Which glut transporters are insulin responsive?

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 kind of transport is carried out by GLUT1?

3.8 GLUT1: Facilitated Transport of Glucose. GLUT1 is a transmembrane protein responsible for the facilitated diffusion of glucose across a membrane. This is an example of a membrane protein facilitating passive transport in which net flux can only occur down a concentration gradient of glucose.

What is the function of GLUT1?

The glucose transporter GLUT1, a plasma membrane protein that mediates glucose homeostasis in mammalian cells, is responsible for constitutive uptake of glucose into many tissues and organs. Many studies have focused on its vital physiological functions and close relationship with diseases.

Does insulin affect GLUT2?

RESULTS AND CONCLUSIONS—In Caco-2/TC7 cells, insulin action diminished the transepithelial transfer of sugar and reduced BBM and basolateral membrane (BLM) GLUT2 levels, demonstrating that insulin can target sugar absorption by controlling the membrane localization of GLUT2 in enterocytes.

Does GLUT4 require insulin?

GLUT4 in a nutshell In the absence of insulin, the majority of GLUT4 is stored in small intracellular vesicles [referred to as GLUT4 storage vesicles (GSVs) (Martin et al., 1998) or insulin responsive vesicles (IRVs) (Kupriyanova et al., 2002)].

How is insulin broken down in the body?

Once in the cells, the glucose is used as the energy to fuel the cells doing their different jobs or is stored in the liver or muscle cells as glycogen. This results in the glucose level of the blood dropping, which then triggers the pancreas to switch off the release of insulin.

Is GLUT1 active or passive transport?

There are two types of glucose transporters in the brain: the glucose transporter proteins (GLUTs) that transport glucose through facilitative diffusion (a form of passive transport), and sodium-dependent glucose transporters (SGLTs) that use an energy-coupled mechanism (active transport).

Is GLUT1 insulin dependent?

GLUT1 is insulin-independent and is widely distributed in different tissues. GLUT4 is insulin-dependent and is responsible for the majority of glucose transport into muscle and adipose cells in anabolic conditions.

Does glut 1 require insulin?

Does GLUT2 need insulin?

In pancreatic beta cells, GLUT2 is required for glucose-stimulated insulin secretion. In hepatocytes, suppression of GLUT2 expression revealed the existence of an unsuspected glucose output pathway that may depend on a membrane traffic-dependent mechanism.

Is insulin a carrier protein?

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….GLUT4.

What does insulin do to your blood sugar?

The pancreas responds by producing insulin, which allows glucose to enter the body’s cells to provide energy. Store excess glucose for energy. After you eat — when insulin levels are high — excess glucose is stored in the liver in the form of glycogen.

How does GLUT4 affect insulin-independent glucose transport?

Hexosamines have a negative feedback effect on GLUT4, and reduced GLUT4 activity decreases insulin-mediated glucose uptake. Thus, insulin-independent glucose transport through GLUT1 can meet the basal needs of the muscle cell.

Which is glucose transport protein is insulin dependent?

The glucose transport proteins (GLUT1 and GLUT4) facilitate glucose transport into insulin-sensitive cells. GLUT1 is insulin-independent and is widely distributed in different tissues. GLUT4 is insulin-dependent and is responsible for the majority of glucose transport into muscle and adipose cells in anabolic conditions.

Which is the most ubiquitous glucose transporter isoform?

GLUT1 is the most ubiquitously distributed of the transporter isoforms. It is found in virtually all tissues of the fetus and in many tissues and cell types of the adult. 39-46 GLUT1 has a very high affinity for glucose. These properties make it likely that GLUT1 is responsible for constitutive glucose uptake.

Is the GLUT1 transporter expressed in the fetus?

GLUT1 is the predominant isoform of the fetus. This transporter is also expressed in fetal tissues that fail to express it significantly in the adult. Most fetal cells exhibit rapid growth and differentiation, necessitating an increased supply of energy-producing substrates.