Cargando…

eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control

In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of tr...

Descripción completa

Detalles Bibliográficos
Autores principales: Jennings, Martin D., Kershaw, Christopher J., White, Christopher, Hoyle, Danielle, Richardson, Jonathan P., Costello, Joseph L., Donaldson, Ian J., Zhou, Yu, Pavitt, Graham D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5175340/
https://www.ncbi.nlm.nih.gov/pubmed/27458202
http://dx.doi.org/10.1093/nar/gkw657
_version_ 1782484643725967360
author Jennings, Martin D.
Kershaw, Christopher J.
White, Christopher
Hoyle, Danielle
Richardson, Jonathan P.
Costello, Joseph L.
Donaldson, Ian J.
Zhou, Yu
Pavitt, Graham D.
author_facet Jennings, Martin D.
Kershaw, Christopher J.
White, Christopher
Hoyle, Danielle
Richardson, Jonathan P.
Costello, Joseph L.
Donaldson, Ian J.
Zhou, Yu
Pavitt, Graham D.
author_sort Jennings, Martin D.
collection PubMed
description In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of translational control. Here we characterize a growth suppressor mutation in eIF2β that prevents eIF5 GDI and alters cellular responses to reduced eIF2B activity, including control of GCN4 translation. By monitoring the binding of fluorescent nucleotides and initiator tRNA to purified eIF2 we show that the eIF2β mutation does not affect intrinsic eIF2 affinities for these ligands, neither does it interfere with eIF2 binding to 43S pre-initiation complex components. Instead we show that the eIF2β mutation prevents eIF5 GDI stabilizing nucleotide binding to eIF2, thereby altering the off-rate of GDP from eIF2•GDP/eIF5 complexes. This enables cells to grow with reduced eIF2B GEF activity but impairs activation of GCN4 targets in response to amino acid starvation. These findings provide support for the importance of eIF5 GDI activity in vivo and demonstrate that eIF2β acts in concert with eIF5 to prevent premature release of GDP from eIF2γ and thereby ensure tight control of protein synthesis initiation.
format Online
Article
Text
id pubmed-5175340
institution National Center for Biotechnology Information
language English
publishDate 2016
publisher Oxford University Press
record_format MEDLINE/PubMed
spelling pubmed-51753402016-12-27 eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control Jennings, Martin D. Kershaw, Christopher J. White, Christopher Hoyle, Danielle Richardson, Jonathan P. Costello, Joseph L. Donaldson, Ian J. Zhou, Yu Pavitt, Graham D. Nucleic Acids Res Gene regulation, Chromatin and Epigenetics In protein synthesis translation factor eIF2 binds initiator tRNA to ribosomes and facilitates start codon selection. eIF2 GDP/GTP status is regulated by eIF5 (GAP and GDI functions) and eIF2B (GEF and GDF activities), while eIF2α phosphorylation in response to diverse signals is a major point of translational control. Here we characterize a growth suppressor mutation in eIF2β that prevents eIF5 GDI and alters cellular responses to reduced eIF2B activity, including control of GCN4 translation. By monitoring the binding of fluorescent nucleotides and initiator tRNA to purified eIF2 we show that the eIF2β mutation does not affect intrinsic eIF2 affinities for these ligands, neither does it interfere with eIF2 binding to 43S pre-initiation complex components. Instead we show that the eIF2β mutation prevents eIF5 GDI stabilizing nucleotide binding to eIF2, thereby altering the off-rate of GDP from eIF2•GDP/eIF5 complexes. This enables cells to grow with reduced eIF2B GEF activity but impairs activation of GCN4 targets in response to amino acid starvation. These findings provide support for the importance of eIF5 GDI activity in vivo and demonstrate that eIF2β acts in concert with eIF5 to prevent premature release of GDP from eIF2γ and thereby ensure tight control of protein synthesis initiation. Oxford University Press 2016-11-16 2016-07-25 /pmc/articles/PMC5175340/ /pubmed/27458202 http://dx.doi.org/10.1093/nar/gkw657 Text en © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Gene regulation, Chromatin and Epigenetics
Jennings, Martin D.
Kershaw, Christopher J.
White, Christopher
Hoyle, Danielle
Richardson, Jonathan P.
Costello, Joseph L.
Donaldson, Ian J.
Zhou, Yu
Pavitt, Graham D.
eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control
title eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control
title_full eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control
title_fullStr eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control
title_full_unstemmed eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control
title_short eIF2β is critical for eIF5-mediated GDP-dissociation inhibitor activity and translational control
title_sort eif2β is critical for eif5-mediated gdp-dissociation inhibitor activity and translational control
topic Gene regulation, Chromatin and Epigenetics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5175340/
https://www.ncbi.nlm.nih.gov/pubmed/27458202
http://dx.doi.org/10.1093/nar/gkw657
work_keys_str_mv AT jenningsmartind eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT kershawchristopherj eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT whitechristopher eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT hoyledanielle eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT richardsonjonathanp eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT costellojosephl eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT donaldsonianj eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT zhouyu eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol
AT pavittgrahamd eif2biscriticalforeif5mediatedgdpdissociationinhibitoractivityandtranslationalcontrol