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PMID: 11333223 Published · ppublish English Journal Article Research Support, Non-U.S. Gov't

Minimum requirements for the function of eukaryotic translation initiation factor 2.

Genetics ·Vol. 158 ·No. 1 ·2001-05-00 ·Pages 123-32

Erickson FL, Nika J, Rippel S, Hannig EM

Abstract

Eukaryotic translation initiation factor 2 (eIF2) is a G protein heterotrimer required for GTP-dependent delivery of initiator tRNA to the ribosome. eIF2B, the nucleotide exchange factor for eIF2, is a heteropentamer that, in yeast, is encoded by four essential genes and one nonessential gene. We found that increased levels of wild-type eIF2, in the presence of sufficient levels of initiator tRNA, overcome the requirement for eIF2B in vivo. Consistent with bypassing eIF2B, these conditions also suppress the lethal effect of overexpressing the mammalian tumor suppressor PKR, an eIF2alpha kinase. The effects described are further enhanced in the presence of a mutation in the G protein (gamma) subunit of eIF2, gcd11-K250R, which mimics the function of eIF2B in vitro. Interestingly, the same conditions that bypass eIF2B also overcome the requirement for the normally essential eIF2alpha structural gene (SUI2). Our results suggest that the eIF2betagamma complex is capable of carrying out the essential function(s) of eIF2 in the absence of eIF2alpha and eIF2B and are consistent with the idea that the latter function primarily to regulate the level of eIF2.GTP.Met-tRNA(i)(Met) ternary complexes in vivo.

MeSH Terms
Cell Division Eukaryotic Initiation Factor-2/genetics,physiology Gene Dosage Genes, Fungal Homeostasis eIF-2 Kinase/metabolism
Chemicals
Eukaryotic Initiation Factor-2 eIF-2 Kinase
Authors & Affiliations
4 authors, click to expand affiliations / ORCID
Erickson F L
Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, TX 75083-0688, USA.
Nika J
Rippel S
Hannig E M
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Article Info
Journal
Genetics
Abbr.
Genetics
ISSN
0016-6731
DOI
10.1093/genetics/158.1.123
Published
2001-05-00
Pages
123-32
Language
English
Region
United States
NLM ID
0374636
PMCID
PMC1461651
Subset
IM
External Links
PubMed source DOI: 10.1093/genetics/158.1.123 PMC Full Text View journal details
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