EIF4A3
EIF4A3 (eukaryotic translation initiation factor 4A3, also known as eIF4AIII, DDX48, Fal1 or KIAA0111) is an ATP-dependent RNA helicase of the DEAD-box family. It is a core component of the exon junction complex deposited on mRNAs during splicing. Browse Assay Genie's current range of EIF4A3 research reagents below, or read on for the biology behind the target.
EIF4A3 is an ATP-dependent RNA helicase involved in pre-mRNA splicing as a component of the spliceosome. It is a core component of the splicing-dependent multiprotein exon junction complex (EJC), which is deposited at splice junctions on mRNAs. The EJC marks the position of the exon-exon junction in the mature mRNA, and its core components remain bound to spliced mRNAs through all stages of mRNA metabolism. In this way the complex influences nuclear mRNA export, subcellular mRNA localisation, translation efficiency and nonsense-mediated mRNA decay (NMD).
The RNA-dependent ATPase and helicase activities of EIF4A3 are induced by CASC3 but abolished in the presence of the MAGOH-RBM8A heterodimer. This traps the ATP-bound EJC core on spliced mRNA in a stable conformation and increases the RNA-binding affinity of the EJC. EIF4A3 binds spliced mRNA in a sequence-independent manner, 20-24 nucleotides upstream of exon-exon junctions, and shows higher affinity for single-stranded RNA in the ATP-bound core EJC than after ATP hydrolysis. It is also involved in translational enhancement of spliced mRNAs after formation of the 80S ribosome complex. Separately from EJC assembly, it modulates splicing of BCL2L1/Bcl-X, and probably other apoptotic genes, by inhibiting formation of proapoptotic isoforms such as Bcl-X(S).
The EIF4A3 gene encodes a member of the DEAD box protein family, characterised by the conserved Asp-Glu-Ala-Asp motif, and belongs to the eIF4A subfamily. Its sequence is highly similar to the translation initiation factors eIF4AI and eIF4AII. It is a nuclear matrix protein found in the nucleus, nuclear speckles and cytoplasm, and is involved in craniofacial development. Previous names include DEAD (Asp-Glu-Ala-Asp) box polypeptide 48 and eukaryotic translation initiation factor 4A, isoform 3. Mouse and rat orthologues are both named Eif4a3.
EIF4A3 is a core EJC component that marks exon-exon junctions on spliced mRNAs and stays bound through downstream mRNA metabolism.
As a spliceosome component, EIF4A3 is studied for its role in pre-mRNA splicing, including modulation of BCL2L1/Bcl-X isoform formation.
EJC-bound EIF4A3 influences nonsense-mediated mRNA decay, alongside nuclear export, mRNA localisation and translation efficiency.
Its ATPase and helicase activities are regulated by CASC3 and the MAGOH-RBM8A heterodimer, making it a model for studying EJC locking onto RNA.
EIF4A3 is an ATP-dependent RNA helicase and a core component of the exon junction complex. It binds spliced mRNA upstream of exon-exon junctions and influences mRNA export, localisation, translation efficiency and nonsense-mediated decay. It also takes part in pre-mRNA splicing as a spliceosome component.
EIF4A3 is also called eIF4AIII, DDX48, Fal1 and KIAA0111. Earlier names were DEAD (Asp-Glu-Ala-Asp) box polypeptide 48 and eukaryotic translation initiation factor 4A, isoform 3. UniProt lists the protein as eukaryotic initiation factor 4A-III.
EIF4A3 is a DEAD-box protein of the eIF4A subfamily, and its amino acid sequence is highly similar to the translation initiation factors eIF4AI and eIF4AII. Unlike them, it functions mainly in the exon junction complex and splicing. Mouse and rat orthologues are named Eif4a3; check the datasheet of any product for its validated reactivity.
Other eIF4A family members, translation initiation factors and related RNA-processing targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P38919; product specifications from Assay Genie datasheets.