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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...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2012
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Materias: | |
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. |
format | Online Article Text |
id | pubmed-3258154 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
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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