UPF1 Antibody – Rabbit Polyclonal

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 is located only in the cytoplasm. When translation ends, it interacts with the protein that is a functional homolog of yeast Upf2p to trigger mRNA decapping. Use of multiple polyadenylation sites has been noted for this gene. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

RENT1: RNA-dependent helicase and ATPase required for nonsense- mediated decay (NMD) of mRNAs containing premature stop codons. Is recruited to mRNAs upon translation termination and undergoes a cycle of phosphorylation and dephosphorylation; its phosphorylation appears to be a key step in NMD. Recruited by release factors to stalled ribosomes together with the SMG1C protein kinase complex to form the transient SURF (SMG1-UPF1-eRF1- eRF3) complex. In EJC-dependent NMD, the SURF complex associates with the exon junction complex (EJC) (located 50-55 or more nucleotides downstream from the termination codon) through UPF2 and allows the formation of an UPF1-UPF2-UPF3 surveillance complex which is believed to activate NMD. Phosphorylated UPF1 is recognized by EST1B/SMG5, SMG6 and SMG7 which are thought to provide a link to the mRNA degradation machinery involving exonucleolytic and endonucleolytic pathways, and to serve as adapters to protein phosphatase 2A (PP2A), thereby triggering UPF1 dephosphorylation and allowing the recycling of NMD factors. UPF1 can also activate NMD without UPF2 or UPF3, and in the absence of the NMD-enhancing downstream EJC indicative for alternative NMD pathways. Plays a role in replication-dependent histone mRNA degradation at the end of phase S; the function is independent of UPF2. For the recognition of premature termination codons (PTC) and initiation of NMD a competitive interaction between UPF1 and PABPC1 with the ribosome-bound release factors is proposed. The ATPase activity of UPF1 is required for disassembly of mRNPs undergoing NMD. Essential for embryonic viability. Found in a post-splicing messenger ribonucleoprotein (mRNP) complex. Associates with the exon junction complex (EJC). Associates with the SGM1C complex; is phosphorylated by the complex kinase component SGM1. Interacts with UPF2, UPF3A and UPF3B. Interacts with EST1A and SLBP. Interacts (when hyperphosphorylated) with PNRC2. Interacts with EIF2C1, EIF2C2 and GSPT2. Ubiquitous. Belongs to the DNA2/NAM7 helicase family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: RNA-binding; C2H2-type zinc finger protein; EC 3.6.4.-; Hydrolase; EC 3.6.1.-

Chromosomal Location of Human Ortholog: 19p13.11

Cellular Component: nucleoplasm; cytoplasm; cytosol; nucleus; chromatin

Molecular Function: protein binding; DNA binding; zinc ion binding; RNA binding; chromatin binding; helicase activity; ATP binding; ATP-dependent RNA helicase activity

Biological Process: mRNA export from nucleus; dosage compensation, by inactivation of X chromosome; mRNA catabolic process, nonsense-mediated decay; gene expression; DNA replication; DNA repair; regulation of translational termination