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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2006-5-1
pubmed:abstractText
The GTP-binding eukaryotic translation initiation factor eIF2 delivers initiator methionyl-tRNA to the 40 S ribosomal subunit. The factor eIF5 stimulates hydrolysis of GTP by eIF2 upon AUG codon recognition, whereas the factor eIF2B promotes guanine nucleotide exchange on eIF2 to recycle the factor for additional rounds of translation initiation. The GTP-binding (G) domain resides in the gamma subunit of the heterotrimeric eIF2; however, only eIF2beta, and not eIF2gamma, has been reported to directly bind to eIF5 or eIF2B. Using proteins expressed in yeast or recombinant systems we show that full-length yeast eIF2gamma, as well as its isolated G domain, binds directly to eIF5 and the epsilon subunit of eIF2B, and we map the interaction sites to the catalytically important regions of these factors. Consistently, an internal deletion of residues 50-100 of yeast eIF5 impairs the interaction with recombinant eIF2gamma-G domain and abolishes the ability of eIF5 to stimulate eIF2 GTPase activity in translation initiation complexes in vitro. Thus, rather than allosterically regulating eIF2gamma-G domain function via eIF2beta, our data support a model in which the GTPase-activating factor eIF5 and the guanine-nucleotide exchange factor eIF2B modulate eIF2 function through direct interactions with the eIF2gamma-G domain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
281
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12636-44
pubmed:dateRevised
2009-7-24
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Direct binding of translation initiation factor eIF2gamma-G domain to its GTPase-activating and GDP-GTP exchange factors eIF5 and eIF2B epsilon.
pubmed:affiliation
Laboratory of Gene Regulation and Development, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Intramural