EIF5B

Eukaryotic translation initiation factor 5B is a protein that in humans is encoded by the EIF5B gene.^[5][6][7] eIF5B is homologous to the bacterial initiation factor 2, sharing a core structure while their involvement in translation initiation differs.^[8]

EIF5B
Identifiers
Aliases	EIF5B, IF2, eukaryotic translation initiation factor 5B
External IDs	OMIM: 606086; MGI: 2441772; HomoloGene: 134613; GeneCards: EIF5B; OMA:EIF5B - orthologs
Gene location (Human) Chr. Chromosome 2 (human)[1] Band 2q11.2 Start 99,337,371 bp[1] End 99,401,326 bp[1]
Gene location (Mouse) Chr. Chromosome 1 (mouse)[2] Band 1|1 B Start 38,037,091 bp[2] End 38,094,660 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in tendon of biceps brachii oocyte secondary oocyte internal globus pallidus myocardium of left ventricle gingival epithelium pericardium pars reticulata cardia external globus pallidus Top expressed in tail of embryo lens genital tubercle zygote epithelium of lens secondary oocyte parotid gland lacrimal gland primary oocyte epiblast More reference expression data BioGPS More reference expression data
Gene ontology Molecular function nucleotide binding protein binding metal ion binding GTP binding hydrolase activity translation initiation factor activity RNA binding GTPase activity Cellular component cytosol nucleus cytoplasm Biological process regulation of translational initiation translational initiation protein biosynthesis Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 9669 226982 Ensembl ENSG00000158417 ENSMUSG00000026083 UniProt O60841 Q05D44 RefSeq (mRNA) NM_015904 NM_198303 RefSeq (protein) NP_056988 NP_938045 Location (UCSC) Chr 2: 99.34 – 99.4 Mb Chr 1: 38.04 – 38.09 Mb PubMed search [3] [4]
Wikidata
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Function

See also: Eukaryotic translation § Cap-dependent initiation

eIF5B plays an important role in later stages of the translation initiation mechanism. After the start codon has been engaged by the scanning initiation complex, eukaryotic initiation factors eIF1, eIF2, and eIF5 leave the ribosome. Subsequently, eIF5B-GTP is recruited to the ribosome. eIF1A induces rotation of a domain of eIF5B-GTP, which in turn positions the initiator tRNA such that joining of the large ribosomal subunit is possible.^[9] Joining of the large subunit causes hydrolysis of the eIF5B-bound GTP, which accelerates the release of eIF1A from the ribosome.^[10] Dissociation of eIF1A leads to another rearrangement of eIF5B, placing the initiator tRNA in its final position.^[11] The hydrolysis of eIF5B's GTP reduces its affinity to the ribosome, ultimately leading to its dissociation. This concludes the initiation of translation.