EIF1
Protein-coding gene in the species Homo sapiens
From Wikipedia, the free encyclopedia
Eukaryotic translation initiation factor 1 (eIF1) is a protein that in humans is encoded by the EIF1 gene. It is related to yeast SUI1.[5][6][7]
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| Aliases | EIF1, A121, EIF-1, ISO1, SUI1, eukaryotic translation initiation factor 1, Eukaryotic initiation factor 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||
| External IDs | MGI: 105125; HomoloGene: 130538; GeneCards: EIF1; OMA:EIF1 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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eIF1 interacts with the eukaryotic small (40S) ribosomal subunit and eIF3, and is a component of the 43S preinitiation complex (PIC).[8] eIF1 and eIF1A bind cooperatively to the 40S to stabilize an "open" conformation of the preinitiation complex (PIC) during eukaryotic translation initiation.[8] eIF1 binds to a region near the ribosomal P-site in the 40S subunit and functions in a manner similar to the structurally related bacterial counterpart IF3.[9]
Structure
eIF1's structure was first determined in 1999 by solution-state NMR spectroscopy, which revealed that it consists of a five-stranded beta-sheet which is sided by two alpha-helices.[10] Crystallographic experiments showed that eIF1 is located at the P-site of the small ribosomal subunit, binding to the 18S rRNA with a basic surface.[11] To date, a number of cryo-EM structures have been solved that include eIF1 in the context of various translation initiation complexes.[12][13][14]
Function
In eukaryotic cells, translation initiation on an mRNA involves scanning of the mRNA by the 43S pre-initiation complex in search of the translation initiation start codon.[15] Accurate identification of the start codon is very important, as other translation start sites may lead to the production of defect proteins. A codon is detected as a start codon by interaction with the tRNA's anticodon that is positioned in the P-site of the small ribosomal subunit, which leads to closing of the pre-initiation complex.[16] eIF1 is positioned on the small ribosomal subunit such that it blocks the closure of the pre-initiation complex. It thereby aids in selecting the correct start codon, since only the correct codon-anticodon interaction provides enough energy to displace eIF1 and thus close the pre-initiation complex.[17]