Glucose transporter type 4 (GLUT4)

GLUT4 is a facilitative glucose transporter protein encoded by the SLC2A4 gene, primarily found in adipose tissue and striated muscle. It belongs to the Class 1 glucose transporters and the major facilitator superfamily, featuring a 12-transmembrane domain structure. GLUT4 plays a critical role in glucose metabolism by mediating insulin-stimulated glucose uptake into muscle and fat cells via ATP-independent facilitative diffusion. Uniquely, GLUT4 is predominantly stored in intracellular vesicles in the absence of insulin or exercise. Upon insulin stimulation or during exercise, these vesicles translocate to the plasma membrane, increasing glucose transport into the cell. This process involves a complex signaling cascade initiated by insulin binding to its receptor, activating PI3K and AKT, which triggers vesicle fusion. After stimulation, GLUT4 is endocytosed. Dysregulation of GLUT4 expression and function, including mutations or overexpression, is linked to metabolic disorders such as increased fat storage, glucose homeostasis issues, and insulin resistance, making it an important target for understanding and potentially treating these conditions.

Other names

SLC2A4