| Structural highlights
Function
BRR2_YEAST RNA helicase that plays an essential role in pre-mRNA splicing as component of the U5 snRNP and U4/U6-U5 tri-snRNP complexes. Involved in spliceosome assembly, activation and disassembly. Mediates changes in the dynamic network of RNA-RNA interactions in the spliceosome. Catalyzes the ATP-dependent unwinding of U4/U6 RNA duplices, an essential step in the assembly of a catalytically active spliceosome.[1] [2] [3] [4]
Publication Abstract from PubMed
The Brr2 helicase provides the key remodeling activity for spliceosome catalytic activation, during which it disrupts the U4/U6 di-snRNP (small nuclear RNA protein), and its activity has to be tightly regulated. Brr2 exhibits an unusual architecture, including an approximately 500-residue N-terminal region, whose functions and molecular mechanisms are presently unknown, followed by a tandem array of structurally similar helicase units (cassettes), only the first of which is catalytically active. Here, we show by crystal structure analysis of full-length Brr2 in complex with a regulatory Jab1/MPN domain of the Prp8 protein and by cross-linking/mass spectrometry of isolated Brr2 that the Brr2 N-terminal region encompasses two folded domains and adjacent linear elements that clamp and interconnect the helicase cassettes. Stepwise N-terminal truncations led to yeast growth and splicing defects, reduced Brr2 association with U4/U6*U5 tri-snRNPs, and increased ATP-dependent disruption of the tri-snRNP, yielding U4/U6 di-snRNP and U5 snRNP. Trends in the RNA-binding, ATPase, and helicase activities of the Brr2 truncation variants are fully rationalized by the crystal structure, demonstrating that the N-terminal region autoinhibits Brr2 via substrate competition and conformational clamping. Our results reveal molecular mechanisms that prevent premature and unproductive tri-snRNP disruption and suggest novel principles of Brr2-dependent splicing regulation.
The large N-terminal region of the Brr2 RNA helicase guides productive spliceosome activation.,Absmeier E, Wollenhaupt J, Mozaffari-Jovin S, Becke C, Lee CT, Preussner M, Heyd F, Urlaub H, Luhrmann R, Santos KF, Wahl MC Genes Dev. 2015 Dec 4. PMID:26637280[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Maeder C, Kutach AK, Guthrie C. ATP-dependent unwinding of U4/U6 snRNAs by the Brr2 helicase requires the C terminus of Prp8. Nat Struct Mol Biol. 2009 Jan;16(1):42-8. doi: 10.1038/nsmb.1535. Epub 2008 Dec, 21. PMID:19098916 doi:http://dx.doi.org/10.1038/nsmb.1535
- ↑ Hahn D, Kudla G, Tollervey D, Beggs JD. Brr2p-mediated conformational rearrangements in the spliceosome during activation and substrate repositioning. Genes Dev. 2012 Nov 1;26(21):2408-21. doi: 10.1101/gad.199307.112. PMID:23124065 doi:http://dx.doi.org/10.1101/gad.199307.112
- ↑ Pena V, Jovin SM, Fabrizio P, Orlowski J, Bujnicki JM, Luhrmann R, Wahl MC. Common design principles in the spliceosomal RNA helicase Brr2 and in the Hel308 DNA helicase. Mol Cell. 2009 Aug 28;35(4):454-66. PMID:19716790 doi:10.1016/j.molcel.2009.08.006
- ↑ Zhang L, Xu T, Maeder C, Bud LO, Shanks J, Nix J, Guthrie C, Pleiss JA, Zhao R. Structural evidence for consecutive Hel308-like modules in the spliceosomal ATPase Brr2. Nat Struct Mol Biol. 2009 Jul;16(7):731-9. Epub 2009 Jun 14. PMID:19525970 doi:10.1038/nsmb.1625
- ↑ Absmeier E, Wollenhaupt J, Mozaffari-Jovin S, Becke C, Lee CT, Preussner M, Heyd F, Urlaub H, Luhrmann R, Santos KF, Wahl MC. The large N-terminal region of the Brr2 RNA helicase guides productive spliceosome activation. Genes Dev. 2015 Dec 4. PMID:26637280 doi:http://dx.doi.org/10.1101/gad.271528.115
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