Eukaryotic translation initiation factor 3 subunit I (EIF3I)
The protein contains 325 amino acids for an estimated molecular weight of 36502 Da.
Component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is required for several steps in the initiation of protein synthesis (PubMed:17581632, PubMed:25849773, PubMed:27462815). The eIF-3 complex associates with the 40S ribosome and facilitates the recruitment of eIF-1, eIF-1A, eIF-2:GTP:methionyl-tRNAi and eIF-5 to form the 43S pre-initiation complex (43S PIC). The eIF-3 complex stimulates mRNA recruitment to the 43S PIC and scanning of the mRNA for AUG recognition. The eIF-3 complex is also required for disassembly and recycling of post-termination ribosomal complexes and subsequently prevents premature joining of the 40S and 60S ribosomal subunits prior to initiation (PubMed:17581632). The eIF-3 complex specifically targets and initiates translation of a subset of mRNAs involved in cell proliferation, including cell cycling, differentiation and apoptosis, and uses different modes of RNA stem-loop binding to exert either translational activation or repression (PubMed:25849773). (updated: Nov. 22, 2017)
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.
- 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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Biological Process
Cellular protein metabolic process
Cytoplasmic translational initiation
Formation of cytoplasmic translation initiation complex
Formation of translation preinitiation complex
Gene expression
Regulation of translational initiation
Translation
Translational initiation
The reference OMIM entry for this protein is 603911
Eukaryotic translation initiation factor 3, subunit i; eif3i
Tgf-beta receptor-interacting protein 1; trip1
Eif3-p36
Eif3-beta
Eukaryotic translation initiation factor 3, subunit 2, formerly; eif3s2, formerly
CLONING
Eukaryotic initiation factor-3 (eIF3) is the largest of the eIFs and consists of at least 10 nonidentical subunits in mammals. See p66 (EIF3S7; 603915). In S. cerevisiae, the p39 subunit of eIF3 contains WD repeats, which are thought to mediate protein-protein interactions. The p39 protein appears to be essential for maintaining the integrity of the yeast eIF3 complex. The mammalian eIF3-p36 subunit is homologous to yeast p39. By searching an EST database for sequences corresponding to the partial protein sequence of rabbit p36, Asano et al. (1997) identified a cDNA encoding human p36. The predicted 325-amino acid human protein shares 46% identity with yeast p39. Like p39, p36 contains 5 WD repeats and 2 less conserved WD repeat elements. The authors found that the p116 (603917), p110 (603916), and p36 subunits localize on 40S ribosomes in cells active in translation and coimmunoprecipitate with p170 (602039), indicating that these proteins are integral components of eIF3. Northern blot analysis revealed that p36 is expressed as a 1.6-kb mRNA in HeLa cells. Transforming growth factor-beta (TGF-beta; see 190180) signaling is mediated by the type I (RI; 190181) and type II (RII; 190182) TGF-beta serine/threonine kinase receptors, which are able to form a heteromeric complex. Chen et al. (1995) identified eIF3-p36 as TRIP1 (TGF-beta receptor-interacting protein-1), a protein that specifically associates with RII. The association with RII requires RII's kinase activity, suggesting that receptor autophosphorylation creates a binding site for TRIP1. Since TRIP1 is phosphorylated on serine and threonine by the receptor kinase, the authors proposed that TRIP1 plays a role in TGF-beta signaling. Northern blot analysis indicated that TRIP1 was expressed as a 1.6-kb mRNA in all human fetal tissues tested. In mouse embryos, the immunolocalization patterns of TRIP1 and RII were well correlated, further supporting a functional correlation between both proteins.GENE STRUCTURE
Galli-Stauber et al. (1998) reported that the p36 gene contains 11 exons and spans 9 kb.MAPPING
By fluorescence in situ hybridization, Galli-Stauber et al. (1998) mapped the TRIP1 gene to 1p34.1 and a TRIP1 pseudogene to 7q32. ... More on the omim web site
Feb. 10, 2018: Protein entry updated
Automatic update: Entry updated from uniprot information.
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
June 20, 2017: Protein entry updated
Automatic update: comparative model was added.
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 603911 was added.