title: Biochemistry and Function of RNA Exosomes.
abstract: Discovery of the evolutionary conserved RNA exosome was a milestone in RNA biology. First identified as an activity essential for the processing of ribosomal RNA, the exosome has since proved to be central for RNA processing and degradation in both the nucleus and the cytoplasm of eukaryotic cells. This multisubunit protein complex consists of a catalytically inert 9-subunit core endowed with associated ribonucleolytic activities and further assisted by compartment-specific cofactors required for its activation and substrate targeting. Although many features of exosome biology are known, fundamental aspects are still under investigation. In this chapter, we review current biochemical and functional knowledge of eukaryotic exosomes. After introducing some of their nuclear and cytoplasmic functions, we discuss the structural organization and evolutionary aspects of exosome complexes. Finally, we describe catalytic properties of the complex and its regulation by cofactors.
authors.affiliation: Department of Molecular Biology and Genetics, Centre for mRNP Biogenesis and Metabolism, Aarhus University, C.F. Møllers Allé 3, Aarhus C, Denmark; Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5a, Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5a, Warsaw, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Lubas
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5a, Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5a, Warsaw, Poland.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Chlebowski
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawińskiego 5a, Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, ul. Pawińskiego 5a, Warsaw, Poland. Electronic address: andrzejd@ibb.waw.pl.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Dziembowski
authors.affiliation: Department of Molecular Biology and Genetics, Centre for mRNP Biogenesis and Metabolism, Aarhus University, C.F. Møllers Allé 3, Aarhus C, Denmark. Electronic address: thj@mb.au.dk.
authors.forename: Torben Heick
authors.initials: TH
authors.lastname: Jensen
keywords: Exosome; RNA degradation; RNA processing; Ribonuclease