RBM8A

This gene encodes a protein with a conserved RNA-binding motif. The protein is found predominantly in the nucleus, although it is also present in the cytoplasm. It is preferentially associated with mRNAs produced by splicing, including both nuclear mRNAs and newly exported cytoplasmic mRNAs. It is thought that the protein remains associated with spliced mRNAs as a tag to indicate where introns had been present, thus coupling pre- and post-mRNA splicing events. Previously, it was thought that two genes encode this protein, RBM8A and RBM8B; it is now thought that the RBM8B locus is a pseudogene. Two alternative start codons result in two forms of the protein, and this gene also uses multiple polyadenylation sites. [provided by RefSeq]

Full Name

RNA binding motif protein 8A

Function

Required for pre-mRNA splicing as component of the spliceosome (PubMed:28502770, PubMed:29301961).
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). The MAGOH-RBM8A heterodimer inhibits the ATPase activity of EIF4A3, thereby trapping the ATP-bound EJC core onto spliced mRNA in a stable conformation. The MAGOH-RBM8A heterodimer interacts with the EJC key regulator PYM1 leading to EJC disassembly in the cytoplasm and translation enhancement of EJC-bearing spliced mRNAs by recruiting them to the ribosomal 48S preinitiation complex. Its removal from cytoplasmic mRNAs requires translation initiation from EJC-bearing spliced mRNAs. Associates preferentially with mRNAs produced by splicing. Does not interact with pre-mRNAs, introns, or mRNAs produced from intronless cDNAs. Associates with both nuclear mRNAs and newly exported cytoplasmic mRNAs. The MAGOH-RBM8A heterodimer is a component of the nonsense mediated decay (NMD) pathway. Involved in the splicing modulation of BCL2L1/Bcl-X (and probably other apoptotic genes); specifically inhibits formation of proapoptotic isoforms such as Bcl-X(S); the function is different from the established EJC assembly.

Biological Process

Biological Process mRNA export from nucleus1 PublicationIC:ComplexPortal
Biological Process mRNA splicing, via spliceosomeManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process nuclear-transcribed mRNA catabolic process, nonsense-mediated decayManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process regulation of alternative mRNA splicing, via spliceosomeManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process regulation of mRNA processingManual Assertion Based On ExperimentIDA:ComplexPortal
Biological Process regulation of nuclear-transcribed mRNA catabolic process, nonsense-mediated decayManual Assertion Based On ExperimentIDA:ComplexPortal
Biological Process regulation of translationIEA:UniProtKB-KW
Biological Process RNA splicingManual Assertion Based On ExperimentIBA:GO_Central

Cellular Location

Nucleus
Nucleus speckle
Cytoplasm
Nucleocytoplasmic shuttling protein (PubMed:11030346).
Travels to the cytoplasm as part of the exon junction complex (EJC) bound to mRNA. Colocalizes with the core EJC, ALYREF/THOC4, NXF1 and UAP56 in the nucleus and nuclear speckles (PubMed:19324961).

Involvement in disease

Thrombocytopenia-absent radius syndrome (TAR):
An autosomal recessive disorder characterized by bilateral absence of the radii with the presence of both thumbs, thrombocytopenia, low numbers of megakaryocytes, and bleeding episodes in the first year of life. Thrombocytopenic episodes decrease with age. Skeletal anomalies range from absence of radii to virtual absence of upper limbs, with or without lower limb defects such as malformations of the hip and knee.