Recombinant Human Regulator of nonsense transcripts 3B (UPF3B)

Uniprot Id

Q9BZI7

Target Species

Human

Target Name

UPF3B

Target Full Name

Regulator of nonsense transcripts 3B

Target Function

Involved in nonsense-mediated decay (NMD) of mRNAs containing premature stop codons by associating with the nuclear exon junction complex (EJC) and serving as link between the EJC core and NMD machinery. Recruits UPF2 at the cytoplasmic side of the nuclear envelope and the subsequent formation of an UPF1-UPF2-UPF3 surveillance complex (including UPF1 bound to release factors at the stalled ribosome) is believed to activate NMD. In cooperation with UPF2 stimulates both ATPase and RNA helicase activities of UPF1. Binds spliced mRNA upstream of exon-exon junctions. In vitro, stimulates translation; the function is independent of association with UPF2 and components of the EJC core.

Target Involvement

Mental retardation, X-linked, syndromic, 14 (MRXS14)

Target Subcellular Location

Nucleus. Cytoplasm. Note=Shuttling between the nucleus and the cytoplasm.

Target Protein Families

RENT3 family

Target Tissue Specificity

Expressed in testis, uterus, prostate, heart, muscle, brain, spinal cord and placenta.

Target Synonyms

UPF3B; RENT3B; UPF3X; Regulator of nonsense transcripts 3B; Nonsense mRNA reducing factor 3B; Up-frameshift suppressor 3 homolog B; hUpf3B; Up-frameshift suppressor 3 homolog on chromosome X; hUpf3p-X

Target Background

This gene encodes a protein that is part of a post-splicing multiprotein complex involved in both mRNA nuclear export and mRNA surveillance. The encoded protein is one of two functional homologs to yeast Upf3p. 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. It forms with Y14 a complex that binds specifically 20 nt upstream of exon-exon junctions. This gene is located on the long arm of chromosome X. Two splice variants encoding different isoforms have been found for this gene.