Arxl functions as an unorthodox nuclear export receptor for the 60S preribosomal subunit
Arxl functions as an unorthodox nuclear export receptor for the 60S preribosomal subunit
复制标题
DOI：
10.1016/j.molcel.2007.06.034
复制
发表时间：
2007-09-07
期刊：
影响因子：
16
通讯作者：
Hurt, Ed
中科院分区：
文献类型：
--
作者：
Bradatsch, Bettina;Katahira, Jun;Hurt, Ed
穿梭转运受体通过与富含 Phe-Gly (FG) 的核孔蛋白的短暂相互作用，通过核孔复合物 (NPC) 携带货物。在这里，我们将 Arx1（一种与细胞核中 60S 晚期核糖体颗粒相关的因子）确定为非常规的输出受体。 Arx1 直接与 FG 核孔蛋白结合，并表现出通过 NPC 促进易位的能力。此外，Arx1 与其他 60S 输出受体 Xpo1 和 Mex67-Mtr2 功能重叠，并且与核孔蛋白有遗传关联。出乎意料的是，Arx1 在结构上与已知的穿梭转运受体无关，但与甲硫氨酸氨基肽酶 (MetAP) 同源，但没有酶活性。通常，MetAP 折叠会形成一个结合蛋氨酸的中心空腔。相反，Arx1 的预测中央腔参与与 FG 重复核孔蛋白和 60S 亚基输出的相互作用。因此，Arx1 采用了一种古老的酶折叠来充当核输出受体。
Shuttling transport receptors carry cargo through nuclear pore complexes (NPCs) via transient interactions with Phe-Gly (FG)-rich nucleoporins. Here, we identify Arx1, a factor associated with a late 60S preribosomal particle in the nucleus, as an unconventional export receptor. Arx1 binds directly to FG nucleoporins and exhibits facilitated translocation through NPCs. Moreover, Arx1 functionally overlaps with the other 60S export receptors, Xpo1 and Mex67-Mtr2, and is genetically linked to nucleoporins. Unexpectedly, Arx1 is structurally unrelated to known shuttling transport receptors but homologous to methionine aminopeptidases (MetAPs), however, without enzymatic activity. Typically, the MetAP fold creates a central cavity that binds the methionine. In contrast, the predicted central cavity of Arx1 is involved in the interaction with FG repeat nucleoporins and 60S subunit export. Thus, an ancient enzyme fold has been adopted by Arx1 to function as a nuclear export receptor.