The putative leucine sensor Sestrin2 is hyperphosphorylated by acute resistance exercise but not protein ingestion in human skeletal muscle
Dietary protein and resistance exercise (RE) are both potent stimuli of the mammalian target of rapamycin complex 1 (mTORC1). Sestrins1, 2, 3 are multifunctional proteins that regulate mTORC1, stimulate autophagy and alleviate oxidative stress. Of this family, Sestrin2 is a putative leucine sensor implicated in mTORC1 and AMP-dependent protein kinase (AMPK) regulation. There is currently no data examining the responsiveness of Sestrin2 to dietary protein ingestion, with or without RE.
In Study 1, 16 males ingested either 10 or 20 g of milk protein concentrate (MPC) with muscle biopsies collected pre, 90 and 210 min post-beverage consumption. In Study 2, 20 males performed a bout of RE immediately followed by the consumption of 9 g of MPC or carbohydrate placebo. Analysis of Sestrins, AMPK and antioxidant responses was examined.
Dietary protein ingestion did not result in Sestrin2 mobility shift. After RE, Sestrin2 phosphorylation state was significantly altered and was not further modified by post-exercise protein or carbohydrate ingestion. With RE, AMPK phosphorylation remained stable, while the mRNA expressions of several antioxidants were upregulated.
Dietary protein ingestion did not affect the signalling by the family of Sestrins. With RE, Sestrin2 was hyperphosphorylated, with no further evidence of a relationship to AMPK signalling.
KeywordsAmino acid Resistance exercise Mammalian target of rapamycin Oxidative stress Antioxidant Sestrins Hyperphosphorylation
- 4E BP1
Eukaryotic initiation factor 4E-binding protein 1
AMP-activated protein kinase
Analysis of variance
GTPase-activating protein activity towards Rags
Human embryonic kidney cells 293
Heme oxygenase 1
Kelch-like ECH-associated protein
Milk protein concentrate
Muscle protein synthesis
Mammalian target of rapamycin complex 1
Nuclear factor (erythroid-derived 2)-like 2
Ribosomal protein S6 kinase 1
Reactive oxygen species
Ribosomal protein S6
Standard error of mean
The study was funded by AgResearch (through Strategic Science Investment Fund contracts A19079 and A21246). MPGB is a current employee of AgResearch.
NZ, CJM and DCS designed the study; NZ and RFD conducted experiments; NZ, BS and TLM analysed data; NZ, CJM and DCS drafted manuscript; NZ, RFD, MPGB, BS, TLM, CJM and DCS critically evaluated and contributed to the manuscript.
- Drummond MJ, Glynn EL, Fry CS, Timmerman KL, Volpi E, Rasmussen BB (2010) An increase in essential amino acid availability upregulates amino acid transporter expression in human skeletal muscle. Am J Physiol Endocrinol Metab 298:E1011–E1018. https://doi.org/10.1152/ajpendo.00690.2009 CrossRefPubMedPubMedCentralGoogle Scholar
- Norton LE, Layman DK, Bunpo P, Anthony TG, Brana DV, Garlick PJ (2009) The leucine content of a complete meal directs peak activation but not duration of skeletal muscle protein synthesis and mammalian target of rapamycin signaling in rats. J Nutr 139:1103–1109. https://doi.org/10.3945/jn.108.103853 CrossRefPubMedGoogle Scholar
- Park JW, Choi JY, Hong SA et al (2017) Exercise induced upregulation of glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modifier subunit gene expression in Thoroughbred horses. Asian Australas J Anim Sci 30:728–735. https://doi.org/10.5713/ajas.16.0776 CrossRefPubMedPubMedCentralGoogle Scholar
- Pennings B, Koopman R, Beelen M, Senden JM, Saris WH, van Loon LJ (2011) Exercising before protein intake allows for greater use of dietary protein-derived amino acids for de novo muscle protein synthesis in both young and elderly men. Am J Clin Nutr 93:322–331. https://doi.org/10.3945/ajcn.2010.29649 CrossRefPubMedGoogle Scholar
- Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM (2009) Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol (1985) 107:987–992. https://doi.org/10.1152/japplphysiol.00076.2009 CrossRefGoogle Scholar