What do GLUT4 transporters do?
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).
What are GLUT4 receptors?
GLUT4 is insulin-responsive glucose transporter, found in the skeletal muscle, heart, adipose tissue, and brain. GLUT4 is present in vesicles in cytoplasm of the cells. Binding of insulin to insulin receptor causes translocation of GLUT4 to cell membrane.
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 does GLUT4 do without insulin?
In the absence of insulin, Glut4 slowly recycles between the plasma membrane and vesicular compartments within the cell, where most of the Glut4 resides. Insulin stimulates the translocation of a pool of Glut4 to the plasma membrane, through a process of targeted exocytosis.
What triggers GLUT4?
Bradykinin directly triggers GLUT4 translocation via an insulin-independent pathway. Diabetes.
How does exercise affect GLUT4?
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 type of transporter is GLUT4?
GLUT4 (SLC2A4) is the insulin-responding glucose transporter, found predominantly in muscle cells and adipocytes (fat cells). After a meal, glucose that is absorbed from the digestive system and circulates in the blood now stimulates the release of insulin from the pancreas (Figure 4.10).
How is GLUT4 activated?
The mechanism for GLUT4 is an example of a cascade effect, where binding of a ligand to a membrane receptor amplifies the signal and causes a cellular response. In this case, insulin binds to the insulin receptor in its dimeric form and activates the receptor’s tyrosine-kinase domain.