What is the function of protein GLUT4?

Skeletal muscle both stores glucose as glycogen and oxidizes it to produce energy following the transport step. The principal glucose transporter protein that mediates this uptake is GLUT4, which plays a key role in regulating whole body glucose homeostasis.

What type of receptor 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).

What is GLUT4 expression?

GLUT4 is expressed in adipocytes, where insulin stimulates its translocation from intracellular locations to the cell membrane, which leads to increase of glucose uptake[88]. High expression levels of GLUT4 in adipose tissue can enhance insulin sensitivity and glucose tolerance[89].

What is the role of GLUT4 transporters?

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 does GLUT4 do without insulin?

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 role does GLUT4 protein play in glucose homeostasis?

Skeletal muscle both stores glucose as glycogen and oxidizes it to produce energy following the transport step. The GLUT4 glucose transporter is thus a major mediator of glucose removal from the circulation and a key regulator of whole-body glucose homeostasis.

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.

What is the function of a permease?

A permease (porter) is a protein or protein complex that catalyzes a vectorial reaction, irrespective of whether or not it also catalyzes a chemical or electron transfer reaction that drives the vectorial process.

What is the function of the periplasmic binding protein-dependent permease?

The periplasmic binding protein-dependent permeases constitute a large and important class of active transport systems for the uptake of nutrients by Gram-negative bacteria (Ames, 1986; Furlong, 1987; Higgins, 1992 ).

What is the function of β-D-glucuronide permease?

Other bacterial permeases are the β-D-glucuronide permease of E. coli ( Stoeber, 1957; Kepes and Cohen, 1962) and the α-glucoside permease of the same organism. α-Glucoside permease may be responsible for glucose transport since glucose strongly inhibits the uptake of α-methyl glucoside (Cohen and Monod, 1957 ).