5jea
Structure of a cytoplasmic 11-subunit RNA exosome complex including Ski7, bound to RNA
Structural highlights
FunctionRRP43_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. RRP43 is part of the hexameric ring of RNase PH domain-containing subunits proposed to form a central channel which threads RNA substrates for degradation.[1] [2] [3] [4] Publication Abstract from PubMedThe RNA exosome complex associates with nuclear and cytoplasmic cofactors to mediate the decay, surveillance, or processing of a wide variety of transcripts. In the cytoplasm, the conserved core of the exosome (Exo10) functions together with the conserved Ski complex. The interaction of S. cerevisiae Exo10 and Ski is not direct but requires a bridging cofactor, Ski7. Here, we report the 2.65 A resolution structure of S. cerevisiae Exo10 bound to the interacting domain of Ski7. Extensive hydrophobic interactions rationalize the high affinity and stability of this complex, pointing to Ski7 as a constitutive component of the cytosolic exosome. Despite the absence of sequence homology, cytoplasmic Ski7 and nuclear Rrp6 bind Exo10 using similar surfaces and recognition motifs. Knowledge of the interacting residues in the yeast complexes allowed us to identify a splice variant of human HBS1-Like as a Ski7-like exosome-binding protein, revealing the evolutionary conservation of this cytoplasmic cofactor. Structure of a Cytoplasmic 11-Subunit RNA Exosome Complex.,Kowalinski E, Kogel A, Ebert J, Reichelt P, Stegmann E, Habermann B, Conti E Mol Cell. 2016 Jul 7;63(1):125-34. doi: 10.1016/j.molcel.2016.05.028. Epub 2016, Jun 23. PMID:27345150[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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