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Stabilization of protein synthesis in thermotolerant cells during heat shock. Association of heat shock protein-72 with ribosomal subunits of polysomes
Thermotolerance is defined as the capacity of cells, following a cycle of stress and recovery, to survive a second stress which would otherwise be lethal. Whereas this is a well-documented phenomenon, the mechanisms underlying this protective event remain to be elucidated. Protection of protein synt...
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Published in: | The Journal of biological chemistry 1994-08, Vol.269 (34), p.21803-21811 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Thermotolerance is defined as the capacity of cells, following a cycle of stress and recovery, to survive a second stress
which would otherwise be lethal. Whereas this is a well-documented phenomenon, the mechanisms underlying this protective event
remain to be elucidated. Protection of protein synthesis appears to be one of the components in the induction of thermotolerance
termed "translational thermotolerance." In the present study we show that translational thermotolerance is not the result
of an increase in the concentration of cellular transcripts or the stabilization of preexisting messages, nor the preservation
of the rate of amino acid uptake, synthesis of aminoacyl-tRNA, or protection from degradation of newly synthesized polypeptides.
These results suggest that translational thermotolerance is the consequence of stabilization of translational initiation and/or
polypeptide chain elongation during heat shock. We found that heat shock protein (hsp)-72, the major inducible form of the
hsp-70 family of heat shock proteins, is associated with ribosomal subunits in polysomes of thermotolerant cells during heat
shock. We hypothesize that such interaction is responsible for rescuing translational initiation and/or polypeptide chain
elongation in thermotolerant cells during a subsequent stress. It is possible that hsp-72 on the ribosome is "waiting" for
the nascent polypeptide to emerge from the ribosome. Such interaction may maintain the growing polypeptide in solution during
stress, allowing elongation to continue, and maintaining a constant rate of translation during the stress. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(17)31875-6 |