Melanocortin 3 receptor

Melanocortin 3 receptor (MC3R) is a protein that in humans is encoded by the MC3R gene. It is one of the five known melanocortin receptors, which are members of the G protein-coupled receptor family. MC3R is primarily expressed in the brain, particularly in the hypothalamus, and has been implicated in the regulation of energy homeostasis and body weight.

Structure

MC3R is a seven-transmembrane domain G protein-coupled receptor that interacts with melanocortin peptides. The receptor is characterized by a large extracellular N-terminal domain and a short intracellular C-terminal tail. The N-terminal domain is thought to play a role in ligand binding, while the C-terminal tail is involved in receptor activation.

Function

MC3R is involved in the regulation of energy homeostasis and body weight. It is activated by melanocortin peptides, including alpha-melanocyte-stimulating hormone (α-MSH) and adrenocorticotropic hormone (ACTH). Activation of MC3R leads to increased cAMP levels and activation of adenylyl cyclase, resulting in increased energy expenditure and decreased food intake.

Clinical significance

Mutations in the MC3R gene have been associated with obesity and insulin resistance. Some studies have suggested that these mutations may increase the risk of type 2 diabetes and cardiovascular disease. However, the exact role of MC3R in these conditions is still not fully understood.

See also

• Melanocortin receptor
• G protein-coupled receptor
• Energy homeostasis
• Body weight
• Obesity
• Insulin resistance
• Type 2 diabetes
• Cardiovascular disease