Pilkington Guy R, Parker Roy
Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, University of Arizona, 1007 E. Lowell St., Tucson, AZ 85721-0206, USA.
Mol Cell Biol. 2008 Feb;28(4):1298-312. doi: 10.1128/MCB.00936-07. Epub 2007 Dec 17.
The control of mRNA degradation and translation are important aspects of gene regulation. Recent results suggest that translation repression and mRNA decapping can be intertwined and involve the formation of a quiescent mRNP, which can accumulate in cytoplasmic foci referred to as P bodies. The Pat1 protein is a key component of this complex and an important activator of decapping, yet little is known about its function. In this work, we analyze Pat1 in Saccharomyces cerevisiae function by deletion and functional analyses. Our results identify two primary functional domains in Pat1: one promoting translation repression and P-body assembly and a second domain promoting mRNA decapping after assembly of the mRNA into a P-body mRNP. In addition, we provide evidence that Pat1 binds RNA and has numerous domain-specific interactions with mRNA decapping factors. These results indicate that Pat1 is an RNA binding protein and a multidomain protein that functions at multiple stages in the process of translation repression and mRNA decapping.
mRNA降解和翻译的调控是基因调控的重要方面。最近的研究结果表明，翻译抑制和mRNA脱帽可能相互关联，并涉及形成一种静止的mRNA核糖核蛋白（mRNP），这种mRNP可在被称为P小体的细胞质病灶中积累。Pat1蛋白是该复合体的关键组成部分，也是脱帽的重要激活因子，但对其功能了解甚少。在这项工作中，我们通过缺失和功能分析来研究酿酒酵母中Pat1的功能。我们的结果确定了Pat1中的两个主要功能结构域：一个促进翻译抑制和P小体组装，另一个结构域在mRNA组装成P小体mRNP后促进mRNA脱帽。此外，我们提供的证据表明，Pat1与RNA结合，并与mRNA脱帽因子有许多结构域特异性相互作用。这些结果表明，Pat1是一种RNA结合蛋白和多结构域蛋白，在翻译抑制和mRNA脱帽过程的多个阶段发挥作用。
