Invited review: Regulation of skeletal muscle GLUT-4 expression by exercise.
The amount of GLUT-4 protein is a primary factor in determining the maximal rate of glucose transport into skeletal muscle. Therefore, it is important that we understand how exercise regulates GLUT-4 expression so that therapeutic strategies can be designed to increase muscle glucose disposal as a treatment for diabetes. Muscle contraction increases the rates of GLUT-4 transcription and translation. Transcriptional control likely requires at least two DNA binding proteins, myocyte enhancer factor-2 and GLUT-4 enhancer factor, which bind to the promoter. Increased GLUT-4 expression may be mediated by the enzyme AMP-activated kinase, which is activated during exercise and has been demonstrated to increase GLUT-4 transcription. Further research needs to be done to investigate whether AMP-activated kinase activates myocyte enhancer factor-2 and GLUT-4 enhancer factor to increase transcription of the GLUT-4 gene.
Department of Biochemistry, Brody School of Medicine, East Carolina University, Greenville, North Carolina 27858, USA. dohmg@mail.ecu.edu
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D000818:Animals; D015444:Exercise / Q000502:physiology*; D051275:Glucose Transporter Type 4; D006801:Humans; D007328:Insulin / Q000502:physiology*; D009004:Monosaccharide Transport Proteins / Q000502:physiology*; D009124:Muscle Proteins; D018482:Muscle, Skeletal / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human