Glucose transporter type 4 (GLUT4) (GLUT4)

Glucose transporter type 4 (GLUT4) is an insulin-responsive facilitative glucose transporter primarily expressed in skeletal muscle, adipose tissue, and cardiomyocytes, where it mediates the majority of insulin-stimulated glucose uptake via ATP-independent facilitated diffusion across the plasma membrane. In the basal state, GLUT4 resides in intracellular storage vesicles, translocating to the cell surface upon insulin or exercise stimulation through pathways involving PI3K, AMPK, and other signaling cascades, thereby increasing glucose influx for metabolism, glycogen storage, or lipid synthesis. This process is critical for maintaining whole-body glucose homeostasis, with approximately 80% of postprandial glucose disposal occurring via GLUT4 in muscle. Dysregulation of GLUT4 translocation or expression contributes to insulin resistance in type 2 diabetes and obesity, where defective signaling impairs glucose uptake despite hyperglycemia. Drugs like metformin and thiazolidinediones target upstream pathways to enhance GLUT4 trafficking and expression, improving glycemic control, though challenges include variable efficacy in advanced disease states.

Other names

insulin-responsive glucose transporterinsulin-regulated glucose transporterinsulin-regulated facilitative glucose transporter

Improves GLUT4 translocation to plasma membrane, enhances insulin-stimulated glucose uptake, activates AMPK or PPAR pathways to upregulate GLUT4 expression