Resistance exercise initiates mechanistic target of rapamycin (mTOR) translocation and protein complex co-localisation in human skeletal muscle

Sci Rep. 2017 Jul 10;7(1):5028. doi: 10.1038/s41598-017-05483-x.

Abstract

The mechanistic target of rapamycin (mTOR) is a central mediator of protein synthesis in skeletal muscle. We utilized immunofluorescence approaches to study mTOR cellular distribution and protein-protein co-localisation in human skeletal muscle in the basal state as well as immediately, 1 and 3 h after an acute bout of resistance exercise in a fed (FED; 20 g Protein/40 g carbohydrate/1 g fat) or energy-free control (CON) state. mTOR and the lysosomal protein LAMP2 were highly co-localised in basal samples. Resistance exercise resulted in rapid translocation of mTOR/LAMP2 towards the cell membrane. Concurrently, resistance exercise led to the dissociation of TSC2 from Rheb and increased in the co-localisation of mTOR and Rheb post exercise in both FED and CON. In addition, mTOR co-localised with Eukaryotic translation initiation factor 3 subunit F (eIF3F) at the cell membrane post-exercise in both groups, with the response significantly greater at 1 h of recovery in the FED compared to CON. Collectively our data demonstrate that cellular trafficking of mTOR occurs in human muscle in response to an anabolic stimulus, events that appear to be primarily influenced by muscle contraction. The translocation and association of mTOR with positive regulators (i.e. Rheb and eIF3F) is consistent with an enhanced mRNA translational capacity after resistance exercise.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Cell Membrane / metabolism
  • Dietary Carbohydrates / administration & dosage
  • Dietary Proteins / administration & dosage
  • Eukaryotic Initiation Factor-3 / metabolism*
  • Female
  • Humans
  • Lysosomal-Associated Membrane Protein 2 / metabolism*
  • Male
  • Muscle Contraction
  • Muscle, Skeletal / metabolism*
  • Protein Binding
  • Protein Transport
  • Ras Homolog Enriched in Brain Protein / metabolism*
  • Resistance Training / methods*
  • TOR Serine-Threonine Kinases / metabolism*
  • Tuberous Sclerosis Complex 2 Protein / metabolism*
  • Young Adult

Substances

  • Dietary Carbohydrates
  • Dietary Proteins
  • EIF3F protein, human
  • Eukaryotic Initiation Factor-3
  • LAMP2 protein, human
  • Lysosomal-Associated Membrane Protein 2
  • RHEB protein, human
  • Ras Homolog Enriched in Brain Protein
  • TSC2 protein, human
  • Tuberous Sclerosis Complex 2 Protein
  • MTOR protein, human
  • TOR Serine-Threonine Kinases