Eukaryotic translation initiation factor 2 subunit 2 (EIF2S2)
The protein contains 333 amino acids for an estimated molecular weight of 38388 Da.
eIF-2 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. (updated: March 4, 2015)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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| Variant | Description |
|---|---|
| dbSNP:rs17856024 |
Biological Process
Cellular protein metabolic process
Formation of cytoplasmic translation initiation complex
Formation of translation preinitiation complex
Gene expression
In utero embryonic development
Male germ cell proliferation
Male gonad development
Translation
Translational initiation
Transmembrane transport
The reference OMIM entry for this protein is 603908
Eukaryotic translation initiation factor 2, subunit 2; eif2s2
Eukaryotic translation initiation factor 2-beta
DESCRIPTION
The translation initiation factor eIF2 consists of 3 nonidentical subunits, alpha (EIF2S1; 603907), beta, and gamma (EIF2S3; 300161), all of which are required for the catalytic utilization of eIF2 during protein synthesis initiation.CLONING
By screening a mouse expression library with antibodies against eIF2, Pathak et al. (1988) isolated partial mouse cDNAs encoding eIF2-beta. They then used a mouse cDNA to screen a human liver library and recovered human eIF2-beta cDNAs. The predicted 333-amino acid human protein contains putative GTP-binding sites, a zinc finger motif, and a highly charged N-terminal region composed of 3 basic polylysine blocks separated by acidic domains. Overall, human eIF2-beta shares 42% sequence identity with the yeast Sui3/eIF2-beta protein; the polylysine and zinc finger domains are highly conserved. Pathak et al. (1988) stated that the presence of these domains suggests that eIF2-beta interacts with RNA. Northern blot analysis revealed that eIF2-beta is expressed as a 1.6-kb mRNA in HeLa cells.GENE STRUCTURE
Based on Southern blot analysis, Chiorini et al. (1999) reported that there are 4 copies of the eIF2-beta gene in the human genome, but only 1 contains the entire cDNA sequence and introns. The functional eIF2-beta gene contains 9 exons and spans 28 kb.GENE FUNCTION
Chiorini et al. (1999) demonstrated that, as with eIF2-alpha, eIF2-beta expression is regulated at the transcriptional level by the alpha-Pal (NRF1; 600879) transcription factor. However, while the eIF2-alpha promoter contains 2 alpha-Pal binding sites, the eIF2-beta promoter has only 1. Eukaryotic translation initiation factor-5 (EIF5; 601710) functions in start site selection as a GTPase accelerating protein (GAP) for the EIF2-GTP-tRNAi(Met) ternary complex within the ribosome-bound preinitiation complex (summary by Jennings and Pavitt (2010)). Jennings and Pavitt (2010) defined new regulatory functions of EIF5 in the recycling of EIF2 from its inactive EIF2-GDP state between successive rounds of translation initiation. First, the authors showed that EIF5 stabilizes the binding of GDP to EIF2 and is therefore a bifunctional protein that acts as a GDP dissociation inhibitor (GDI). Jennings and Pavitt (2010) found that this activity is independent of the GAP function and identified conserved residues within EIF5 that are necessary for this role. In addition, Jennings and Pavitt (2010) showed that EIF5 is a critical component of the EIF2(alpha-P) regulatory complex that inhibits the activity of the guanine-nucleotide exchange factor (GEF) EIF2B. Jennings and Pavitt (2010) concluded that their findings defined a new step in the translation initiation pathway, one that is critical for normal translational controls.ANIMAL MODEL
The agouti (ASIP; 600201)-yellow (Ay) deletion is the only genetic modifier known to suppress testicular germ cell tumor (TGCT; 273300) susceptibility in mice or human. The Ay mutation deletes Raly and Eif2s2 and induces the ectopic expression of agouti, all of which are potential TGCT-modifying mutations. Heaney et al. (2009) reported that the reduced TGCT incidence of heterozygous Ay male mice and the recessive embryonic lethality of Ay are caused by the deletion of Eif2s2. The incidence of affected males was reduced 2-fold in mice that were partially deficient for Eif2s2 and that embryonic lethality occurred near the time of implantation in mice that ... More on the omim web site
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 603908 was added.