Glucose transporters (GLUTs) are integral membrane proteins responsible for transporting glucose into the body and cells. This article provides an extensive analysis of the structure of glucose transporters, their substrate specificity, and their clinical significance. GLUTs comprise various isoforms ranging from GLUT1 to GLUT14, each functioning in specific tissues and under distinct physiological conditions. Structurally, they mediate passive glucose transport through transmembrane domains, enabling glucose entry into the cell without energy expenditure. GLUT1 is widely present in many tissues and primarily ensures basal glucose transport. GLUT2 functions as a high-capacity glucose transporter in the liver, kidneys, and enterocytes, while GLUT4 is activated by insulin and plays a crucial role in transporting glucose into skeletal muscle and adipose tissue. The substrate specificity of GLUTs depends on their ability to transport different glucose isoforms, fructose, and other monosaccharides. For example, GLUT5 shows high specificity for fructose, whereas GLUT1 and GLUT3 exhibit high affinity mainly for glucose. These molecular features of glucose transporters are essential for maintaining cellular energy balance and regulating metabolic processes. From a clinical standpoint, dysfunction or altered expression of GLUTs is associated with several diseases. For instance, GLUT1 deficiency leads to developmental abnormalities in the central nervous system, while GLUT4 dysfunction contributes to insulin resistance and the development of diabetes. Additionally, GLUT expression in liver and cancer cells adapts according to metabolic demand, offering opportunities for developing new diagnostic and therapeutic strategies in oncology. This article presents a comprehensive analysis of the molecular structure of GLUTs, their substrate affinity, and their clinical importance under physiological and pathological conditions.

GLUT, glucose, transporter, substrate, structure, insulin, metabolism, diabetes, cell, clinical

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