Document Detail


The unfolded protein response is triggered following a single, unaccustomed resistance-exercise bout.
MedLine Citation:
PMID:  25009220     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Endoplasmic reticulum (ER) stress results from an imbalance between the abundance of synthesized proteins and the folding capacity of the ER. In response, the unfolded protein response (UPR), attempts to restore ER function by attenuating protein synthesis and inducing chaperone expression. Resistance exercise (RE) stimulates protein synthesis; however, a post-exercise accumulation of unfolded proteins may activate the UPR. Aging may impair protein folding and the accumulation of oxidized and misfolded proteins may stimulate the UPR at rest in aged muscle. Eighteen younger (Y; n=9, 21±3 y) and older (O; n=9, 70±4 y) untrained men completed a single unilateral bout of RE using the knee extensors (4 sets of 10 repetitions at 75%-1RM on the leg press, leg extension) to determine if the UPR is increased in resting, aged muscle and if RE stimulates the UPR. Muscle biopsies were taken from the non-exercised and exercised vastus lateralis at 3, 24 and 48 h post-exercise. Age did not affect any of the proteins and transcripts related to the UPR. GRP78 and PERK proteins were increased at 48 h post-exercise while IRE1α was elevated at 24 and 48 h. Despite elevated protein, GRP78 and PERK mRNA were unchanged; however, IRE1α mRNA was increased at 24 h post-exercise. ATF6 mRNA increased at 24 and 48 h while ATF4, CHOP and GADD34 mRNA were unchanged. This data suggests RE activates specific pathways of the UPR (ATF6/IRE1α), while PERK/eIF2α/CHOP is not. In conclusion, acute RE results in UPR activation irrespective of age.
Authors:
Daniel I Ogborn; Bryon R McKay; Justin D Crane; Gianni Parise; Mark A Tarnopolsky
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-7-9
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  -     ISSN:  1522-1490     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2014 Jul 
Date Detail:
Created Date:  2014-7-10     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2013, American Journal of Physiology - Regulatory, Integrative and Comparative Physiology.
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