UPF3A
Description
The UPF3A (UPF3A regulator of nonsense mediated mRNA decay) is a protein-coding gene located on chromosome 13.
UPF3A is a protein encoded by the UPF3A gene in humans. It's part of a multiprotein complex involved in both mRNA nuclear export and mRNA surveillance, specifically nonsense-mediated mRNA decay (NMD). NMD degrades mRNAs with premature stop codons. When translation ends before the last exon-exon junction, NMD is triggered. UPF3A binds to the mRNA and remains bound after nuclear export, acting as a nucleocytoplasmic shuttling protein. It forms a complex with RBM8A that specifically binds 20 nucleotides upstream of exon-exon junctions. The UPF3A gene is located on the long arm of chromosome 13. Two splice variants encoding different isoforms have been found for this gene. UPF3A interacts with RBM8A, UPF2, and UPF1.
UPF3A plays a role in nonsense-mediated decay (NMD), a process that eliminates mRNAs containing premature stop codons. It associates with the nuclear exon junction complex (EJC) and acts as a link between the EJC core and the NMD machinery. Specifically, it recruits UPF2 to the cytoplasmic side of the nuclear envelope, contributing to the formation of the UPF1-UPF2-UPF3 surveillance complex, which is believed to initiate NMD. However, UPF3A's activity in NMD is relatively weak compared to its counterpart, UPF3B. In addition to its role in NMD, UPF3A binds to spliced mRNA upstream of exon-exon junctions. In vitro studies have shown that it weakly stimulates translation.
UPF3A is also known as HUPF3A, RENT3A, UPF3.
