Autoproteolysis in nucleoporin biogenesis
Autoproteolysis in nucleoporin biogenesis
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DOI：
10.1073/pnas.96.20.11370
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发表时间：
1999-09-28
影响因子：
11.1
通讯作者：
Blobel, G
中科院分区：
文献类型：
--
作者：
Rosenblum, JS;Blobel, G
我们的分子特征的保守核孔复合物蛋白质的蛋白水解裂解。这种切割，以前证明是必不可少的两个核孔复合物蛋白在哺乳动物（Nup 98和Nup 96）和酵母（Nup 145-N和Nup 145-C）的生物合成，发生在Phe和Ser残基之间的一个高度保守的结构域中的多蛋白前体。在这里，我们表明，蛋白酶不参与切割事件。通过使用结构域定位和定点诱变的组合，我们证明了人核孔复合物蛋白Nup 98特异性地在F863和S864之间切割自身。Nup 98的氨基酸715-920的区域能够切割，而较小的氨基酸772-920的区域不切割。此外，我们已经产生了在体外限定条件下切割的Nup 98突变体。此外，Nup 98的两个切割片段形成复合物，提供了一种可能的机制，其中Nup 98和Nup 96之间的特异性但低亲和力的结合负责Nup 96的核靶向。虽然显然无关的进化，Nup 98已经收敛于一个类似于刺猬蛋白，内含肽，N-末端亲核蛋白的自蛋白水解生物合成机制。
We have molecularly characterized a proteolytic cleavage in conserved nuclear pore complex proteins. This cleavage, previously demonstrated to be essential for the biogenesis of two nuclear pore complex proteins in mammals (Nup98 and Nup96) and yeast (Nup145-N and Nup145-C), occurs between Phe and Ser residues within a highly conserved domain in a polyprotein precursor. Here, we show that a protease is not involved in the cleavage event. By using a combination of domain mapping and site-directed mutagenesis, we demonstrate that the human nuclear pore complex protein Nup98 specifically cleaves itself between F863 and S864. A region of Nup98, amino acids 715-920, is able to cleave, whereas a smaller region, amino acids 772-920, does not cleave. In addition, we have generated a Nup98 mutant that cleaves under defined conditions in vitro. Further, the two cleaved fragments of Nup98 form a complex, providing a possible mechanism whereby specific, yet low-affinity, binding between Nup98 and Nup96 is responsible for the nuclear targeting of Nup96. Although apparently unrelated evolutionarily, Nup98 has converged on an autoproteolytic biogenesis mechanism similar to that of hedgehog proteins, the inteins, and the N-terminal nucleophile proteins.