Functional overlap between conserved and diverged KH domains in Saccharomyces cerevisiae SCP160
Functional overlap between conserved and diverged KH domains in Saccharomyces cerevisiae SCP160
复制标题
DOI：
10.1093/nar/gkl1160
复制
发表时间：
2007-02-01
影响因子：
14.9
通讯作者：
Fridovich-Keil, Judith L.
中科院分区：
文献类型：
--
作者：
Brykailo, Melissa A.;Corbett, Anita H.;Fridovich-Keil, Judith L.
K同源（KH）结构域是一个非常通用和高度保守的RNA结合基序。经典的KH结构域包括疏水残基的特征模式、Gly-X-X-Gly（GXXG）区段和可变环。KH结构域通常成簇出现，其中一些保留其GXXG序列（保守），而另一些不保留（发散）。作为解决GXXG是否对KH结构域功能至关重要的第一步，我们探讨了Scp160p中保守和分歧的KH结构域的作用，Scp160p是酿酒酵母中含有多个KH结构域的蛋白质。我们特别想知道（1）是否分歧KH结构域是必不可少的Scp160p功能，（2）是否分歧KH结构域可以在功能上取代保守的KH结构域。为了解决这些问题，我们删除和/或交换的Scp160 p的保守和分歧KH结构域，并在酵母中表达突变的等位基因。我们的结果表明，每个问题的答案都是肯定的。保守和分歧的KH结构域是必不可少的Scp160 p的功能，和分歧的KH结构域可以在保守的KH结构域的地方发挥作用。这些发现挑战了关于KH结构域的必要特征的流行观念，并提出了蛋白质组中可能存在比以前认识到的更多功能性KH结构域的可能性。
The K homology (KH) domain is a remarkably versatile and highly conserved RNA-binding motif. Classical KH domains include a characteristic pattern of hydrophobic residues, a Gly-X-X-Gly (GXXG) segment, and a variable loop. KH domains typically occur in clusters, with some retaining their GXXG sequence (conserved), while others do not (diverged). As a first step towards addressing whether GXXG is essential for KH-domain function, we explored the roles of conserved and diverged KH domains in Scp160p, a multiple-KH-domain-containing protein in Saccharomyces cerevisiae. We specifically wanted to know (1) whether diverged KH domains were essential for Scp160p function, and (2) whether diverged KH domains could functionally replace conserved KH domains. To address these questions, we deleted and/or interchanged conserved and diverged KH domains of Scp160p and expressed the mutated alleles in yeast. Our results demonstrated that the answer to each question was yes. Both conserved and diverged KH domains are essential for Scp160p function, and diverged KH domains can function in place of conserved KH domains. These findings challenge the prevailing notions about the requisite features of a KH domain and raise the possibility that there may be more functional KH domains in the proteome than previously appreciated.