Increased insulin-stimulated Akt pSer473 and cytosolic SHP2 protein abundance in human skeletal muscle following acute exercise and short-term training.
The purpose of the present study was to determine in human skeletal muscle whether a single exercise bout and 7 days of consecutive endurance (cycling) training 1) increased insulin-stimulated Akt pSer(473) and 2) altered the abundance of the protein tyrosine phosphatases (PTPases), PTP1B and SHP2. In healthy, untrained men (n = 8; 24 +/- 1 yr), glucose infusion rate during a hyperinsulinemic euglycemic clamp, when compared with untrained values, was not improved 24 h following a single 60-min bout of endurance cycling but was significantly increased ( approximately 30%; P < 0.05) 24 h following completion of 7 days of exercise training. Insulin-stimulated Akt pSer(473) was approximately 50% higher (P < 0.05) 24 h following the acute bout of exercise, with this effect remaining after 7 days of training (P < 0.05). Insulin-stimulated insulin receptor and insulin receptor substrate-1 tyrosine phosphorylation were not altered 24 h after acute exercise and short-term training. Insulin did not acutely regulate the localization of the PTPases, PTP1B or SHP2, although cytosolic protein abundance of SHP2 was increased (P < 0.05; main effect) 24 h following acute exercise and short-term training. In conclusion, insulin-sensitive Akt pSer(473) and cytosolic SHP2 protein abundance are higher after acute exercise and short-term training, and this effect appears largely due to the residual effects of the last bout of prior exercise. The significance of exercise-induced alterations in cytosolic SHP2 and insulin-stimulated Akt pSer(473) on the improvement in insulin sensitivity requires further elucidation.
Wadley
Glenn D
GD
1School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia. gdwadley@unimelb.edu.au
Konstantopoulos
Nicky
N
Macaulay
Lance
L
Howlett
Kirsten F
KF
Garnham
Andrew
A
Hargreaves
Mark
M
Cameron-Smith
David
D
D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000328:Adult; D003600:Cytosol / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000008:administration & dosage*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*
D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D051057:Proto-Oncogene Proteins c-akt; C516607:PTPN1 protein, human; C516724:PTPN11 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases