2m8d
From Proteopedia
Structure of SRSF1 RRM2 in complex with the RNA 5'-UGAAGGAC-3'
Structural highlights
Function[SRSF1_HUMAN] Plays a role in preventing exon skipping, ensuring the accuracy of splicing and regulating alternative splicing. Interacts with other spliceosomal components, via the RS domains, to form a bridge between the 5'- and 3'-splice site binding components, U1 snRNP and U2AF. Can stimulate binding of U1 snRNP to a 5'-splice site-containing pre-mRNA. Binds to purine-rich RNA sequences, either the octamer, 5'-RGAAGAAC-3' (r=A or G) or the decamers, AGGACAGAGC/AGGACGAAGC. Binds preferentially to the 5'-CGAGGCG-3' motif in vitro. Three copies of the octamer constitute a powerful splicing enhancer in vitro, the ASF/SF2 splicing enhancer (ASE) which can specifically activate ASE-dependent splicing. Isoform ASF-2 and isoform ASF-3 act as splicing repressors.[1] [2] Publication Abstract from PubMedSerine/arginine (SR) proteins, one of the major families of alternative-splicing regulators in Eukarya, have two types of RNA-recognition motifs (RRMs): a canonical RRM and a pseudo-RRM. Although pseudo-RRMs are crucial for activity of SR proteins, their mode of action was unknown. By solving the structure of the human SRSF1 pseudo-RRM bound to RNA, we discovered a very unusual and sequence-specific RNA-binding mode that is centered on one alpha-helix and does not involve the beta-sheet surface, which typically mediates RNA binding by RRMs. Remarkably, this mode of binding is conserved in all pseudo-RRMs tested. Furthermore, the isolated pseudo-RRM is sufficient to regulate splicing of about half of the SRSF1 target genes tested, and the bound alpha-helix is a pivotal element for this function. Our results strongly suggest that SR proteins with a pseudo-RRM frequently regulate splicing by competing with, rather than recruiting, spliceosome components, using solely this unusual RRM. Isolated pseudo-RNA-recognition motifs of SR proteins can regulate splicing using a noncanonical mode of RNA recognition.,Clery A, Sinha R, Anczukow O, Corrionero A, Moursy A, Daubner GM, Valcarcel J, Krainer AR, Allain FH Proc Natl Acad Sci U S A. 2013 Jul 23;110(30):E2802-11. doi:, 10.1073/pnas.1303445110. Epub 2013 Jul 8. PMID:23836656[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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