Early Time Course of Akt Phosphorylation after Endurance and Resistance Exercise

Camera, Donny M.; Edge, Johann; Short, Michael; Hawley, John A.; Coffey, Vernon G.

doi:10.1249/mss.0b013e3181d964e4

Cited by 129 publications

(126 citation statements)

References 37 publications

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“…The noted increase in ERK 1/2 phosphorylation is consistent with our previous report, which suggests that harvesting multiple biopsy samples from one incision site may elicit an inflammatory response that might influence intracellular signaling (13). Changes in Akt, mTOR, rpS6, and eEF2 phosphorylation are similar to those in other studies and are consistent with an upregulation of mRNA translation initiation, elongation, and increased MPS after exercise (1,15,16,(47)(48)(49). It is important to note that we were unable to detect significant differences in the phosphorylation of any critical mTORC1 intracellular signaling protein between the dietary treatment groups, despite the differences observed in MPS.…”

Section: Discussionsupporting

confidence: 90%

“…The discrepant observations regarding the influence of endurance-type exercise and feeding on mTORC1 intracellular signaling may be attributed to between-study differences in exercise intensity and duration, in the training state of the study volunteers, and in the timing of the muscle biopsy collections during recovery (48,(50)(51)(52). In the current study, moderate steady state exercise coupled with EAA supplementation increased Akt, mTOR, rpS6, and ERK 1/2 and reduced eEF2 phosphorylation.…”

Section: Discussioncontrasting

confidence: 59%

“…Some studies have shown that endurance exercise alone or combined with feeding stimulates mTORC1 intracellular signaling (16,(47)(48)(49), although other investigations have shown little or no effect of endurance exercise with or without nutrition 1 All values are means 6 SEMs; n = 8. PE phosphorylation data are expressed relative to total protein and presented as fold changes compared with baseline (time 0) for the L-EAA and EAA trials.…”

Section: Discussionmentioning

confidence: 99%

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Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis

Pasiakos

McClung²,

McClung³

et al. 2011

The American Journal of Clinical Nutrition

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Background: The effects of essential amino acid (EAA) supplementation during moderate steady state (ie, endurance) exercise on postexercise skeletal muscle metabolism are not well described, and the potential role of supplemental leucine on muscle protein synthesis (MPS) and associated molecular responses remains to be elucidated.Objective: This randomized crossover study examined whether EAA supplementation with 2 different concentrations of leucine affected post-steady state exercise MPS, whole-body protein turnover, and mammalian target of rapamycin 1 (mTORC1) intracellular signaling. Design: Eight adults completed 2 separate bouts of cycle ergometry [60 min, 60% VO 2 peak (peak oxygen uptake)]. Isonitrogenous (10 g EAA) drinks with different leucine contents [leucine-enriched (L)-EAA, 3.5 g leucine; EAA, 1.87 g leucine] were consumed during exercise. MPS and whole-body protein turnover were determined by using primed continuous infusions of [ 2 H 5 ]phenylalanine and [1-13 C]leucine. Multiplex and immunoblot analyses were used to quantify mTORC1 signaling. Results: MPS was 33% greater (P , 0.05) after consumption of L-EAA (0.08 6 0.01%/h) than after consumption of EAA (0.06 6 0.01%/h). Whole-body protein breakdown and synthesis were lower (P , 0.05) and oxidation was greater (P , 0.05) after consumption of L-EAA than after consumption of EAA. Regardless of dietary treatment, multiplex analysis indicated that Akt and mammalian target of rapamycin phosphorylation were increased (P , 0.05) 30 min after exercise. Immunoblot analysis indicated that phosphorylation of ribosomal protein S6 and extracellular-signal regulated protein kinase increased (P , 0.05) and phosphorylation of eukaryotic elongation factor 2 decreased (P , 0.05) after exercise but was not affected by dietary treatment. Conclusion: These findings suggest that increasing the concentration of leucine in an EAA supplement consumed during steady state exercise elicits a greater MPS response during recovery. This trial is registered at clinicaltrials.gov as NCT01366924.Am J Clin Nutr 2011;94:809-18.

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Section: Discussionsupporting

confidence: 90%

Section: Discussioncontrasting

confidence: 59%

Section: Discussionmentioning

confidence: 99%

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Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis

Pasiakos

McClung²,

McClung³

et al. 2011

The American Journal of Clinical Nutrition

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“…It should be noted that in the current study, a significant but temporal increase in mTORC1 activity was observed in response to EE alone. Immediate mTORC1 signaling response is not RE specific, and EE also activates mTORC1 signaling (7,18). In the present study, EE also increased phosphorylation of Akt, an upstream stimulator of mTORC1.…”

Section: Discussionsupporting

confidence: 48%

The order of concurrent endurance and resistance exercise modifies mTOR signaling and protein synthesis in rat skeletal muscle

