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Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease
Eukaryotic initiation factor 2B (eIF2B) serves as a vital control point within protein synthesis and regulates translation initiation in response to cellular stress. Mutations within eIF2B result in the fatal disease, leukoencephalopathy with vanishing white matter (VWM). Previous biochemical studie...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7948505/ https://www.ncbi.nlm.nih.gov/pubmed/33334879 http://dx.doi.org/10.1074/jbc.RA120.014956 |
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author | Norris, Karl Hodgson, Rachel E. Dornelles, Tawni Allen, K. Elizabeth Abell, Ben M. Ashe, Mark P. Campbell, Susan G. |
author_facet | Norris, Karl Hodgson, Rachel E. Dornelles, Tawni Allen, K. Elizabeth Abell, Ben M. Ashe, Mark P. Campbell, Susan G. |
author_sort | Norris, Karl |
collection | PubMed |
description | Eukaryotic initiation factor 2B (eIF2B) serves as a vital control point within protein synthesis and regulates translation initiation in response to cellular stress. Mutations within eIF2B result in the fatal disease, leukoencephalopathy with vanishing white matter (VWM). Previous biochemical studies on VWM mutations have illustrated that changes in the activity of eIF2B poorly correlate with disease severity. This suggests that there may be additional characteristics of eIF2B contributing to VWM pathogenesis. Here, we investigated whether the localization of eIF2B to eIF2B bodies was integral for function and whether this localization could provide insight into the pathogenesis of VWM. We demonstrate that the regulatory subunit, eIF2Bα, is required for the assembly of eIF2B bodies in yeast and that loss of eIF2B bodies correlates with an inability of cells to regulate eIF2B activity. Mutational analysis of eIF2Bα showed that missense mutations that disrupt the regulation of eIF2B similarly disrupt the assembly of eIF2B bodies. In contrast, when eIF2Bα mutations that impact the catalytic activity of eIF2B were analyzed, eIF2B bodies were absent and instead eIF2B localized to small foci, termed microfoci. Fluorescence recovery after photobleaching analysis highlighted that within these microfoci, eIF2 shuttles more slowly indicating that formation of eIF2B bodies correlates with full eIF2B activity. When eIF2Bα VWM mutations were analyzed, a diverse impact on localization was observed, which did not seem to correlate with eIF2B activity. These findings provide key insights into how the eIF2B body assembles and suggest that the body is a fundamental part of the translational regulation via eIF2α phosphorylation. |
format | Online Article Text |
id | pubmed-7948505 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-79485052021-03-19 Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease Norris, Karl Hodgson, Rachel E. Dornelles, Tawni Allen, K. Elizabeth Abell, Ben M. Ashe, Mark P. Campbell, Susan G. J Biol Chem Research Article Eukaryotic initiation factor 2B (eIF2B) serves as a vital control point within protein synthesis and regulates translation initiation in response to cellular stress. Mutations within eIF2B result in the fatal disease, leukoencephalopathy with vanishing white matter (VWM). Previous biochemical studies on VWM mutations have illustrated that changes in the activity of eIF2B poorly correlate with disease severity. This suggests that there may be additional characteristics of eIF2B contributing to VWM pathogenesis. Here, we investigated whether the localization of eIF2B to eIF2B bodies was integral for function and whether this localization could provide insight into the pathogenesis of VWM. We demonstrate that the regulatory subunit, eIF2Bα, is required for the assembly of eIF2B bodies in yeast and that loss of eIF2B bodies correlates with an inability of cells to regulate eIF2B activity. Mutational analysis of eIF2Bα showed that missense mutations that disrupt the regulation of eIF2B similarly disrupt the assembly of eIF2B bodies. In contrast, when eIF2Bα mutations that impact the catalytic activity of eIF2B were analyzed, eIF2B bodies were absent and instead eIF2B localized to small foci, termed microfoci. Fluorescence recovery after photobleaching analysis highlighted that within these microfoci, eIF2 shuttles more slowly indicating that formation of eIF2B bodies correlates with full eIF2B activity. When eIF2Bα VWM mutations were analyzed, a diverse impact on localization was observed, which did not seem to correlate with eIF2B activity. These findings provide key insights into how the eIF2B body assembles and suggest that the body is a fundamental part of the translational regulation via eIF2α phosphorylation. American Society for Biochemistry and Molecular Biology 2021-01-30 /pmc/articles/PMC7948505/ /pubmed/33334879 http://dx.doi.org/10.1074/jbc.RA120.014956 Text en © 2020 The Authors https://creativecommons.org/licenses/by/4.0/This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Research Article Norris, Karl Hodgson, Rachel E. Dornelles, Tawni Allen, K. Elizabeth Abell, Ben M. Ashe, Mark P. Campbell, Susan G. Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease |
title | Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease |
title_full | Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease |
title_fullStr | Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease |
title_full_unstemmed | Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease |
title_short | Mutational analysis of the alpha subunit of eIF2B provides insights into the role of eIF2B bodies in translational control and VWM disease |
title_sort | mutational analysis of the alpha subunit of eif2b provides insights into the role of eif2b bodies in translational control and vwm disease |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7948505/ https://www.ncbi.nlm.nih.gov/pubmed/33334879 http://dx.doi.org/10.1074/jbc.RA120.014956 |
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