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The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit

The delivery of Met-tRNA(i) to the 40S ribosomal subunit is thought to occur by way of a ternary complex (TC) comprising eIF2, GTP and Met-tRNA(i). We have generated from purified human proteins a stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported in y...

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Detalles Bibliográficos
Autores principales: Sokabe, Masaaki, Fraser, Christopher S., Hershey, John W. B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2012
Materias:
RNA
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258154/
https://www.ncbi.nlm.nih.gov/pubmed/21940399
http://dx.doi.org/10.1093/nar/gkr772
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author Sokabe, Masaaki
Fraser, Christopher S.
Hershey, John W. B.
author_facet Sokabe, Masaaki
Fraser, Christopher S.
Hershey, John W. B.
author_sort Sokabe, Masaaki
collection PubMed
description The delivery of Met-tRNA(i) to the 40S ribosomal subunit is thought to occur by way of a ternary complex (TC) comprising eIF2, GTP and Met-tRNA(i). We have generated from purified human proteins a stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported in yeast and plants. A human MFC free of the ribosome also is detected in HeLa cells and rabbit reticulocytes, indicating that it exists in vivo. In vitro, the MFC-GTP binds Met-tRNA(i) and delivers the tRNA to the ribosome at the same rate as the TC. However, MFC-GDP shows a greatly reduced affinity to Met-tRNA(i) compared to that for eIF2-GDP, suggesting that MFC components may play a role in the release of eIF2-GDP from the ribosome following AUG recognition. Since an MFC–Met-tRNA(i) complex is detected in cell lysates, it may be responsible for Met-tRNA(i)–40S ribosome binding in vivo, possibly together with the TC. However, the MFC protein components also bind individually to 40S ribosomes, creating the possibility that Met-tRNA(i) might bind directly to such 40S-factor complexes. Thus, three distinct pathways for Met-tRNA(i) delivery to the 40S ribosomal subunit are identified, but which one predominates in vivo remains to be elucidated.
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spelling pubmed-32581542012-01-17 The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit Sokabe, Masaaki Fraser, Christopher S. Hershey, John W. B. Nucleic Acids Res RNA The delivery of Met-tRNA(i) to the 40S ribosomal subunit is thought to occur by way of a ternary complex (TC) comprising eIF2, GTP and Met-tRNA(i). We have generated from purified human proteins a stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported in yeast and plants. A human MFC free of the ribosome also is detected in HeLa cells and rabbit reticulocytes, indicating that it exists in vivo. In vitro, the MFC-GTP binds Met-tRNA(i) and delivers the tRNA to the ribosome at the same rate as the TC. However, MFC-GDP shows a greatly reduced affinity to Met-tRNA(i) compared to that for eIF2-GDP, suggesting that MFC components may play a role in the release of eIF2-GDP from the ribosome following AUG recognition. Since an MFC–Met-tRNA(i) complex is detected in cell lysates, it may be responsible for Met-tRNA(i)–40S ribosome binding in vivo, possibly together with the TC. However, the MFC protein components also bind individually to 40S ribosomes, creating the possibility that Met-tRNA(i) might bind directly to such 40S-factor complexes. Thus, three distinct pathways for Met-tRNA(i) delivery to the 40S ribosomal subunit are identified, but which one predominates in vivo remains to be elucidated. Oxford University Press 2012-01 2011-09-22 /pmc/articles/PMC3258154/ /pubmed/21940399 http://dx.doi.org/10.1093/nar/gkr772 Text en © The Author(s) 2011. Published by Oxford University Press. http://creativecommons.org/licenses/by-nc/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle RNA
Sokabe, Masaaki
Fraser, Christopher S.
Hershey, John W. B.
The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit
title The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit
title_full The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit
title_fullStr The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit
title_full_unstemmed The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit
title_short The human translation initiation multi-factor complex promotes methionyl-tRNA(i) binding to the 40S ribosomal subunit
title_sort human translation initiation multi-factor complex promotes methionyl-trna(i) binding to the 40s ribosomal subunit
topic RNA
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258154/
https://www.ncbi.nlm.nih.gov/pubmed/21940399
http://dx.doi.org/10.1093/nar/gkr772
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