。全长根素或任一截短多肽的低水平表达对细胞生理学没有可检测到的影响。然而，羧基末端结构域的高水平表达会显着破坏正常的细胞骨架结构和功能。在这些高水平下，氨基末端多肽确实定位于皮质结构，但不影响细胞。我们得出的结论是，根素在细胞中的行为取决于蛋白质不同结构域贡献的活性，但也需要调节这些结构域之间的相互作用。
The ERM proteins-ezrin, radixin, and moesin-occur in particular cortical cytoskeletal structures. Several lines of evidence suggest that they interact with both cytoskeletal elements and plasma membrane components. Here we described the properties of full-length and truncated radixin polypeptides expressed in transfected cells. In stable transfectants, exogenous full-length radixin behaves much like endogenous ERM proteins, localizing to the same cortical structures. However, the presence of full-length radixin or its carboxy-terminal domain in cortical structures correlates with greatly diminished staining of endogenous moesin in those structures, suggesting that radixin and moesin compete for a limiting factor required for normal associations in the cell. The results also reveal distinct roles for the amino- and carboxy-terminal domains. At low levels relative to endogenous radixin, the carboxy-terminal polypeptide is associated with most of the correct cortical targets except cleavage furrows. In contrast, the amino-terminal polypeptide is diffusely localized throughout the cell. Low level expression of full-length radixin or either of the truncated polypeptides has no detectable effect on cell physiology. However, high level expression of the carboxy-terminal domain dramatically disrupts normal cytoskeletal structures and functions. At these high levels, the amino-terminal polypeptide does localize to cortical structures, but does not affect the cells. We conclude that the behavior of radixin in cells depends upon activities contributed by separate domains of the protein, but also requires modulating interactions between those domains.