ID:EIF3B_HUMAN DESCRIPTION: RecName: Full=Eukaryotic translation initiation factor 3 subunit B; Short=eIF3b; AltName: Full=Eukaryotic translation initiation factor 3 subunit 9; AltName: Full=Prt1 homolog; Short=hPrt1; AltName: Full=eIF-3-eta; AltName: Full=eIF3 p110; AltName: Full=eIF3 p116; FUNCTION: Component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is required for several steps in the initiation of protein synthesis. 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 preinitiation 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. SUBUNIT: Component of the eukaryotic translation initiation factor 3 (eIF-3) complex, which is composed of 13 subunits: EIF3A, EIF3B, EIF3C, EIF3D, EIF3E, EIF3F, EIF3G, EIF3H, EIF3I, EIF3J, EIF3K, EIF3L and EIF3M. The eIF-3 complex appears to include 3 stable modules: module A is composed of EIF3A, EIF3B, EIF3G and EIF3I; module B is composed of EIF3F, EIF3H, and EIF3M; and module C is composed of EIF3C, EIF3D, EIF3E, EIF3K and EIF3L. EIF3C of module C binds EIF3B of module A and EIF3H of module B, thereby linking the three modules. EIF3J is a labile subunit that binds to the eIF-3 complex via EIF3B. The eIF-3 complex interacts with RPS6KB1 under conditions of nutrient depletion. Mitogenic stimulation leads to binding and activation of a complex composed of MTOR and RPTOR, leading to phosphorylation and release of RPS6KB1 and binding of EIF4B to eIF-3. Also interacts with UPF2. INTERACTION: O00571:DDX3X; NbExp=5; IntAct=EBI-366696, EBI-353779; Q14152:EIF3A; NbExp=5; IntAct=EBI-366696, EBI-366617; O75821:EIF3G; NbExp=4; IntAct=EBI-366696, EBI-366632; Q13347:EIF3I; NbExp=4; IntAct=EBI-366696, EBI-354047; O75822:EIF3J; NbExp=5; IntAct=EBI-366696, EBI-366647; SUBCELLULAR LOCATION: Cytoplasm (By similarity). DOMAIN: The RRM domain mediates interaction with EIF3J. PTM: Phosphorylated. Phosphorylation is enhanced upon serum stimulation. MASS SPECTROMETRY: Mass=93093.7; Method=Unknown; Range=1-814; Source=PubMed:17322308; MASS SPECTROMETRY: Mass=92561; Mass_error=43.5; Method=MALDI; Range=1-814; Source=PubMed:18599441; SIMILARITY: Belongs to the eIF-3 subunit B family. SIMILARITY: Contains 1 RRM (RNA recognition motif) domain. SIMILARITY: Contains 5 WD repeats.
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
ModBase Predicted Comparative 3D Structure on P55884
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
AK302058 - Homo sapiens cDNA FLJ53461 complete cds, highly similar to Eukaryotic translation initiation factor 3 subunit 9. BC096753 - Homo sapiens cDNA clone IMAGE:5302741, **** WARNING: chimeric clone ****. U78525 - Homo sapiens eukaryotic translation initiation factor (eIF3) mRNA, complete cds. AK300967 - Homo sapiens cDNA FLJ53410 complete cds, highly similar to Eukaryotic translation initiation factor 3 subunit 9. U62583 - Human Prt1 homolog mRNA, complete cds. BC001173 - Homo sapiens eukaryotic translation initiation factor 3, subunit B, mRNA (cDNA clone MGC:2051 IMAGE:3501759), complete cds. BC110865 - Homo sapiens eukaryotic translation initiation factor 3, subunit B, mRNA (cDNA clone MGC:131875 IMAGE:6175284), complete cds. BC009986 - Homo sapiens eukaryotic translation initiation factor 3, subunit B, mRNA (cDNA clone IMAGE:4124553), partial cds. AB209381 - Homo sapiens mRNA for eukaryotic translation initiation factor 3, subunit 9 eta, 116kDa isoform b variant protein. JD025054 - Sequence 6078 from Patent EP1572962. AK126670 - Homo sapiens cDNA FLJ44714 fis, clone BRACE3020669. JD022875 - Sequence 3899 from Patent EP1572962. JD028460 - Sequence 9484 from Patent EP1572962. AK093807 - Homo sapiens cDNA FLJ36488 fis, clone THYMU2017948. AK127885 - Homo sapiens cDNA FLJ45991 fis, clone RECTM2002632, highly similar to Eukaryotic translation initiation factor 3 subunit 9. JD021921 - Sequence 2945 from Patent EP1572962. JD034600 - Sequence 15624 from Patent EP1572962. JD164686 - Sequence 145710 from Patent EP1572962. JD561606 - Sequence 542630 from Patent EP1572962.
Biochemical and Signaling Pathways
Reactome (by CSHL, EBI, and GO)
Protein P55884 (Reactome details) participates in the following event(s):
R-HSA-72676 eIF3 and eIF1A bind to the 40S subunit R-HSA-72619 eIF2:GTP is hydrolyzed, eIFs are released R-HSA-72691 Formation of the 43S pre-initiation complex R-HSA-156808 Formation of translation initiation complexes yielding circularized Ceruloplasmin mRNA in a 'closed-loop' conformation R-HSA-157849 Formation of translation initiation complexes containing mRNA that does not circularize R-HSA-72621 Ribosomal scanning R-HSA-72697 Start codon recognition R-HSA-156823 Association of phospho-L13a with GAIT element of Ceruloplasmin mRNA R-HSA-72689 Formation of a pool of free 40S subunits R-HSA-72706 GTP hydrolysis and joining of the 60S ribosomal subunit R-HSA-72695 Formation of the ternary complex, and subsequently, the 43S complex R-HSA-72649 Translation initiation complex formation R-HSA-72737 Cap-dependent Translation Initiation R-HSA-72702 Ribosomal scanning and start codon recognition R-HSA-156827 L13a-mediated translation R-HSA-72662 Activation of the mRNA upon binding of the cap-binding complex and eIFs, and subsequent binding to 43S R-HSA-72613 Eukaryotic Translation Initiation R-HSA-72766 Translation R-HSA-392499 Metabolism of proteins
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Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
