Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo
The eukaryotic pre-initiation complex (PIC) bearing the eIF2·GTP·Met-tRNAiMet ternary complex (TC) scans the mRNA for an AUG codon in favorable context. AUG recognition evokes rearrangement of the PIC from an open, scanning to a closed, arrested conformation. Cryo-EM reconstructions of yeast PICs su...
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doaj-83981e19367942159ed87d951631531e2021-05-05T13:15:02ZengeLife Sciences Publications LtdeLife2050-084X2017-02-01610.7554/eLife.22572Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivoJyothsna Visweswaraiah0Alan G Hinnebusch1https://orcid.org/0000-0002-1627-8395Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United StatesLaboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United StatesThe eukaryotic pre-initiation complex (PIC) bearing the eIF2·GTP·Met-tRNAiMet ternary complex (TC) scans the mRNA for an AUG codon in favorable context. AUG recognition evokes rearrangement of the PIC from an open, scanning to a closed, arrested conformation. Cryo-EM reconstructions of yeast PICs suggest remodeling of the interface between 40S protein Rps5/uS7 and eIF2α between open and closed states; however, its importance was unknown. uS7 substitutions disrupting eIF2α contacts favored in the open complex increase initiation at suboptimal sites, and uS7-S223D stabilizes TC binding to PICs reconstituted with a UUG start codon, indicating inappropriate rearrangement to the closed state. Conversely, uS7-D215 substitutions, perturbing uS7-eIF2α interaction in the closed state, confer the opposite phenotypes of hyperaccuracy and (for D215L) accelerated TC dissociation from reconstituted PICs. Thus, remodeling of the uS7/eIF2α interface appears to stabilize first the open, and then the closed state of the PIC to promote accurate AUG selection in vivo.https://elifesciences.org/articles/22572translationinitiationuS7/Rps5eIF2αribosomeyeast |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jyothsna Visweswaraiah Alan G Hinnebusch |
spellingShingle |
Jyothsna Visweswaraiah Alan G Hinnebusch Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo eLife translation initiation uS7/Rps5 eIF2α ribosome yeast |
author_facet |
Jyothsna Visweswaraiah Alan G Hinnebusch |
author_sort |
Jyothsna Visweswaraiah |
title |
Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo |
title_short |
Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo |
title_full |
Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo |
title_fullStr |
Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo |
title_full_unstemmed |
Interface between 40S exit channel protein uS7/Rps5 and eIF2α modulates start codon recognition in vivo |
title_sort |
interface between 40s exit channel protein us7/rps5 and eif2α modulates start codon recognition in vivo |
publisher |
eLife Sciences Publications Ltd |
series |
eLife |
issn |
2050-084X |
publishDate |
2017-02-01 |
description |
The eukaryotic pre-initiation complex (PIC) bearing the eIF2·GTP·Met-tRNAiMet ternary complex (TC) scans the mRNA for an AUG codon in favorable context. AUG recognition evokes rearrangement of the PIC from an open, scanning to a closed, arrested conformation. Cryo-EM reconstructions of yeast PICs suggest remodeling of the interface between 40S protein Rps5/uS7 and eIF2α between open and closed states; however, its importance was unknown. uS7 substitutions disrupting eIF2α contacts favored in the open complex increase initiation at suboptimal sites, and uS7-S223D stabilizes TC binding to PICs reconstituted with a UUG start codon, indicating inappropriate rearrangement to the closed state. Conversely, uS7-D215 substitutions, perturbing uS7-eIF2α interaction in the closed state, confer the opposite phenotypes of hyperaccuracy and (for D215L) accelerated TC dissociation from reconstituted PICs. Thus, remodeling of the uS7/eIF2α interface appears to stabilize first the open, and then the closed state of the PIC to promote accurate AUG selection in vivo. |
topic |
translation initiation uS7/Rps5 eIF2α ribosome yeast |
url |
https://elifesciences.org/articles/22572 |
work_keys_str_mv |
AT jyothsnavisweswaraiah interfacebetween40sexitchannelproteinus7rps5andeif2amodulatesstartcodonrecognitioninvivo AT alanghinnebusch interfacebetween40sexitchannelproteinus7rps5andeif2amodulatesstartcodonrecognitioninvivo |
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1721462117766266880 |