GLUTfehérjék

GLUT feherjek, also known as glucose transporter proteins, are a family of integral membrane proteins responsible for facilitating the transport of glucose across cell membranes. These proteins are crucial for cellular metabolism, as glucose is a primary energy source for most cells. There are several different GLUT isoforms, each with distinct tissue distribution, kinetic properties, and regulatory mechanisms.

The GLUT family is divided into three classes. Class I GLUTs, including GLUT1, GLUT2, GLUT3, and GLUT4, are structurally similar and facilitate glucose transport via facilitated diffusion. GLUT1 is ubiquitously expressed and responsible for basal glucose uptake. GLUT2 is primarily found in the liver, pancreas, and intestine, and has a high capacity for glucose transport. GLUT3 is the primary glucose transporter in neurons, ensuring a constant supply of glucose to the brain. GLUT4 is insulin-responsive and found in adipose tissue and skeletal muscle, playing a key role in glucose homeostasis after meals.

Class II GLUTs (GLUT5, GLUT7, GLUT9, GLUT11) are structurally different and primarily transport hexoses other than glucose, such as fructose. Class III GLUTs (GLUT6, GLUT8, GLUT10, GLUT12) are also structurally distinct and have diverse roles, with some being proton-coupled hexose transporters.

The activity of GLUT proteins, particularly GLUT4, is tightly regulated by hormones like insulin, which promotes their translocation to the cell surface, thereby increasing glucose uptake. Dysregulation of GLUT protein function is implicated in various metabolic disorders, including diabetes mellitus. Research into GLUT proteins continues to be vital for understanding energy metabolism and developing therapeutic strategies for related diseases.