The translation factor eIF5 is an important partner of eIF2, directly modulating its function in several critical steps. First, eIF5 binds eIF2/GTP/Met-tRNA(i)(Met) ternary complex (TC), promoting its recruitment to 40S ribosomal subunits. Secondly, its GTPase activating function promotes eIF2 dissociation for ribosomal subunit joining. Finally, eIF5 GDP dissociation inhibition (GDI) activity can antagonize eIF2 reactivation by competing with the eIF2 guanine exchange factor (GEF), eIF2B. The C-terminal domain (CTD) of eIF5, a W2-type HEAT domain, mediates its interaction with eIF2. Here, we characterize a related human protein containing MA3- and W2-type HEAT domains, previously termed BZW2 and renamed here as eIF5-mimic protein 1 (5MP1). Human 5MP1 interacts with eIF2 and eIF3 and inhibits general and gene-specific translation in mammalian systems. We further test whether 5MP1 is a mimic or competitor of the GEF catalytic subunit eIF2Bε or eIF5, using yeast as a model. Our results suggest that 5MP1 interacts with yeast eIF2 and promotes TC formation, but inhibits TC binding to the ribosome. Moreover, 5MP1 is not a GEF but a weak GDI for yeast eIF2. We propose that 5MP1 is a partial mimic and competitor of eIF5, interfering with the key steps by which eIF5 regulates eIF2 function.
Pubmed ID: 21745818 RIS Download
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An extensible and customizable gene annotation portal that emphasizes community extensibility and user customizability. It is a complete resource for learning about gene and protein function. Community extensibility reflects a belief that any BioGPS user should be able to add new content to BioGPS using the simple plugin interface, completely independently of the core developer team. User customizability recognizes that not all users are interested in the same set of gene annotation data, so the gene report layouts enable each user to define the information that is most relevant to them. Currently, BioGPS supports eight species: Human (Homo sapiens), Mouse (Mus musculus), Rat (Rattus norvegicus), Fruitfly (Drosophila melanogaster), Nematode (Caenorhabditis elegans), Zebrafish (Danio rerio), Thale-cress (Arabidopsis thaliana), Frog (Xenopus tropicalis), and Pig (Sus scrofa). BioGPS presents data in an ortholog-centric format, which allows users to display mouse plugins next to human ones. Our data for defining orthologs comes from NCBI's HomoloGene database.
View all literature mentionsCell line HeLa is a Cancer cell line with a species of origin Homo sapiens
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