What is the difference between GLUT1 and GLUT4?

GLUT1 is expressed in most cells, is localized primarily at the cell membrane, and is thought to participate mainly in basal glucose transport in muscle. GLUT4 is expressed only by cells that accelerate glucose transport in response to insulin (skeletal muscle, heart muscle, and adipose cells).

What is the difference between GLUT4 and GLUT2?

The high Km of GLUT2 allows for glucose sensing; rate of glucose entry is proportional to blood glucose levels. GLUT4 transporters are insulin sensitive, and are found in muscle and adipose tissue. The drug metformin phosphorylates GLUT4, thereby increasing its sensitivity to insulin.

What is the difference between GLUT1 and GLUT2?

GLUT1 (SLC2A1) was the first to be cloned, and this gene is highly expressed in red blood cells and the blood–brain barrier. GLUT2 (SLC2A2) is expressed in the intestine and kidney where it plays an important role in facilitated glucose transport across the basolateral membrane.

What is the general structure of the GLUTs?

GLUTs are integral membrane proteins that contain 12 membrane-spanning helices with both the amino and carboxyl termini exposed on the cytoplasmic side of the plasma membrane.

Is GLUT4 facilitated diffusion?

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?

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.

Does GLUT1 have quaternary structure?

GLUT1 contains only one subunit, so it does not have quaternary structure. The only ligand associated with GLUT1 is the B-nonylglucoside sugar. B-NG binds to the ligand-binding site on the outward-open GLUT1, which increases interactions between the N and C domains on the extracellular side of the membrane.

Where is GLUT1 found?

The GLUT1 protein is embedded in the outer membrane surrounding cells , where it transports a simple sugar called glucose into cells from the blood or from other cells for use as fuel. In the brain, the GLUT1 protein is involved in moving glucose, which is the brain’s main energy source, across the blood-brain barrier.

What type of transport is GLUT4?

insulin-regulated glucose transporter
GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle (skeletal and cardiac). The first evidence for this distinct glucose transport protein was provided by David James in 1988.

Does brain use GLUT4?

First, GLUT4 is preferentially and highly expressed in brain areas associated with the control of motor activity such as the cortex and the cerebellum. In these areas, translocation of GLUT4 may provide additional glucose to motor neurons under conditions of high energy demand such as a high rate of neuronal firing.