6d6q

Structural highlights

Function

EXOS9_HUMAN Non-catalytic component of the RNA exosome complex which has 3'->5' exoribonuclease activity and participates in a multitude of cellular RNA processing and degradation events. In the nucleus, the RNA exosome complex is involved in proper maturation of stable RNA species such as rRNA, snRNA and snoRNA, in the elimination of RNA processing by-products and non-coding 'pervasive' transcripts, such as antisense RNA species and promoter-upstream transcripts (PROMPTs), and of mRNAs with processing defects, thereby limiting or excluding their export to the cytoplasm. The RNA exosome may be involved in Ig class switch recombination (CSR) and/or Ig variable region somatic hypermutation (SHM) by targeting AICDA deamination activity to transcribed dsDNA substrates. In the cytoplasm, the RNA exosome complex is involved in general mRNA turnover and specifically degrades inherently unstable mRNAs containing AU-rich elements (AREs) within their 3' untranslated regions, and in RNA surveillance pathways, preventing translation of aberrant mRNAs. It seems to be involved in degradation of histone mRNA. The catalytic inactive RNA exosome core complex of 9 subunits (Exo-9) is proposed to play a pivotal role in the binding and presentation of RNA for ribonucleolysis, and to serve as a scaffold for the association with catalytic subunits and accessory proteins or complexes. EXOSC9 binds to ARE-containing RNAs.^{[1] [2] [3] [4]}

See Also

• Exosome 3D structures
• Helicase 3D structures

References

1. ↑ Mukherjee D, Gao M, O'Connor JP, Raijmakers R, Pruijn G, Lutz CS, Wilusz J. The mammalian exosome mediates the efficient degradation of mRNAs that contain AU-rich elements. EMBO J. 2002 Jan 15;21(1-2):165-74. PMID:11782436 doi:10.1093/emboj/21.1.165
2. ↑ West S, Gromak N, Norbury CJ, Proudfoot NJ. Adenylation and exosome-mediated degradation of cotranscriptionally cleaved pre-messenger RNA in human cells. Mol Cell. 2006 Feb 3;21(3):437-43. PMID:16455498 doi:http://dx.doi.org/10.1016/j.molcel.2005.12.008
3. ↑ Anderson JR, Mukherjee D, Muthukumaraswamy K, Moraes KC, Wilusz CJ, Wilusz J. Sequence-specific RNA binding mediated by the RNase PH domain of components of the exosome. RNA. 2006 Oct;12(10):1810-6. Epub 2006 Aug 15. PMID:16912217 doi:10.1261/rna.144606
4. ↑ van Dijk EL, Schilders G, Pruijn GJ. Human cell growth requires a functional cytoplasmic exosome, which is involved in various mRNA decay pathways. RNA. 2007 Jul;13(7):1027-35. Epub 2007 Jun 1. PMID:17545563 doi:10.1261/rna.575107