Chapter

RNA Exosome

Volume 702 of the series Advances in Experimental Medicine and Biology pp 79-90

Functions of the Cytoplasmic Exosome

  • Daneen SchaefferAffiliated withDepartment of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston
  • , Amanda ClarkAffiliated withDepartment of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston
  • , A. Alejandra KlauerAffiliated withDepartment of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston
  • , Borislava TsanovaAffiliated withDepartment of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston
  • , Ambro van HoofAffiliated withDepartment of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston

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Abstract

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.