Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Genes Dev. 2010 Sep 15;24(18):2043-53. doi: 10.1101/gad.1898610.
The conserved TREX mRNA export complex is known to contain UAP56, Aly, Tex1, and the THO complex. Here, we carried out proteomic analysis of immunopurified human TREX complex and identified the protein CIP29 as the only new component with a clear yeast relative (known as Tho1). Tho1 is known to function in mRNA export, and we provide evidence that CIP29 likewise functions in this process. Like the known TREX components, a portion of CIP29 localizes in nuclear speckle domains, and its efficient recruitment to mRNA is both splicing- and cap-dependent. We show that UAP56 mediates an ATP-dependent interaction between the THO complex and both CIP29 and Aly, indicating that TREX assembly is ATP-dependent. Using recombinant proteins expressed in Escherichia coli, we show that UAP56, Aly, and CIP29 form an ATP-dependent trimeric complex, and UAP56 bridges the interaction between CIP29 and Aly. We conclude that the interaction of two conserved export proteins, CIP29 and Aly, with UAP56 is strictly regulated by ATP during assembly of the TREX complex.
已知保守的 TREX mRNA 输出复合物包含 UAP56、Aly、Tex1 和 THO 复合物。在这里，我们对免疫纯化的人 TREX 复合物进行了蛋白质组学分析，鉴定出蛋白 CIP29 是唯一具有明确酵母对应物（称为 Tho1）的新成分。已知 Tho1 在 mRNA 输出中起作用，我们提供的证据表明 CIP29 同样在此过程中起作用。与已知的 TREX 成分一样，CIP29 的一部分定位于核斑点域，其有效地招募到 mRNA 需要剪接和帽依赖。我们表明 UAP56 介导 THO 复合物与 CIP29 和 Aly 之间的 ATP 依赖性相互作用，表明 TREX 组装是 ATP 依赖性的。使用在大肠杆菌中表达的重组蛋白，我们表明 UAP56、Aly 和 CIP29 形成一个 ATP 依赖性三聚体复合物，并且 UAP56 桥接 CIP29 和 Aly 之间的相互作用。我们得出结论，在 TREX 复合物组装过程中，两个保守的输出蛋白 CIP29 和 Aly 与 UAP56 的相互作用受 ATP 的严格调控。
