3sag

Structural highlights

Function

EXOSX_HUMAN Putative 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. EXOSC10 has 3'-5' exonuclease activity (By similarity). EXOSC10 is required for nucleolar localization of C1D and probably mediates the association of SKIV2L2, C1D and MPP6 wth the RNA exosome involved in the maturation of 5.8S rRNA.^{[1] [2] [3] [4] [5] [6] [7] [8]}

See Also

• Exosome 3D structures

References

1. ↑ Lejeune F, Li X, Maquat LE. Nonsense-mediated mRNA decay in mammalian cells involves decapping, deadenylating, and exonucleolytic activities. Mol Cell. 2003 Sep;12(3):675-87. PMID:14527413
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. ↑ Schilders G, van Dijk E, Pruijn GJ. C1D and hMtr4p associate with the human exosome subunit PM/Scl-100 and are involved in pre-rRNA processing. Nucleic Acids Res. 2007;35(8):2564-72. Epub 2007 Apr 4. PMID:17412707 doi:http://dx.doi.org/10.1093/nar/gkm082
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
5. ↑ Mullen TE, Marzluff WF. Degradation of histone mRNA requires oligouridylation followed by decapping and simultaneous degradation of the mRNA both 5' to 3' and 3' to 5'. Genes Dev. 2008 Jan 1;22(1):50-65. doi: 10.1101/gad.1622708. PMID:18172165 doi:10.1101/gad.1622708
6. ↑ Preker P, Nielsen J, Kammler S, Lykke-Andersen S, Christensen MS, Mapendano CK, Schierup MH, Jensen TH. RNA exosome depletion reveals transcription upstream of active human promoters. Science. 2008 Dec 19;322(5909):1851-4. doi: 10.1126/science.1164096. Epub 2008, Dec 4. PMID:19056938 doi:10.1126/science.1164096
7. ↑ de Almeida SF, Garcia-Sacristan A, Custodio N, Carmo-Fonseca M. A link between nuclear RNA surveillance, the human exosome and RNA polymerase II transcriptional termination. Nucleic Acids Res. 2010 Dec;38(22):8015-26. doi: 10.1093/nar/gkq703. Epub 2010, Aug 10. PMID:20699273 doi:http://dx.doi.org/10.1093/nar/gkq703
8. ↑ Slomovic S, Fremder E, Staals RH, Pruijn GJ, Schuster G. Addition of poly(A) and poly(A)-rich tails during RNA degradation in the cytoplasm of human cells. Proc Natl Acad Sci U S A. 2010 Apr 20;107(16):7407-12. doi:, 10.1073/pnas.0910621107. Epub 2010 Apr 5. PMID:20368444 doi:10.1073/pnas.0910621107