GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac). At the cell surface, GLUT4 permits the facilitated diffusion of circulating glucose down its concentration gradient into muscle and fat cells.
What is the function of GLUT4 receptors?
GLUT4 is an insulin-regulated glucose transporter that is responsible for insulin-regulated glucose uptake into fat and muscle cells. In the absence of insulin, GLUT4 is mainly found in intracellular vesicles referred to as GLUT4 storage vesicles (GSVs).
How is GLUT4 regulated by insulin?
Insulin stimulates glucose transport by promoting translocation of the insulin-sensitive glucose transporter isoform 4 (GLUT4) from an intracellular compartment to the cell surface. This movement is accomplished by stimulation of GLUT4 exocytosis as well as inhibition of endocytosis.
How do you increase GLUT4 receptors?
Exercise training is the most potent stimulus to increase skeletal muscle GLUT4 expression, an effect that may partly contribute to improved insulin action and glucose disposal and enhanced muscle glycogen storage following exercise training in health and disease.
What is GLUT4 expression?
Skeletal muscle is a major glucose-utilizing tissue in the absorptive state and the major glucose transporter expressed in muscle in adulthood is GLUT4. GLUT4 expression is exquisitely regulated in muscle and this seems important in the regulation of insulin-stimulated glucose uptake by this tissues.
How is GLUT4 similar to GLUT 1 How are they different?
While both Glut1 and Glut4 transport glucose with high affinity, their properties of transport differ. Glucose transport under equilibrium exchange conditions show a K(m) for Glut4 which is 3- to 12-fold lower than that of Glut138-40 but under zero-trans conditions, Glut4 has a higher K(m) than Glut1.
Why is GLUT4 important?
GLUT4 is one of the most important downstream sites of the insulin receptor because it sits at the rate-limiting step in the insulin transduction signal pathway. It has been reported that GLUT4 protein and mRNA are reduced in type 2 diabetes (Chen et al., 2003).
What is the role of GLUT4 in response to insulin?
GLUT4 functions for the insulin-dependent translocation of glucose. Thus, insulin stimulates the uptake of glucose by GLUT4 in the muscle cell where hexokinase converts it to glucose-6-phosphate so that the cell may utilize it for either glycolysis for energy or for the formation of glycogen when glucose is abundant.
How does GLUT4 Work?
How does exercise increase GLUT4?
The increase in muscle glucose transport during exercise is primarily due to translocation of GLUT4 from intracellular sites to the sarcolemma and T-tubules, although it is possible that changes in intrinsic activity may also occur.
¿Qué es un transportador de glucosa?
Este transportador de glucosa es expresado principalmente en tejidos periféricos con mayores concentraciones en la grasa parda, corazón, músculo rojo, músculo blanco y grasa blanca, aunque también ha sido encontrado en la pituitaria y el hipotálamo.
¿Qué es el transportador de glucosa en sangre y placenta?
GLUT-3: es el transportador de más alta afinidad por la glucosa. Éste junto con el GLUT-1 en tejido nervioso refuerza la importancia que tiene para mantener el nivel basal de glucosa en sangre y placenta.
¿Cómo ocurre el transporte de glucosa al interior de las células?
El transporte de glucosa al interior de las células ocurre por medio de un proceso de difusión facilitada que es mediado por una familia de transportadores de glucosa (GLUT), que presentan 12 dominios transmembranales.
¿Por qué la insulina estimula el transporte de la glucosa?
Actualmente se sabe que la insulina estimula la incorporación del GLUT 4 a la membrana plasmática a partir de vesículas intracelulares, incrementando de 10 a 20 veces el transporte de la glucosa.
