Department of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston, Houston, Texas, USA.
Adv Exp Med Biol. 2011;702:79-90. doi: 10.1007/978-1-4419-7841-7_7.
The exosome consists of a core of ten essential proteins that includes the ribonuclease Rrp44p and is present in both the cytoplasm and nucleus of eukaryotic cells. The cytoplasmic exosome has been extensively characterized in the budding yeast Saccharomyces cerevisiae and some characterization of its metazoan counterpart indicates that most functional aspects are conserved. These studies have implicated the cytoplasmic exosome in the turnover of normal cellular mRNAs, as well as several mRNA surveillance pathways. For this, the exosome needs a set of four proteins that do not partake in nuclear exosome functions. These cofactors presumably direct the exosome to specific cytoplasmic RNA substrates. Here, we review cofactors and functions of the cytoplasmic exosome and provide unanswered questions on the mechanisms of cytoplasmic exosome function.
外切体由包含核糖核酸酶 Rrp44p 的十个必需蛋白核心组成，存在于真核细胞的细胞质和细胞核中。出芽酵母酿酒酵母中的细胞质外切体已得到广泛研究，对其后生动物对应物的一些特征表明，大多数功能方面是保守的。这些研究表明，细胞质外切体参与正常细胞 mRNA 的周转，以及几种 mRNA 监测途径。为此，外切体需要一组不参与核外切体功能的四种蛋白质。这些辅助因子可能将外切体导向特定的细胞质 RNA 底物。在这里，我们综述了细胞质外切体的辅助因子和功能，并提供了关于细胞质外切体功能机制的未解决问题。
