An autoinhibitory intramolecular interaction proof-reads RNA recognition by the essential splicing factor U2AF2

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 117; no. 13; pp. 7140 - 7149
• Main Authors: Kang, Hyun-Seo, Sánchez-Rico, Carolina, Ebersberger, Stefanie, Sutandy, F X Reymond, Busch, Anke, Welte, Thomas, Stehle, Ralf, Hipp, Clara, Schulz, Laura, Buchbender, Andreas, Zarnack, Kathi, König, Julian, Sattler, Michael
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 31.03.2020
• Subjects: Binding; Biological Sciences; Gene expression; Gene regulation; Mutation; NMR; Nuclear magnetic resonance; Proofreading; Recognition; Regulatory mechanisms (biology); Ribonucleic acid; RNA; RNA-binding protein; Splicing; Splicing factors; structural biology; splicing; protein–RNA interactions; iCLIP; U2 auxiliary factor
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1913483117

The recognition of -regulatory RNA motifs in human transcripts by RNA binding proteins (RBPs) is essential for gene regulation. The molecular features that determine RBP specificity are often poorly understood. Here, we combined NMR structural biology with high-throughput iCLIP approaches to identify a regulatory mechanism for U2AF2 RNA recognition. We found that the intrinsically disordered linker region connecting the two RNA recognition motif (RRM) domains of U2AF2 mediates autoinhibitory intramolecular interactions to reduce nonproductive binding to weak Py-tract RNAs. This proofreading favors binding of U2AF2 at stronger Py-tracts, as required to define 3' splice sites at early stages of spliceosome assembly. Mutations that impair the linker autoinhibition enhance the affinity for weak Py-tracts result in promiscuous binding of U2AF2 along mRNAs and impact on splicing fidelity. Our findings highlight an important role of intrinsically disordered linkers to modulate RNA interactions of multidomain RBPs.