This gene encodes a protein that is part of a post-splicing multiprotein complex involved in both mRNA nuclear export and mRNA surveillance. mRNA surveillance detects exported mRNAs with truncated open reading frames and initiates nonsense-mediated mRNA decay (NMD). When translation ends upstream from the last exon-exon junction, this triggers NMD to degrade mRNAs containing premature stop codons. This protein binds to the mRNA and remains bound after nuclear export, acting as a nucleocytoplasmic shuttling protein. This protein contains many serine residues. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Nov 2013]
Function:
Component of a splicing-dependent multiprotein exon junction complex (EJC) deposited at splice junction on mRNAs. The EJC is a dynamic structure consisting of a few core proteins and several more peripheral nuclear and cytoplasmic associated factors that join the complex only transiently either during EJC assembly or during subsequent mRNA metabolism. Part of pre- and post-splicing multiprotein mRNP complexes. Enhances the formation of the ATP-dependent A complex of the spliceosome. Involved in both constitutive splicing and, in association with SRP54 and TRA2B/SFRS10, in distinctive modulation of alternative splicing in a substrate-dependent manner. Participates in mRNA 3'-end cleavage. Involved in UPF2-dependent nonsense-mediated decay (NMD) of mRNAs containing premature stop codons. Also mediates increase of mRNA abundance and translational efficiency. Binds spliced mRNA 20-25 nt upstream of exon-exon junctions.
Subcellular Location:
Nucleus. Nucleus speckle. Cytoplasm. Nucleocytoplasmic shuttling protein. Colocalizes with the core EJC, ALYREF/THOC4, NXF1 and UAP56 in the nucleus and nuclear speckles.
Tissue Specificity:
Ubiquitous.
Post-translational modifications:
Phosphorylated on one or more of the four Ser/Thr residues (Ser-43, Thr-49, Ser-52 or Ser-53). Ser-53 phosphorylation site is important for splicing and translation stimulation activity in vitro.
Similarity:
Belongs to the splicing factor SR family.
Contains 1 RRM (RNA recognition motif) domain.
SWISS:
Q15287
Gene ID:
10921
Database links:
Entrez Gene: 10921 Human
Entrez Gene: 19826 Mouse
Entrez Gene: 287113 Rat
Omim: 606447 Human
SwissProt: Q15287 Human
SwissProt: Q99M28 Mouse
SwissProt: Q6AYK1 Rat
Unigene: 355643 Human
Unigene: 507343 Human
Unigene: 733012 Human
Unigene: 1951 Mouse
Unigene: 7235 Rat
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