Melanotropin receptor

Melanotropin receptor (also known as melanocortin receptor) is a type of G protein-coupled receptor that is expressed in various tissues and cells in the body. It is involved in a wide range of physiological processes, including skin pigmentation, energy homeostasis, and immune response.

Structure

The melanotropin receptor is a member of the rhodopsin-like family of G protein-coupled receptors. It is composed of seven transmembrane helices, an extracellular N-terminus, and an intracellular C-terminus. The receptor is activated by the binding of a melanocortin peptide to its extracellular domain.

Function

The primary function of the melanotropin receptor is to mediate the effects of melanocortin peptides. These peptides are produced by the pituitary gland and are involved in a variety of physiological processes.

In the skin, the activation of the melanotropin receptor by alpha-melanocyte-stimulating hormone (α-MSH) leads to the production of melanin, a pigment that gives color to the skin, hair, and eyes. This process is crucial for the protection of the skin against ultraviolet (UV) radiation.

In the brain, the melanotropin receptor regulates energy homeostasis by controlling food intake and energy expenditure. It also plays a role in the immune system by modulating the activity of immune cells.

Clinical significance

Mutations in the genes encoding the melanotropin receptor can lead to various disorders. For example, mutations in the MC1R gene, which encodes the melanocortin 1 receptor, are associated with red hair and fair skin in humans, and an increased risk of skin cancer.

Furthermore, the melanotropin receptor is a potential target for the treatment of obesity and related metabolic disorders. Drugs that can activate the melanocortin 4 receptor have been shown to reduce food intake and body weight in animal models.

See also

• Melanocortin
• G protein-coupled receptor
• MC1R
• Alpha-melanocyte-stimulating hormone

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