Ogasawara

Sato

Matsutani

et al. 2014

American Journal of Physiology-Endocrinology and Metabolism

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Ogasawara R, Sato K, Matsutani K, Nakazato K, Fujita S. The order of concurrent endurance and resistance exercise modifies mTOR signaling and protein synthesis in rat skeletal muscle. Am J Physiol Endocrinol Metab 306: E1155-E1162, 2014. First published April 1, 2014; doi:10.1152/ajpendo.00647.2013.-Concurrent training, a combination of endurance (EE) and resistance exercise (RE) performed in succession, may compromise the muscle hypertrophic adaptations induced by RE alone. However, little is known about the molecular signaling interactions underlying the changes in skeletal muscle adaptation during concurrent training. Here, we used an animal model to investigate whether EE before or after RE affects the molecular signaling associated with muscle protein synthesis, specifically the interaction between RE-induced mammalian target of rapamycin complex 1 (mTORC1) signaling and EE-induced AMP-activated protein kinase (AMPK) signaling. Male Sprague-Dawley rats were divided into five groups: an EE group (treadmill, 25 m/min, 60 min), an RE group (maximum isometric contraction via percutaneous electrical stimulation for 3 ϫ 10 s, 5 sets), an EE before RE group, an EE after RE group, and a nonexercise control group. Phosphorylation of p70S6K, a marker of mTORC1 activity, was significantly increased 3 h after RE in both the EE before RE and EE after RE groups, but the increase was smaller in latter. Furthermore, protein synthesis was greatly increased 6 h after RE in the EE before RE group. Increases in the phosphorylation of AMPK and Raptor were observed only in the EE after RE group. Akt and mTOR phosphorylation were increased in both groups, with no between-group differences. Our results suggest that the last bout of exercise dictates the molecular responses and that mTORC1 signaling induced by any prior bout of RE may be downregulated by a subsequent bout of EE. concurrent exercise; mammalian target of rapamycin complex 1; adenosine 5=-monophosphate-activated protein kinase; resistance exercise; endurance exercise SKELETAL MUSCLE IS A HIGHLY PLASTIC TISSUE that adapts differently to different stimuli, including various types of muscle contractions. Chronic muscle contraction induces diverse metabolic and morphological adaptations because of the cumulative effects of repeated bouts of exercise, and certain molecular and cellular responses lead to specific adaptations (3, 10, 47). The well-known adaptive features of chronic muscle contraction include muscle hypertrophy and increased strength. These features are induced by high-intensity muscle contraction, such as that involved in resistance exercises (RE) (50, 52). Other typical adaptations are increases in oxidative capacity and glucose uptake, which are induced by low-intensity, highvolume muscle contraction, such as that observed during endurance exercises (EE) (5, 28, 53).Concurrent training, a combination of EE and RE in succession, is used widely in exercise prescription to simultaneously improve muscular strength and cardiovascular function. Interestingly, ac...

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“…This is unsurprising given the necessity to initiate and increase gene translation and protein expression responses that ultimately form the basis of adaptation and muscle remodelling to exercise (Camera et al, 2010). Increases in mTOR, rpS6 and 4E-BP1 phosphorylation have been reported when protein was ingested following endurance exercise compared with a carbohydrate-fat beverage (Rowlands et al, 2015) or a nonenergetic placebo (Ivy et al, 2008).…”

Section: Reduced Energy Availabilitymentioning

confidence: 99%

Effects of skeletal muscle energy availability on protein turnover responses to exercise

Smiles

Hawley

Camera

2016

Journal of Experimental Biology

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Skeletal muscle adaptation to exercise training is a consequence of repeated contraction-induced increases in gene expression that lead to the accumulation of functional proteins whose role is to blunt the homeostatic perturbations generated by escalations in energetic demand and substrate turnover. The development of a specific 'exercise phenotype' is the result of new, augmented steady-state mRNA and protein levels that stem from the training stimulus (i.e. endurance or resistance based). Maintaining appropriate skeletal muscle integrity to meet the demands of training (i.e. increases in myofibrillar and/or mitochondrial protein) is regulated by cyclic phases of synthesis and breakdown, the rate and turnover largely determined by the protein's half-life. Cross-talk among several intracellular systems regulating protein synthesis, breakdown and folding is required to ensure protein equilibrium is maintained. These pathways include both proteasomal and lysosomal degradation systems (ubiquitin-mediated and autophagy, respectively) and the protein translational and folding machinery. The activities of these cellular pathways are bioenergetically expensive and are modified by intracellular energy availability (i.e. macronutrient intake) and the 'training impulse' (i.e. summation of the volume, intensity and frequency). As such, exercisenutrient interactions can modulate signal transduction cascades that converge on these protein regulatory systems, especially in the early post-exercise recovery period. This review focuses on the regulation of muscle protein synthetic response-adaptation processes to divergent exercise stimuli and how intracellular energy availability interacts with contractile activity to impact on muscle remodelling.

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Early Time Course of Akt Phosphorylation after Endurance and Resistance Exercise

Cited by 129 publications

References 37 publications

Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis

Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis

The order of concurrent endurance and resistance exercise modifies mTOR signaling and protein synthesis in rat skeletal muscle

Effects of skeletal muscle energy availability on protein turnover responses to exercise

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