Archaeal aIF2B interacts with eukaryotic translation initiation factors eIF2alpha and eIF2Balpha: Implications for aIF2B function and eIF2B regulation.

ABSTRACT: Translation initiation is down-regulated in eukaryotes by phosphorylation of the alpha-subunit of eIF2 (eukaryotic initiation factor 2), which inhibits its guanine nucleotide exchange factor, eIF2B. The N-terminal S1 domain of phosphorylated eIF2alpha interacts with a subcomplex of eIF2B formed by the three regulatory subunits alpha/GCN3, beta/GCD7, and delta/GCD2, blocking the GDP-GTP exchange activity of the catalytic epsilon-subunit of eIF2B. These regulatory subunits have related sequences and have sequences in common with many archaeal proteins, some of which are involved in methionine salvage and CO(2) fixation. Our sequence analyses however predicted that members of one phylogenetically distinct and coherent group of these archaeal proteins [designated aIF2Bs (archaeal initiation fa

SUBMITTER: Dev K 

PROVIDER: S-EPMC2937263 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature