The pre-mRNA-splicing factor SF3a66 functions as a microtubule-binding and -bundling protein
The pre-mRNA-splicing factor SF3a66 functions as a microtubule-binding and -bundling protein
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DOI：
10.1042/bj20040521
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发表时间：
2004-08-15
影响因子：
4.1
通讯作者：
Miki, H
中科院分区：
文献类型：
--
作者：
Takenaka, K;Nakagawa, H;Miki, H
SF 3a（splicing factor 3a）复合物是小核核糖核蛋白颗粒（small nuclear ribonucleoprotein particles，snRNP）的重要组成部分，参与前体mRNA的剪接。该复合物由三个亚基组成：SF 3a 60，SF 3a 66和SF 3a 120在这里，我们报告了一个可能的非典型功能的一个良好的特征RNA剪接因子，SF 3a 66。在N1 E 115神经母细胞瘤细胞中使用每个SF 3a亚基的异位表达实验揭示，SF 3a 66单独可以诱导神经突延伸，表明SF 3a 66在细胞形态的调节中起作用。筛选与SF 3a 66结合的蛋白阐明了SF 3a 66以高亲和力与β-微管蛋白结合，也与微管结合，表明SF 3a 66是一种新的MAP（微管相关蛋白）。电子显微镜实验表明，SF 3a 66可以捆绑微管，而微管的捆绑是由于微管的交联由低聚SF 3a 66的高分子量复合物。这些结果表明，SF 3a 66可能是一种新的MAP，并且可以独立于RNA剪接发挥微管捆绑蛋白的功能。
SF3a (splicing factor 3a) complex is an essential component of U2 snRNPs (small nuclear ribonucleoprotein particles), which are involved in pre-mRNA splicing. This complex consists of three subunits: SF3a60, SF3a66 and SF3a120 Here, we report a possible non-canonical function of a well-characterized RNA-splicing factor, SF3a66. Ectopic expression experiments using each SF3a subunit in N1E 115 neuroblastoma cells reveals that SF3a66 alone can induce neurite extension, suggesting that SF3a66 functions in the regulation of cell morphology. A screen for proteins that bind to SF3a66 clarifies that SF3a66 binds to beta-tubulin, and also to microtubules, with high affinity, indicating that SF3a66 is a novel MAP (microtubule-associated protein). Electron microscopy experiments show that SF3a66 can bundle microtubules, and that bundling of microtubules is due to crossbridging of microtubules by high-molecular-mass complexes of oligomerized SF3a66. These results indicate that SF3a66 is likely to be a novel MAP, and can function as a microtubule-bundling protein independently of RNA splicing.