Reference: Dev K, et al. (2010) The beta/Gcd7 subunit of eukaryotic translation initiation factor 2B (eIF2B), a guanine nucleotide exchange factor, is crucial for binding eIF2 in vivo. Mol Cell Biol 30(21):5218-33

Reference Help

Abstract


Eukaryotic translation initiation factor 2B (eIF2B) is the guanine nucleotide exchange factor (GEF) for eukaryotic translation initiation factor 2, which stimulates formation of the eIF2-GTP-Met-tRNA(i)(Met) ternary complex (TC) in a manner inhibited by phosphorylated eIF2 [eIF2(αP)]. While eIF2B contains five subunits, the ε/Gcd6 subunit is sufficient for GEF activity in vitro. The δ/Gcd2 and β/Gcd7 subunits function with α/Gcn3 in the eIF2B regulatory subcomplex that mediates tight, inhibitory binding of eIF2(αP)-GDP, but the essential functions of δ/Gcd2 and β/Gcd7 are not well understood. We show that the depletion of wild-type β/Gcd7, three lethal β/Gcd7 amino acid substitutions, and a synthetically lethal combination of substitutions in β/Gcd7 and eIF2α all impair eIF2 binding to eIF2B without reducing ε/Gcd6 abundance in the native eIF2B-eIF2 holocomplex. Additionally, β/Gcd7 mutations that impair eIF2B function display extensive allele-specific interactions with mutations in the S1 domain of eIF2α (harboring the phosphorylation site), which binds to eIF2B directly. Consistent with this, β/Gcd7 can overcome the toxicity of eIF2(αP) and rescue native eIF2B function when overexpressed with δ/Gcd2 or γ/Gcd1. In aggregate, these findings provide compelling evidence that β/Gcd7 is crucial for binding of substrate by eIF2B in vivo, beyond its dispensable regulatory role in the inhibition of eIF2B by eIF (αP).

Reference Type
Journal Article | Research Support, N.I.H., Intramural
Authors
Dev K, Qiu H, Dong J, Zhang F, Barthlme D, Hinnebusch AG
Primary Lit For
GCD2 | GCD7 | Eukaryotic translation initiation factor 2B complex
Additional Lit For
IMT4 | IMT3 | SUI2 | GCN3 | IMT2 | GCD1 | IMT1 | gcd2-td | gcd7-td | gcd6-td | gcd7-358-360 | ... Show all

Interaction Annotations


Genetic Interactions

Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Allele Assay Annotation Action Phenotype SGA score P-value Source Reference

Physical Interactions 28 entries for 8 genes

Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

InteractorInteractorAssayAnnotationActionModification
GCD1SUI3Affinity Capture-Westernmanually curatedHit-BaitNo Modification
GCD11GCD2Affinity Capture-Westernmanually curatedHit-BaitNo Modification
GCD11GCD6Affinity Capture-Westernmanually curatedHit-BaitNo Modification
GCD11SUI3Affinity Capture-Westernmanually curatedHit-BaitNo Modification
GCD11GCD7Affinity Capture-Westernmanually curatedHit-BaitNo Modification
GCD2GCD7Affinity Capture-Westernmanually curatedBait-HitNo Modification
GCD2GCD1Affinity Capture-Westernmanually curatedBait-HitNo Modification
GCD2SUI2Affinity Capture-Westernmanually curatedBait-HitNo Modification
GCD2SUI3Affinity Capture-Westernmanually curatedBait-HitNo Modification
GCD2SUI3Affinity Capture-Westernmanually curatedHit-BaitNo Modification
Showing 1 to 10 of 28 entries