| Structural highlights
Function
[MTR4_YEAST] ATP-dependent RNA helicase required for the 3'-end formation of 5.8S RNA. Cofactor for the exosome complex that unwinds secondary structure in pre-rRNA. Required for nucleocytoplasmic transport of mRNA. May serve as a chaperone which translocates or normalizes the structure of mRNAs in preparation for export. Component of the TRAMP complex which has a poly(A) RNA polymerase activity and is involved in a post-transcriptional quality control mechanism limiting inappropriate expression of genetic information. Polyadenylation is required for the degradative activity of the exosome on several of its nuclear RNA substrates.[1] [NOP53_YEAST] Late-acting factor in the nuclear maturation of 60S ribosomal subunits, which is required for normal acquisition of export competence. Required for the export of the large subunit. Acts to stimulate the RNase activity of the exosome complex, and may recruit the exosome to 7S pre-rRNA for processing. Associates with numerous RNAs including the 27S and 7S pre-rRNAs and the box H/ACA snoRNA snR37. Also interacts (via N-terminal region) with the mature 25S rRNA and the mature 5.8S rRNA.[2] [3] [4] [5]
Publication Abstract from PubMed
The nuclear exosome and the associated RNA helicase Mtr4 participate in the processing of several ribonucleoprotein particles (RNP), including the maturation of the large ribosomal subunit (60S). S. cerevisiae Mtr4 interacts directly with Nop53, a ribosomal biogenesis factor present in late pre-60S particles containing precursors of the 5.8S rRNA. The Mtr4-Nop53 interaction plays a pivotal role in the maturation of the 5.8S rRNA, providing a physical link between the nuclear exosome and the pre-60S RNP. An analogous interaction between Mtr4 and another ribosome biogenesis factor, Utp18, directs the exosome to an earlier pre-ribosomal particle. Nop53 and Utp18 contain a similar Mtr4-binding motif known as the arch-interacting motif (AIM). Here, we report the 3.2 A resolution crystal structure of S.cerevisiae Mtr4 bound to the interacting region of Nop53, revealing how the KOW domain of the helicase recognizes the AIM sequence of Nop53 with a network of hydrophobic and electrostatic interactions. The AIM-interacting residues are conserved in Mtr4 and are not present in the related cytoplasmic helicase Ski2, rationalizing the specificity and versatility of Mtr4 in the recognition of different AIM-containing proteins. Using nuclear magnetic resonance (NMR), we show that the KOW domain of Mtr4 can simultaneously bind an AIM-containing protein and a structured RNA at adjacent surfaces, suggesting how it can dock onto RNPs. The KOW domains of exosome-associated helicases thus appear to have evolved from the KOW domains of ribosomal proteins and to function as RNP-binding modules in the context of the nuclear exosome.
Structural insights into the interaction of the nuclear exosome helicase Mtr4 with the pre-ribosomal protein Nop53.,Falk S, Tants JN, Basquin J, Thoms M, Hurt E, Sattler M, Conti E RNA. 2017 Sep 7. pii: rna.062901.117. doi: 10.1261/rna.062901.117. PMID:28883156[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Vanacova S, Wolf J, Martin G, Blank D, Dettwiler S, Friedlein A, Langen H, Keith G, Keller W. A new yeast poly(A) polymerase complex involved in RNA quality control. PLoS Biol. 2005 Jun;3(6):e189. Epub 2005 Apr 19. PMID:15828860 doi:http://dx.doi.org/05-PLBI-RA-0095R2
- ↑ Sydorskyy Y, Dilworth DJ, Halloran B, Yi EC, Makhnevych T, Wozniak RW, Aitchison JD. Nop53p is a novel nucleolar 60S ribosomal subunit biogenesis protein. Biochem J. 2005 Jun 15;388(Pt 3):819-26. PMID:15686447 doi:http://dx.doi.org/BJ20041297
- ↑ Thomson E, Tollervey D. Nop53p is required for late 60S ribosome subunit maturation and nuclear export in yeast. RNA. 2005 Aug;11(8):1215-24. PMID:16043506 doi:http://dx.doi.org/10.1261/rna.2720205
- ↑ Granato DC, Gonzales FA, Luz JS, Cassiola F, Machado-Santelli GM, Oliveira CC. Nop53p, an essential nucleolar protein that interacts with Nop17p and Nip7p, is required for pre-rRNA processing in Saccharomyces cerevisiae. FEBS J. 2005 Sep;272(17):4450-63. PMID:16128814 doi:http://dx.doi.org/10.1111/j.1742-4658.2005.04861.x
- ↑ Granato DC, Machado-Santelli GM, Oliveira CC. Nop53p interacts with 5.8S rRNA co-transcriptionally, and regulates processing of pre-rRNA by the exosome. FEBS J. 2008 Aug;275(16):4164-78. doi: 10.1111/j.1742-4658.2008.06565.x. Epub, 2008 Jul 9. PMID:18631361 doi:http://dx.doi.org/10.1111/j.1742-4658.2008.06565.x
- ↑ Falk S, Tants JN, Basquin J, Thoms M, Hurt E, Sattler M, Conti E. Structural insights into the interaction of the nuclear exosome helicase Mtr4 with the pre-ribosomal protein Nop53. RNA. 2017 Sep 7. pii: rna.062901.117. doi: 10.1261/rna.062901.117. PMID:28883156 doi:http://dx.doi.org/10.1261/rna.062901.117
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