4oo1
From Proteopedia
Structure of an Rrp6-RNA exosome complex bound to poly(A) RNA
Structural highlights
FunctionCSL4_YEAST 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 cryptic unstable transcripts (CUTs), and of mRNAs with processing defects, thereby limiting or excluding their export to the cytoplasm. In the cytoplasm, the RNA exosome complex is involved in general mRNA turnover and in RNA surveillance pathways, preventing translation of aberrant mRNAs. 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.[1] [2] [3] Publication Abstract from PubMedThe eukaryotic RNA exosome processes and degrades RNA by directing substrates to the distributive or processive 3' to 5' exoribonuclease activities of Rrp6 or Rrp44, respectively. The non-catalytic nine-subunit exosome core (Exo9) features a prominent central channel. Although RNA can pass through the channel to engage Rrp44, it is not clear how RNA is directed to Rrp6 or whether Rrp6 uses the central channel. Here we report a 3.3 A crystal structure of a ten-subunit RNA exosome complex from Saccharomyces cerevisiae composed of the Exo9 core and Rrp6 bound to single-stranded poly(A) RNA. The Rrp6 catalytic domain rests on top of the Exo9 S1/KH ring above the central channel, the RNA 3' end is anchored in the Rrp6 active site, and the remaining RNA traverses the S1/KH ring in an opposite orientation to that observed in a structure of a Rrp44-containing exosome complex. Solution studies with human and yeast RNA exosome complexes suggest that the RNA path to Rrp6 is conserved and dependent on the integrity of the S1/KH ring. Although path selection to Rrp6 or Rrp44 is stochastic in vitro, the fate of a particular RNA may be determined in vivo by the manner in which cofactors present RNA to the RNA exosome. Structure of an Rrp6-RNA exosome complex bound to poly(A) RNA.,Wasmuth EV, Januszyk K, Lima CD Nature. 2014 Jul 24;511(7510):435-9. doi: 10.1038/nature13406. Epub 2014 Jul 6. PMID:25043052[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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