Abstract:
:In earlier studies it was shown that the mammalian translation system is highly organized in vivo and that the intermediates in the process, aminoacyl-tRNAs, are channeled--i.e., they are directly transferred from the aminoacyl-tRNA synthetases to the elongation factor to the ribosomes without dissociating into the cellular fluid. Here, we examine whether spent tRNAs leaving the ribosome enter the fluid phase or are transferred directly to their cognate aminoacyl-tRNA synthetases to complete a channeled tRNA cycle. Using a permeabilized CHO cell system that closely mimics living cells, we find that there is no leakage of endogenous tRNA during many cycles of translation, and protein synthesis remains linear during this period, even though free aminoacyl-tRNA is known to rapidly equilibrate between the inside and outside of these cells. We also find that exogenous tRNA and periodate-oxidized tRNA have no effect on protein synthesis in this system, indicating that they do not enter the translation machinery, despite the fact that exogenous tRNA rapidly distributes throughout the cells. Furthermore, most of the cellular aminoacyl-tRNA synthetases function only with endogenous tRNAs, although a portion can use exogenous tRNA molecules. However, aminoacylation of these exogenous tRNAs is strongly inhibited by oxidized tRNA; this inhibitor has no effect on endogenous aminoacylation. On the basis of these and the earlier observations, we conclude that endogenous tRNA is never free of the protein synthetic machinery at any stage of the translation process and, consequently, that there is a channeled tRNA cycle during protein synthesis in mammalian cells.
journal_name
Proc Natl Acad Sci U S Aauthors
Stapulionis R,Deutscher MPdoi
10.1073/pnas.92.16.7158subject
Has Abstractpub_date
1995-08-01 00:00:00pages
7158-61issue
16eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::Rod-shaped "ghosts" that are free of murein have been isolated from E. coli. The shape of these "ghosts" is maintained by a unit membrane soluble in sodium dodecyl sulfate. Ghosts consist of about 20-30% phospholipid (almost exclusively phosphatidylethanolamine) and 50-60% protein; a large fraction of the remaining ma...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1973-07-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.15.7114
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1986-07-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2020-01-28 00:00:00
abstract::The pathogenic species of Yersinia contain the transcriptional regulator RovA. In Yersinia pseudotuberculosis and Yersinia enterocolitica, RovA regulates expression of the invasion factor invasin (inv), which mediates translocation across the intestinal epithelium. A Y. enterocolitica rovA mutant has a significant dec...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2006-09-05 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1994-10-11 00:00:00
abstract::Past research found that the ingestion of glucose can enhance self-control. It has been widely assumed that basic physiological processes underlie this effect. We hypothesized that the effect of glucose also depends on people's theories about willpower. Three experiments, both measuring (experiment 1) and manipulating...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2013-09-10 00:00:00
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更新日期:2006-02-21 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2002-10-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
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更新日期:1996-10-29 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1613031113
更新日期:2016-12-06 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2018-03-20 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1984-02-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.12.5111
更新日期:1991-06-15 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2005-12-06 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2016-08-02 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2015-06-02 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2008-09-30 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2014-08-12 00:00:00
abstract::For a number of viruses, oligomerization is a critical component of envelope processing and surface expression. Previously, we reported that a synthetic peptide (DP-107) corresponding to the putative leucine zipper region (aa 553-590) of the transmembrane protein (gp41) of human immunodeficiency virus type 1 (HIV-1) e...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1994-12-20 00:00:00
abstract::The Arabidopsis thaliana AtHKT1 protein, a Na(+)/K(+) transporter, is capable of mediating inward Na(+) currents in Xenopus laevis oocytes and K(+) uptake in Escherichia coli. HKT1 proteins are members of a superfamily of K(+) transporters. These proteins have been proposed to contain eight transmembrane segments and ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2001-05-22 00:00:00
abstract::The transforming protein of avian sarcoma virus UR2, p68v-ros, has an associated tyrosine-specific protein kinase activity similar to that of p60v-src and several other oncogene products. However, this activity has not been linked unequivocally to transformation, and the physiological action of these proteins remains ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1984-05-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1991-11-15 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1983-02-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2007-11-20 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.7.2760
更新日期:1995-03-28 00:00:00
abstract::We have analyzed the cell cycle regulation of human cyclin-dependent kinase 2 (CDK2), a protein closely related to the cell cycle-regulatory protein kinase CDC2. We find that CDK2 activity, like that of CDC2, oscillates during the cell cycle in cultured mammalian fibroblasts. Unlike CDC2 activity (which peaks during m...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.7.2824
更新日期:1992-04-01 00:00:00