Glucagon-like peptide receptor

Glucagon-like peptide receptor (GLP-1R) is a G protein-coupled receptor (GPCR) that binds glucagon-like peptide-1 (GLP-1), a hormone involved in the regulation of blood glucose levels. The receptor is expressed in various tissues, including the pancreas, brain, and heart, and plays a crucial role in glucose homeostasis and satiety.

Structure

The GLP-1R is a member of the class B GPCR family, which also includes receptors for glucagon, parathyroid hormone, and calcitonin. Like other GPCRs, it has seven transmembrane domains, an extracellular N-terminus, and an intracellular C-terminus. The N-terminus is responsible for ligand binding, while the C-terminus is involved in receptor activation and internalization.

Function

Upon binding of GLP-1, the GLP-1R activates the G protein, which in turn stimulates adenylate cyclase to increase the production of cyclic AMP (cAMP). This leads to the activation of protein kinase A (PKA) and the subsequent phosphorylation of various proteins, resulting in the regulation of glucose homeostasis and satiety.

In the pancreas, activation of the GLP-1R stimulates insulin secretion in a glucose-dependent manner, thereby lowering blood glucose levels. In the brain, it promotes satiety and reduces food intake. In the heart, it has been shown to improve cardiac function and survival in animal models of heart failure.

Clinical significance

Mutations in the GLP-1R gene have been associated with type 2 diabetes and obesity. Furthermore, GLP-1R agonists, such as exenatide and liraglutide, are used in the treatment of type 2 diabetes. These drugs mimic the action of GLP-1 and stimulate insulin secretion, thereby improving blood glucose control.

See also

• Glucagon-like peptide-1
• G protein-coupled receptor
• Type 2 diabetes
• Obesity

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