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PMID: 22961380 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

Human CWC22 escorts the helicase eIF4AIII to spliceosomes and promotes exon junction complex assembly.

Nature structural & molecular biology ·Vol. 19 ·No. 10 ·2012-10-00 ·Pages 983-90

Barbosa I, Haque N, Fiorini F, Barrandon C, Tomasetto C, Blanchette M, Le Hir H

Abstract

The exon-junction complex (EJC) functionally links splicing to subsequent mRNA localization, translation and stability. Sequence-independent binding of the EJC core to RNA is ensured by the DEAD-box helicase eIF4AIII. Here, we identified the splicing factor CWC22 as a new eIF4AIII partner in flies and humans. CWC22 coexists with eIF4AIII in large protein complexes distinct from EJCs. Recombinant CWC22 directly contacts eIF4AIII and prevents it from binding RNA. In vitro splicing assays revealed that CWC22 introduces eIF4AIII to spliceosomes before remodeling to facilitate eIF4AIII incorporation into the EJC. Finally, using knockdowns in vivo, we showed that CWC22 is essential for EJC assembly. We elucidated the initial step of EJC assembly and the duality of CWC22 function that hinders eIF4AIII from nonspecifically binding RNA and escorts it to the splicing machinery to promote EJC assembly on mature mRNAs.

MeSH Terms
Amino Acid Sequence Animals Carrier Proteins/genetics,metabolism DEAD-box RNA Helicases/genetics,metabolism DNA Repair Enzymes/genetics,metabolism Eukaryotic Initiation Factor-4A/genetics,metabolism Exons Gene Knockdown Techniques Humans Molecular Sequence Data Nuclear Proteins/genetics,metabolism Peptidylprolyl Isomerase Protein Interaction Domains and Motifs Protein Structure, Tertiary RNA/metabolism RNA Splicing RNA Splicing Factors RNA, Messenger/metabolism RNA-Binding Proteins Recombinant Proteins/genetics,metabolism Spliceosomes/metabolism
Chemicals
CWC22 protein, human Carrier Proteins Nuclear Proteins RNA Splicing Factors RNA, Messenger RNA-Binding Proteins Recombinant Proteins RNA Eukaryotic Initiation Factor-4A EIF4A3 protein, human DEAD-box RNA Helicases Peptidylprolyl Isomerase DNA Repair Enzymes PRPF19 protein, human
Authors & Affiliations
7 authors, click to expand affiliations / ORCID
Barbosa Isabelle
Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique UMR8197, Paris, France.
Haque Nazmul
Fiorini Francesca
Barrandon Charlotte
Tomasetto Catherine
Blanchette Marco
Le Hir Hervé
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Article Info
Journal
Nature structural & molecular biology
Abbr.
Nat Struct Mol Biol
ISSN
1545-9985
DOI
10.1038/nsmb.2380
Published
2012-10-00
Epub
2012-00-09
Pages
983-90
Language
English
Region
United States
NLM ID
101186374
Subset
IM
External Links
PubMed source DOI: 10.1038/nsmb.2380 View journal details
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