Sustained AS160 and TBC1D1 phosphorylations in human skeletal muscle 30 min after a single bout of exercise

J Appl Physiol (1985). 2014 Aug 1;117(3):289-96. doi: 10.1152/japplphysiol.00044.2014. Epub 2014 May 29.


Background: phosphorylation of AS160 and TBC1D1 plays an important role for GLUT4 mobilization to the cell surface. The phosphorylation of AS160 and TBC1D1 in humans in response to acute exercise is not fully characterized.

Objective: to study AS160 and TBC1D1 phosphorylation in human skeletal muscle after aerobic exercise followed by a hyperinsulinemic euglycemic clamp.

Design: eight healthy men were studied on two occasions: 1) in the resting state and 2) in the hours after a 1-h bout of ergometer cycling. A hyperinsulinemic euglycemic clamp was initiated 240 min after exercise and in a time-matched nonexercised control condition. We obtained muscle biopsies 30 min after exercise and in a time-matched nonexercised control condition (t = 30) and after 30 min of insulin stimulation (t = 270) and investigated site-specific phosphorylation of AS160 and TBC1D1.

Results: phosphorylation on AS160 and TBC1D1 was increased 30 min after the exercise bout, whereas phosphorylation of the putative upstream kinases, Akt and AMPK, was unchanged compared with resting control condition. Exercise augmented insulin-stimulated phosphorylation on AS160 at Ser(341) and Ser(704) 270 min after exercise. No additional exercise effects were observed on insulin-stimulated phosphorylation of Thr(642) and Ser(588) on AS160 or Ser(237) and Thr(596) on TBC1D1.

Conclusions: AS160 and TBC1D1 phosphorylations were evident 30 min after exercise without simultaneously increased Akt and AMPK phosphorylation. Unlike TBC1D1, insulin-stimulated site-specific AS160 phosphorylation is modified by prior exercise, but these sites do not include Thr(642) and Ser(588). Together, these data provide new insights into phosphorylation of key regulators of glucose transport in human skeletal muscle.

Keywords: AS160; TBC1D1; TBC1D4; endurance exercise; insulin sensitivity; skeletal muscle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / metabolism
  • Adult
  • Biological Transport / physiology
  • Exercise / physiology*
  • GTPase-Activating Proteins / metabolism*
  • Glucose / metabolism
  • Glucose Clamp Technique
  • Glucose Transporter Type 4 / metabolism
  • Humans
  • Insulin / metabolism
  • Male
  • Muscle Contraction / physiology
  • Muscle, Skeletal / metabolism*
  • Phosphorylation / physiology*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Rest / physiology


  • GTPase-Activating Proteins
  • Glucose Transporter Type 4
  • Insulin
  • TBC1D1 protein, human
  • TBC1D4 protein, human
  • Proto-Oncogene Proteins c-akt
  • AMP-Activated Protein Kinases
  • Glucose