UPF1 - Regulator of nonsense transcripts 1 - human protein (Function)
 
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Protein
Gene
References

 
UPF1 »  Regulator of nonsense transcripts 1   [ EC 3.6.4.- ]
 
Protein also known as:  Up-frameshift suppressor 1 homolog.
Gene name:  UPF1
Family name: DNA2/NAM7 helicase
Entry whose protein(s) existence is based on evidence at protein level
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1 141 2
GENE REF ISO

Function

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Overview 
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.  
6
  • UniProtKB
GO molecular function 
ATP bindingdefinition[GO:0005524]  
1
  • UniProtKB KW
ATP-dependent RNA helicase activitydefinition[GO:0004004]  
2
  • UniProtKB
  • HGNC
Chromatin bindingdefinition[GO:0003682]  
1
  • HGNC
DNA bindingdefinition[GO:0003677] silver  
1
  • InterPro 2 GO
Helicase activitydefinition[GO:0004386]  
1
  • UniProtKB
Poly(A) RNA bindingdefinition[GO:0044822]  
2
  • UniProtKB
Protein bindingdefinition[GO:0005515]  
26
  • IntAct
  • UniProtKB
  • HGNC
RNA bindingdefinition[GO:0003723]  
1
  • UniProtKB
Zinc ion bindingdefinition[GO:0008270] silver  
1
  • InterPro 2 GO
GO biological process 
DNA repairdefinition[GO:0006281]  
1
  • HGNC
DNA replicationdefinition[GO:0006260]  
1
  • HGNC
Dosage compensation by inactivation of X chromosomedefinition[GO:0009048] silver  
1
  • Ortholog Compara
Histone mRNA catabolic processdefinition[GO:0071044]  
1
  • UniProtKB
mRNA export from nucleusdefinition[GO:0006406]  
1
  • HGNC
Nuclear-transcribed mRNA catabolic processdefinition[GO:0000956]  
1
  • UniProtKB
Nuclear-transcribed mRNA catabolic process, nonsense-mediated decaydefinition[GO:0000184]  
4
  • UniProtKB
Regulation of translational terminationdefinition[GO:0006449]  
2
  • UniProtKB
Pathways 
According to KEGG, this protein belongs to the following pathways:
mRNA surveillance pathway  hsa03015+5976  
RNA transport  hsa03013+5976  
According to Reactome, this protein belongs to the following pathways:
Nonsense Mediated Decay (NMD) enhanced by the Exon Junction Complex (EJC)  REACT_75822  
Nonsense Mediated Decay (NMD) independent of the Exon Junction Complex (EJC)  REACT_75768  
 

Keywords

Biological process 
Nonsense-mediated mRNA decay  definition   [KW-0866]
Molecular function 
Helicase  definition   [KW-0347]
Hydrolase  definition   [KW-0378]
Technical term 
Reference proteome  definition   [KW-1185]
 

Further external links

GeneWiki: UPF1
GenomeRNAi: 5976
PRO: PR:Q92900