Effects of Leucine Ingestion and Contraction on the Sestrin/GATOR2 Pathway and mTORC1 Activation in Rat Fast-Twitch muscle.
amino acid sensing
dose-dependence
leucine sensor
skeletal muscle
time course
Journal
The Journal of nutrition
ISSN: 1541-6100
Titre abrégé: J Nutr
Pays: United States
ID NLM: 0404243
Informations de publication
Date de publication:
08 2023
08 2023
Historique:
received:
02
04
2023
revised:
05
06
2023
accepted:
13
06
2023
medline:
11
8
2023
pubmed:
17
6
2023
entrez:
16
6
2023
Statut:
ppublish
Résumé
Leucine activates the mechanistic/mammalian target of rapamycin complex 1 (mTORC1) in mammalian skeletal muscle. Recent studies have shown that Sestrin, a leucine sensor, might play a role in this process. However, it remains unknown whether Sestrin dissociates from GATOR2 in a dose- and time-dependent manner and whether an acute bout of muscle contraction augments this dissociation. This study aimed to examine the effects of leucine ingestion and muscle contraction on the interaction between Sestrin1/2 and GATOR2 and on mTORC1 activation. Male Wistar rats were randomly assigned to control (C), leucine 3 (L3), or leucine 10 (L10) groups. Intact gastrocnemius muscles were subjected to 30 repetitive unilateral contractions. The L3 and L10 groups were then orally administered 3 and 10 mmol/kg body weight of L-leucine 2 h after the end of the contractions, respectively. Blood and muscle samples were collected 30, 60, or 120 min after the administration. The blood and muscle leucine concentrations increased in a dose-dependent manner. The ratio of phosphorylated ribosomal protein S6 kinase (S6K) to total S6K (which indicates mTORC1 signaling activation) was markedly increased by muscle contraction and increased in a dose-dependent manner only in rested muscle. Leucine ingestion but not muscle contraction increased Sestrin1 dissociation from GATOR2 and Sestrin2 association with GATOR2. A negative relationship was observed between the blood and muscle leucine concentrations and the Sestrin1 association with GATOR2. The results suggest that Sestrin1, but not Sestrin2, regulates leucine-related mTORC1 activation via its dissociation from GATOR2 and that acute exercise-induced mTORC1 activation involves pathways other than the leucine-related Sestrin1/GATOR2 pathway.
Sections du résumé
BACKGROUND
Leucine activates the mechanistic/mammalian target of rapamycin complex 1 (mTORC1) in mammalian skeletal muscle. Recent studies have shown that Sestrin, a leucine sensor, might play a role in this process. However, it remains unknown whether Sestrin dissociates from GATOR2 in a dose- and time-dependent manner and whether an acute bout of muscle contraction augments this dissociation.
OBJECTIVE
This study aimed to examine the effects of leucine ingestion and muscle contraction on the interaction between Sestrin1/2 and GATOR2 and on mTORC1 activation.
METHODS
Male Wistar rats were randomly assigned to control (C), leucine 3 (L3), or leucine 10 (L10) groups. Intact gastrocnemius muscles were subjected to 30 repetitive unilateral contractions. The L3 and L10 groups were then orally administered 3 and 10 mmol/kg body weight of L-leucine 2 h after the end of the contractions, respectively. Blood and muscle samples were collected 30, 60, or 120 min after the administration.
RESULTS
The blood and muscle leucine concentrations increased in a dose-dependent manner. The ratio of phosphorylated ribosomal protein S6 kinase (S6K) to total S6K (which indicates mTORC1 signaling activation) was markedly increased by muscle contraction and increased in a dose-dependent manner only in rested muscle. Leucine ingestion but not muscle contraction increased Sestrin1 dissociation from GATOR2 and Sestrin2 association with GATOR2. A negative relationship was observed between the blood and muscle leucine concentrations and the Sestrin1 association with GATOR2.
CONCLUSIONS
The results suggest that Sestrin1, but not Sestrin2, regulates leucine-related mTORC1 activation via its dissociation from GATOR2 and that acute exercise-induced mTORC1 activation involves pathways other than the leucine-related Sestrin1/GATOR2 pathway.
Identifiants
pubmed: 37328110
pii: S0022-3166(23)72417-6
doi: 10.1016/j.tjnut.2023.06.011
pii:
doi:
Substances chimiques
Mechanistic Target of Rapamycin Complex 1
EC 2.7.11.1
Leucine
GMW67QNF9C
Sestrins
0
TOR Serine-Threonine Kinases
EC 2.7.11.1
Nuclear Proteins
0
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
2228-2236Informations de copyright
Copyright © 2023 American Society for Nutrition. Published by Elsevier Inc. All rights reserved.