Interaction of the taxilin family with the nascent polypeptide-associated complex that is involved in the transcriptional and translational processes
Interaction of the taxilin family with the nascent polypeptide-associated complex that is involved in the transcriptional and translational processes
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DOI：
10.1111/j.1365-2443.2005.00848.x
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发表时间：
2005-05-01
期刊：
影响因子：
2.1
通讯作者：
Shirataki, H
中科院分区：
文献类型：
--
作者：
Yoshida, K;Nogami, S;Shirataki, H
α-Taxilin是突触融合蛋白家族的一种新的结合伴侣，其参与胞内囊泡运输。我们在这里发现，α-紫杉素与新生多肽相关复合物（NAC）相互作用，该复合物参与将生长的新生多肽链转移到适当的共翻译作用因子。NAC由两个亚基，α-和β NAC组成。这两种亚基通过其C-末端卷曲螺旋区域以剂量依赖性和饱和的方式与α-紫杉素结合。α-紫杉素与α-NAC和NAC的相互作用但不与β-NAC的相互作用被突触融合蛋白-4抑制，表明α-紫杉素主要通过其与α-NAC的相互作用与NAC结合。当α NAC在COS-7细胞中过表达时，α NAC分布在胞浆和细胞核中。然而，含有α NAC结合区的α-紫杉素片段的共表达消除了过表达α NAC的核分布。此外，其他紫杉素家族成员，β-和γ-紫杉素，也结合到α NAC，从而影响过表达的α NAC的核分布。两者结合的证据表明，α NAC的功能在细胞核中作为一个转录辅激活因子，我们的研究结果提出的可能性，紫杉醇家族参与不仅在翻译过程中，通过与NAC的相互作用，但也在转录过程中，通过其与α NAC单独的相互作用。
alpha-Taxilin is a novel binding partner of the syntaxin family, which is implicated in intracellular vesicle traffic. We have here found that alpha-taxilin interacts with the nascent polypeptide-associated complex (NAC), which is involved in transferring growing nascent polypeptide chains to appropriate co-translationally acting factors. NAC is composed of two subunits, alpha- and beta NACs. Both these subunits bound to alpha-taxilin through its C-terminal coiled-coil region in dose-dependent and saturable manners. The interactions of alpha-taxilin with alpha NAC and NAC but not with beta NAC were inhibited by syntaxin-4, indicating that alpha-taxilin binds to NAC mainly through its interaction with alpha NAC. When alpha NAC was over-expressed in COS-7 cells, alpha NAC was distributed in the cytosol and nucleus. However, co-expression of the alpha-taxilin fragment containing the alpha NAC-binding region eliminated the nuclear distribution of over-expressed alpha NAC. Moreover, other taxilin family members, beta- and gamma-taxilins, also bound to alpha NAC and thereby affected the nuclear distribution of over-expressed alpha NAC. Taken together with the evidence that alpha NAC functions in the nucleus as a transcriptional coactivator, our results raise the possibility that the taxilin family is involved not only in the translational process through its interaction with NAC but also in the transcriptional process through its interaction with alpha NAC alone.