Published 12 September 2005. doi:10.1083/jcb.200503162
The Rockefeller University Press, 0021-9525 $8.00
JCB, Volume 170, Number 6, 925-934
Dynamic cycling of eIF2 through a large eIF2B-containing cytoplasmic body
:
implications for translation control
Susan G. Campbell,
Nathaniel P. Hoyle, and
Mark P. Ashe
Faculty of Life Science, The University of Manchester, Manchester, M13 9PT, England, UK
Correspondence to Mark Ashe: mark.p.ashe{at}manchester.ac.uk
The eukaryotic translation initiation factor 2B (eIF2B) provides a fundamental controlled point in the pathway of protein synthesis. eIF2B is the heteropentameric guanine nucleotide exchange factor that converts eIF2, from an inactive guanosine diphosphatebound complex to eIF2-guanosine triphosphate. This reaction is controlled in response to a variety of cellular stresses to allow the rapid reprogramming of cellular gene expression. Here we demonstrate that in contrast to other translation initiation factors, eIF2B and eIF2 colocalize to a specific cytoplasmic locus. The dynamic nature of this locus is revealed through fluorescence recovery after photobleaching analysis. Indeed eIF2 shuttles into these foci whereas eIF2B remains largely resident. Three different strategies to decrease the guanine nucleotide exchange function of eIF2B all inhibit eIF2 shuttling into the foci. These results implicate a defined cytoplasmic center of eIF2B in the exchange of guanine nucleotides on the eIF2 translation initiation factor. A focused core of eIF2B guanine nucleotide exchange might allow either greater activity or control of this elementary conserved step in the translation pathway.
Abbreviations used in this paper: eIF, eukaryotic initiation factor; Met-tRNAiMet, initiator methionyl tRNA; MFC, multifactor complex; SCD, synthetic complete media; TC, ternary complex.

CiteULike
Complore
Connotea
Del.icio.us
Digg
Facebook
Reddit
Technorati
Twitter What's this?
Related Article
-
eIF2 activated in spots
- Nicole LeBrasseur
J. Cell Biol. 2005 170: 861.
[Full Text]
[PDF]
This article has been cited by other articles:
-
Grousl, T., Ivanov, P., Frydlova, I., Vasicova, P., Janda, F., Vojtova, J., Malinska, K., Malcova, I., Novakova, L., Janoskova, D., Valasek, L., Hasek, J.
(2009). Robust heat shock induces eIF2{alpha}-phosphorylation-independent assembly of stress granules containing eIF3 and 40S ribosomal subunits in budding yeast, Saccharomyces cerevisiae. J. Cell Sci.
122: 2078-2088
[Abstract]
[Full Text]
-
Dimelow, R. J, Wilkinson, S. J
(2009). Control of translation initiation: a model-based analysis from limited experimental data. J R Soc Interface
6: 51-61
[Abstract]
[Full Text]
-
Buchan, J. R., Muhlrad, D., Parker, R.
(2008). P bodies promote stress granule assembly in Saccharomyces cerevisiae. JCB
183: 441-455
[Abstract]
[Full Text]
-
Hoyle, N. P., Castelli, L. M., Campbell, S. G., Holmes, L. E.A., Ashe, M. P.
(2007). Stress-dependent relocalization of translationally primed mRNPs to cytoplasmic granules that are kinetically and spatially distinct from P-bodies. JCB
179: 65-74
[Abstract]
[Full Text]
-
Marciniak, S. J., Garcia-Bonilla, L., Hu, J., Harding, H. P., Ron, D.
(2006). Activation-dependent substrate recruitment by the eukaryotic translation initiation factor 2 kinase PERK. JCB
172: 201-209
[Abstract]
[Full Text]