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Eukaryotic translation initiation factor 1
Protein EIF1 PDB 2if1.png
PDB rendering based on 2if1.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols EIF1 ; A121; EIF-1; EIF1A; ISO1; SUI1
External IDs MGI3643981 HomoloGene130538 GeneCards: EIF1 Gene
Species Human Mouse
Entrez 10209 432950
Ensembl ENSG00000173812 ENSMUSG00000035530
UniProt P41567 P48024
RefSeq (mRNA) NM_005801 n/a
RefSeq (protein) NP_005792 n/a
Location (UCSC) Chr 17:
39.85 – 39.85 Mb
Chr 11:
100.32 – 100.32 Mb
PubMed search [1] [2]

Eukaryotic translation initiation factor 1 is a protein that in humans is encoded by the EIF1 gene.[1][2][3]

Mammalian 17-kDa eukaryotic initiation factor, eIF1A (formerly designated eIF-4C), is essential for transfer of the initiator Met-tRNAf (as Met-tRNAf·eIF2·GTP ternary complex) to 40 S ribosomal subunits in the absence of mRNA to form the 40 S preinitiation complex (40 S·Met-tRNAf·eIF2·GTP). Furthermore, eIF1A acts catalytically in this reaction to mediate highly efficient transfer of the Met-tRNAf·eIF2·GTP ternary complex to 40 S ribosomal subunits. The 40 S complex formed is free of eIF1A which indicates that its role in 40 S preinitiation complex formation is not to stabilize the binding of Met-tRNAf to 40 S ribosomes. Additionally, the eIF1A-mediated 40 S initiation complex formed in the presence of AUG codon efficiently joins 60 S ribosomal subunits in an eIF5-dependent reaction to form a functional 80 S initiation complex. Though found in some reports, eIF1A probably plays no role either in the subunit joining reaction or in the generation of ribosomal subunits from 80 S ribosomes. The major function of eIF1A is to mediate the transfer of Met-tRNAf to 40 S ribosomal subunits to form the 40 S preinitiation complex.[4]


  1. ^ Fields C, Adams MD (Feb 1994). "Expressed sequence tags identify a human isolog of the suil translation initiation factor". Biochem Biophys Res Commun 198 (1): 288–91. doi:10.1006/bbrc.1994.1040. PMID 7904817. 
  2. ^ Sheikh MS, Fernandez-Salas E, Yu M, Hussain A, Dinman JD, Peltz SW, Huang Y, Fornace AJ Jr (Jul 1999). "Cloning and characterization of a human genotoxic and endoplasmic reticulum stress-inducible cDNA that encodes translation initiation factor 1(eIF1(A121/SUI1))". J Biol Chem 274 (23): 16487–93. doi:10.1074/jbc.274.23.16487. PMID 10347211. 
  3. ^ "Entrez Gene: EIF1 eukaryotic translation initiation factor 1". 
  4. ^ Umadas Maitra, Jayanta Chaudhuri; Jayanta Chaudhuri; Kausik Si (21 March 1997). "Function of Eukaryotic Translation Initiation Factor 1A (eIF1A) (Formerly Called eIF-4C) in Initiation of Protein Synthesis" (PDF). The Journal of BIological Chemistry 272 (12): 7883–7891. doi:10.1074/jbc.272.12.7883. Retrieved 19 February 2012. 

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