Complex relationship between TCTP, microtubules and actin microfilaments regulates cell shape in normal and cancer cells
Complex relationship between TCTP, microtubules and actin microfilaments regulates cell shape in normal and cancer cells
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DOI：
10.1093/carcin/bgp022
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发表时间：
2009-04-01
期刊：
影响因子：
4.7
通讯作者：
Kubiak, Jacek Z.
中科院分区：
文献类型：
--
作者：
Bazile, Franck;Pascal, Aude;Kubiak, Jacek Z.
翻译控制的肿瘤相关蛋白（TCTP）是一种普遍存在的高度保守的蛋白质，与癌症有关。在这里，我们证明了TCTP与微管（MT）的相互作用在功能上是重要的，但间接的，我们揭示了新的TCTP与肌动蛋白细胞骨架的相互作用。首先，非洲爪蟾XL 2细胞中的免疫荧光显示细胞质纤维用TCTP染色，但不与微管蛋白抗体，以及MTs的TCTP自由。此外，TCTP定位于迁移细胞中富含肌动蛋白的纤维的子集。其次，非洲爪蟾TCTP不影响MT的体外组装/拆卸，并且在下拉试验和无细胞提取物中均缺乏MT结合亲和力。虽然TCTP也未能结合到纯化的丝状肌动蛋白（F-肌动蛋白），它与无细胞提取物中的微丝。第三，TCTP集中在有丝分裂纺锤体不与MTs共定位，很容易从这些结构中分离，除了在两极。最后，RNA干扰敲低XL 2和HeLa细胞中的TCTP引起剧烈的MT依赖性形状变化。这些数据表明，虽然TCTP与MT相互作用，但它并不表现为经典的MT相关蛋白。我们的证据表明TCTP与F-肌动蛋白结构的关联，并参与细胞形状调节，暗示这种蛋白质在整合细胞骨架的相互作用，在间期和有丝分裂提供了一个新的途径，以充分了解TCTP的作用。
Translationally controlled tumor-associated protein (TCTP) is a ubiquitous and highly conserved protein implicated in cancers. Here, we demonstrate that interactions of TCTP with microtubules (MTs) are functionally important but indirect, and we reveal novel interaction of TCTP with the actin cytoskeleton. Firstly, immunofluorescence in Xenopus XL2 cells revealed cytoplasmic fibers stained with TCTP but not with tubulin antibodies, as well as MTs free of TCTP. Furthermore, TCTP localized to a subset of actin-rich fibers in migrating cells. Secondly, Xenopus laevis TCTP did not affect in vitro assembly/disassembly of MTs and lacked MT-binding affinity both in pull-down assays and in cell-free extracts. Although TCTP also failed to bind to purified filamentous actin (F-actin), it was associated with microfilaments in cell-free extracts. Thirdly, TCTP concentrated in mitotic spindle did not colocalize with MTs and was easily dissociated from these structures except at the poles. Finally, RNA interference knockdown of TCTP in XL2 and HeLa cells provoked drastic, MT-dependent shape change. These data show that although TCTP interacts with MTs, it does not behave as classic MT-associated protein. Our evidence for an association of TCTP with F-actin structures, and for an involvement in cell shape regulation, implicates this protein in integrating cytoskeletal interactions both in interphase and mitosis providing a new avenue to fully understand the role of TCTP.