5gap
From Proteopedia
Body region of the U4/U6.U5 tri-snRNP
Structural highlights
Function[PRP4_YEAST] Involved in RNA splicing. Is required for the association of U4/U6 snRNP with U5 snRNP in an early step of spliceosome assembly. [SNU13_YEAST] Common component of the spliceosome and rRNA processing machinery. In association with the spliceosomal U4/U6.U5 tri-snRNP particle, required for splicing of pre-mRNA. In association with box C/D snoRNPs, required for processing of pre-ribosomal RNA (rRNA) and site-specific 2'-O-methylation of substrate RNAs. Essential for the accumulation and stability of U4 snRNA, U6 snRNA, and box C/D snoRNAs.[1] [2] [3] [PRP6_YEAST] Participates in pre-mRNA splicing. Part of the U4/U5/U6 tri-snRNP complex, one of the building blocks of the spliceosome. [PRP31_YEAST] Promotes the association of the U4/U6.U5 tri-snRNP particle with pre-spliceosomes to form the mature spliceosomal complex.[4] [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.[5] [6] [7] [8] [DIB1_YEAST] Essential role in pre-mRNA splicing. Also essential for entry into mitosis (G2/M progression) as well as for chromosome segregation during mitosis. [PRP3_YEAST] Participates in pre-mRNA splicing. Part of the U4/U5/U6 tri-snRNP complex, one of the building blocks of the spliceosome.[9] [PRP8_YEAST] Required for pre-spliceosome formation, which is the first step of pre-mRNA splicing. This protein is associated with snRNP U5. Has a role in branch site-3' splice site selection. Associates with the branch site-3' splice 3'-exon region. Also has a role in cell cycle.[10] [11] [12] [13] Publication Abstract from PubMedU4/U6.U5 tri-snRNP represents a substantial part of the spliceosome before activation. A cryo-electron microscopy structure of Saccharomyces cerevisiae U4/U6.U5 tri-snRNP at 3.7 A resolution led to an essentially complete atomic model comprising 30 proteins plus U4/U6 and U5 small nuclear RNAs (snRNAs). The structure reveals striking interweaving interactions of the protein and RNA components, including extended polypeptides penetrating into subunit interfaces. The invariant ACAGAGA sequence of U6 snRNA, which base-pairs with the 5'-splice site during catalytic activation, forms a hairpin stabilized by Dib1 and Prp8 while the adjacent nucleotides interact with the exon binding loop 1 of U5 snRNA. Snu114 harbours GTP, but its putative catalytic histidine is held away from the gamma-phosphate by hydrogen bonding to a tyrosine in the amino-terminal domain of Prp8. Mutation of this histidine to alanine has no detectable effect on yeast growth. The structure provides important new insights into the spliceosome activation process leading to the formation of the catalytic centre. Cryo-EM structure of the yeast U4/U6.U5 tri-snRNP at 3.7 A resolution.,Nguyen TH, Galej WP, Bai XC, Oubridge C, Newman AJ, Scheres SH, Nagai K Nature. 2016 Feb 18;530(7590):298-302. doi: 10.1038/nature16940. Epub 2016 Feb 1. PMID:26829225[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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