UniProt ID: Q7ZVA6
FUNCTION: ATP-dependent RNA helicase. Involved in pre-mRNA splicing as component of the spliceosome. Core component of the splicing-dependent multiprotein exon junction complex (EJC) deposited at splice junctions on mRNAs. The EJC is a dynamic structure consisting of core proteins and several peripheral nuclear and cytoplasmic associated factors that join the complex only transiently either during EJC assembly or during subsequent mRNA metabolism. The EJC marks the position of the exon-exon junction in the mature mRNA for the gene expression machinery and the core components remain bound to spliced mRNAs throughout all stages of mRNA metabolism thereby influencing downstream processes including nuclear mRNA export, subcellular mRNA localization, translation efficiency and nonsense-mediated mRNA decay (NMD). Binds spliced mRNA in sequence-independent manner, 20-24 nucleotides upstream of mRNA exon-exon junctions (By similarity). Involved in craniofacial development (PubMed:24360810). {ECO:0000250|UniProtKB:P38919, ECO:0000269|PubMed:24360810}.
CATALYTIC ACTIVITY: Reaction=ATP + H2O = ADP + H(+) + phosphate; Xref=Rhea:RHEA:13065, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:456216; EC=; Evidence={ECO:0000250|UniProtKB:P38919};
SUBUNIT: Identified in the spliceosome C complex. Part of the mRNA splicing-dependent exon junction complex (EJC) complex; the core complex contains casc3, eif4a3, magoh and rbm8a. {ECO:0000250|UniProtKB:P38919}.
SUBCELLULAR LOCATION: Nucleus {ECO:0000250|UniProtKB:Q3B8Q2}. Nucleus speckle {ECO:0000250|UniProtKB:P38919}. Cytoplasm {ECO:0000250|UniProtKB:Q3B8Q2}. Note=Nucleocytoplasmic shuttling protein. Travels to the cytoplasm as part of the exon junction complex (EJC) bound to mRNA. {ECO:0000250|UniProtKB:Q3B8Q2}.
DISRUPTION PHENOTYPE: Morpholino EIF4A3 knockdown results in multiple defects in craniofacial structures. Fish morphants staged at 24 hpf show eyes reduced in size, and dark and opaque zones in all brain structures. In addition, the otic vesicle and the midbrain/hindbrain border regions are barely detectable. Cartilage and bone staining reveals underdevelopment of craniofacial cartilage, bone alterations, and clefting of the lower jaw. The third through sixth pharyngeal arches are underdeveloped in morphants. {ECO:0000269|PubMed:24360810}.
SIMILARITY: Belongs to the DEAD box helicase family. eIF4A subfamily. {ECO:0000305}.
UniProt ID: B2GTC1
SIMILARITY: Belongs to the DEAD box helicase family. {ECO:0000256|RuleBase:RU000492}.
UniProt ID: A0A0R4IKW3
SIMILARITY: Belongs to the DEAD box helicase family. {ECO:0000256|RuleBase:RU000492}.
This information was provided by UniProt through a collaboration with ZFIN. (1)