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Translocation and protein complex co-localization of mTOR is associated with postprandial myofibrillar protein synthesis at rest and after endurance exercise.

Publication ,  Journal Article
Abou Sawan, S; van Vliet, S; Parel, JT; Beals, JW; Mazzulla, M; West, DWD; Philp, A; Li, Z; Paluska, SA; Burd, NA; Moore, DR
Published in: Physiological reports
March 2018

Translocation and colocalization of mechanistic target of rapamycin complex 1 (mTORC1) with regulatory proteins represents a critical step in translation initiation of protein synthesis in vitro. However, mechanistic insight into the control of postprandial skeletal muscle protein synthesis rates at rest and after an acute bout of endurance exercise in humans is lacking. In crossover trials, eight endurance-trained men received primed-continuous infusions of L-[ring-2 H5 ]phenylalanine and consumed a mixed-macronutrient meal (18 g protein, 60 g carbohydrates, 17 g fat) at rest (REST) and after 60 min of treadmill running at 70% VO2peak (EX). Skeletal muscle biopsies were collected to measure changes in phosphorylation and colocalization in the mTORC1-pathway, in addition to rates of myofibrillar (MyoPS) and mitochondrial (MitoPS) protein synthesis. MyoPS increased (P < 0.05) above fasted in REST (~2.1-fold) and EX (~twofold) during the 300 min postprandial period, with no corresponding changes in MitoPS (P > 0.05). TSC2/Rheb colocalization decreased below fasted at 60 and 300 min after feeding in REST and EX (P < 0.01). mTOR colocalization with Rheb increased above fasted at 60 and 300 min after feeding in REST and EX (P < 0.01), which was consistent with an increased phosphorylation 4E-BP1Thr37/46 and rpS6ser240/244 at 60 min. Our data suggest that MyoPS, but not MitoPS, is primarily nutrient responsive in trained young men at rest and after endurance exercise. The postprandial increase in MyoPS is associated with an increase in mTOR/Rheb colocalization and a reciprocal decrease in TSC2/Rheb colocalization and thus likely represent important regulatory events for in vivo skeletal muscle myofibrillar mRNA translation in humans.

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Published In

Physiological reports

DOI

EISSN

2051-817X

ISSN

2051-817X

Publication Date

March 2018

Volume

6

Issue

5

Related Subject Headings

  • Tuberous Sclerosis Complex 2 Protein
  • Protein Transport
  • Protein Processing, Post-Translational
  • Postprandial Period
  • Physical Conditioning, Human
  • Phosphorylation
  • Phosphoproteins
  • Phenylalanine
  • Muscle, Skeletal
  • Mitochondria, Muscle
 

Citation

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Abou Sawan, S., van Vliet, S., Parel, J. T., Beals, J. W., Mazzulla, M., West, D. W. D., … Moore, D. R. (2018). Translocation and protein complex co-localization of mTOR is associated with postprandial myofibrillar protein synthesis at rest and after endurance exercise. Physiological Reports, 6(5). https://doi.org/10.14814/phy2.13628
Abou Sawan, Sidney, Stephan van Vliet, Justin T. Parel, Joseph W. Beals, Michael Mazzulla, Daniel W. D. West, Andrew Philp, et al. “Translocation and protein complex co-localization of mTOR is associated with postprandial myofibrillar protein synthesis at rest and after endurance exercise.Physiological Reports 6, no. 5 (March 2018). https://doi.org/10.14814/phy2.13628.
Abou Sawan S, van Vliet S, Parel JT, Beals JW, Mazzulla M, West DWD, et al. Translocation and protein complex co-localization of mTOR is associated with postprandial myofibrillar protein synthesis at rest and after endurance exercise. Physiological reports. 2018 Mar;6(5).
Abou Sawan, Sidney, et al. “Translocation and protein complex co-localization of mTOR is associated with postprandial myofibrillar protein synthesis at rest and after endurance exercise.Physiological Reports, vol. 6, no. 5, Mar. 2018. Epmc, doi:10.14814/phy2.13628.
Abou Sawan S, van Vliet S, Parel JT, Beals JW, Mazzulla M, West DWD, Philp A, Li Z, Paluska SA, Burd NA, Moore DR. Translocation and protein complex co-localization of mTOR is associated with postprandial myofibrillar protein synthesis at rest and after endurance exercise. Physiological reports. 2018 Mar;6(5).

Published In

Physiological reports

DOI

EISSN

2051-817X

ISSN

2051-817X

Publication Date

March 2018

Volume

6

Issue

5

Related Subject Headings

  • Tuberous Sclerosis Complex 2 Protein
  • Protein Transport
  • Protein Processing, Post-Translational
  • Postprandial Period
  • Physical Conditioning, Human
  • Phosphorylation
  • Phosphoproteins
  • Phenylalanine
  • Muscle, Skeletal
  • Mitochondria, Muscle