Structural basis for the recognition of spliceosomal SmN/B/B’ proteins by the RBM5 OCRE domain in splicing regulation
André Mourão,
Sophie Bonnal,
Komal Soni,
Lisa Warner,
Rémy Bordonné,
Juan Valcárcel,
Michael Sattler
Affiliations
André Mourão
Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
Sophie Bonnal
Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Centre de Regulació Genòmica, Barcelona, Spain
Komal Soni
Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
Lisa Warner
Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
Rémy Bordonné
Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université de Montpellier, Montpellier, France
Juan Valcárcel
Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Centre de Regulació Genòmica, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany; Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
The multi-domain splicing factor RBM5 regulates the balance between antagonistic isoforms of the apoptosis-control genes FAS/CD95, Caspase-2 and AID. An OCRE (OCtamer REpeat of aromatic residues) domain found in RBM5 is important for alternative splicing regulation and mediates interactions with components of the U4/U6.U5 tri-snRNP. We show that the RBM5 OCRE domain adopts a unique β–sheet fold. NMR and biochemical experiments demonstrate that the OCRE domain directly binds to the proline-rich C-terminal tail of the essential snRNP core proteins SmN/B/B’. The NMR structure of an OCRE-SmN peptide complex reveals a specific recognition of poly-proline helical motifs in SmN/B/B’. Mutation of conserved aromatic residues impairs binding to the Sm proteins in vitro and compromises RBM5-mediated alternative splicing regulation of FAS/CD95. Thus, RBM5 OCRE represents a poly-proline recognition domain that mediates critical interactions with the C-terminal tail of the spliceosomal SmN/B/B’ proteins in FAS/CD95 alternative splicing regulation.
