Matzat Leah H, Berberoglu Stephen, Lévesque Lyne
Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Mol Biol Cell. 2008 Jan;19(1):327-38. doi: 10.1091/mbc.e07-03-0255. Epub 2007 Oct 31.
Nuclear export of mRNAs is mediated by the Tap/Nxt1 pathway. Tap moves its RNA cargo through the nuclear pore complex by direct interaction with nucleoporin phenylalanine-glycine repeats. This interaction is strengthened by the formation of a Tap/Nxt1 heterodimer. We now present evidence that Tap can form a multimeric complex with itself and with other members of the NXF family. We also show that the homotypic Tap complex can interact with both Nxt1 and nucleoporins in vitro. The region mediating this oligomerization is localized to the first 187 amino acids of Tap, which overlaps with its RNA-binding domain. Removal of this domain greatly reduces the ability of Tap to bind nucleoporins in vitro and in vivo. This is the first report showing that the Tap amino terminus modulates the interaction of Tap with nucleoporins. We speculate that this mechanism has a regulatory role for RNA export independent of RNA binding.
mRNA的核输出由Tap/Nxt1途径介导。Tap通过与核孔蛋白苯丙氨酸-甘氨酸重复序列直接相互作用，将其RNA货物转运通过核孔复合体。Tap/Nxt1异二聚体的形成会加强这种相互作用。我们现在提供证据表明，Tap可以与自身以及NXF家族的其他成员形成多聚体复合物。我们还表明，同型Tap复合物在体外可与Nxt1和核孔蛋白相互作用。介导这种寡聚化的区域定位于Tap的前187个氨基酸，该区域与其RNA结合结构域重叠。去除该结构域会大大降低Tap在体外和体内结合核孔蛋白的能力。这是首次报道表明Tap氨基末端调节Tap与核孔蛋白的相互作用。我们推测这种机制对RNA输出具有独立于RNA结合的调节作用。
