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P83268 (IF2A_RABIT) Reviewed, UniProtKB/Swiss-Prot

Last modified April 16, 2014. Version 68. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
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Names and origin

Protein namesRecommended name:
Eukaryotic translation initiation factor 2 subunit 1
Alternative name(s):
Eukaryotic translation initiation factor 2 subunit alpha
Short name=eIF-2-alpha
Short name=eIF-2A
Short name=eIF-2alpha
Gene names
OrganismOryctolagus cuniculus (Rabbit) [Reference proteome]
Taxonomic identifier9986 [NCBI]
Taxonomic lineageEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresLagomorphaLeporidaeOryctolagus

Protein attributes

Sequence length52 AA.
Sequence statusFragment.
Protein existenceEvidence at protein level

General annotation (Comments)


Functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA. This complex binds to a 40S ribosomal subunit, followed by mRNA binding to form a 43S preinitiation complex. Junction of the 60S ribosomal subunit to form the 80S initiation complex is preceded by hydrolysis of the GTP bound to eIF-2 and release of an eIF-2-GDP binary complex. In order for eIF-2 to recycle and catalyze another round of initiation, the GDP bound to eIF-2 must exchange with GTP by way of a reaction catalyzed by eIF-2B.

Subunit structure

Heterotrimer composed of an alpha, a beta and a gamma chain. Component of an EIF2 complex at least composed of CELF1/CUGBP1, CALR, CALR3, EIF2S1, EIF2S2, HSP90B1 and HSPA5. Interacts with ABCF1. Associates with ribosomes. Interaction with METAP2 protects EIF2S1 from inhibitory phosphorylation By similarity.

Subcellular location

Cytoplasmic granule By similarity. Note: The cytoplasmic granules are stress granules which are a dense aggregation in the cytosol composed of proteins and RNAs that appear when the cell is under stress. Colocalizes with NANOS3 in the stress granules By similarity.

Post-translational modification

Substrate for at least 4 kinases: EIF2AK3/PERK, GCN2, HRI and PKR. Phosphorylation stabilizes the eIF-2/GDP/eIF-2B complex and prevents GDP/GTP exchange reaction, thus impairing the recycling of eIF-2 between successive rounds of initiation and leading to global inhibition of translation By similarity.

Sequence similarities

Belongs to the eIF-2-alpha family.

Contains 1 S1 motif domain.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – ›52›52Eukaryotic translation initiation factor 2 subunit 1


Domain16 – ›52›37S1 motif

Amino acid modifications

Modified residue481Phosphoserine; by HRI Ref.1
Modified residue511Phosphoserine; by EIF2AK3, GCN2, HRI and PKR By similarity

Experimental info

Sequence uncertainty101
Sequence uncertainty441
Sequence uncertainty521
Sequence conflict101H → R AA sequence Ref.2
Sequence conflict161E → Q AA sequence Ref.1
Non-terminal residue521


Sequence LengthMass (Da)Tools
P83268 [UniParc].

Last modified March 1, 2002. Version 1.
Checksum: 52E63D8DCEA6B804

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[1]"The NH2-terminal sequence of the alpha and gamma subunits of eukaryotic initiation factor 2 and the phosphorylation site for the heme-regulated eIF-2 alpha kinase."
Wettenhall R.E.H., Kudlicki W., Kramer G., Hardesty B.
J. Biol. Chem. 261:12444-12447(1986) [PubMed] [Europe PMC] [Abstract]
Tissue: Reticulocyte.
[2]"The purification and characterization of subunits alpha, beta, and gamma from the rabbit reticulocyte eukaryotic initiation factor 2."
Schafer M.P., Fairwell T., Parker D.S., Knight M., Anderson W.F., Safer B.
Arch. Biochem. Biophys. 255:337-346(1987) [PubMed] [Europe PMC] [Abstract]
Cited for: PROTEIN SEQUENCE OF 1-23.
Tissue: Reticulocyte.


3D structure databases

SMRP83268. Positions 3-50.

Protein-protein interaction databases

IntActP83268. 1 interaction.

Protocols and materials databases


Phylogenomic databases


Family and domain databases

Gene3D2.40.50.140. 1 hit.
InterProIPR012340. NA-bd_OB-fold.
IPR003029. Rbsml_prot_S1_RNA-bd_dom.
[Graphical view]
PfamPF00575. S1. 1 hit.
[Graphical view]
SUPFAMSSF50249. SSF50249. 1 hit.
PROSITEPS50126. S1. 1 hit.
[Graphical view]

Entry information

Entry nameIF2A_RABIT
AccessionPrimary (citable) accession number: P83268
Entry history
Integrated into UniProtKB/Swiss-Prot: May 27, 2002
Last sequence update: March 1, 2002
Last modified: April 16, 2014
This is version 68 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Relevant documents


Index of protein domains and families

Translation initiation factors

List of translation initiation factor entries