Glycoprotein hormones, alpha polypeptide

Glycoprotein hormones, alpha polypeptide (also known as CGA) is a protein that in humans is encoded by the CGA gene. This protein is a subunit of the hormones chorionic gonadotropin, luteinizing hormone, follicle-stimulating hormone, and thyroid-stimulating hormone, all of which are glycoprotein hormones.

Structure

The CGA gene is located on the chromosome 6 (6q14.3) and spans approximately 11 kb. The gene includes four exons and three introns. The protein encoded by this gene is a 92-amino acid polypeptide. It is a glycoprotein, meaning it has carbohydrate side chains covalently attached to the polypeptide chain.

Function

The alpha subunit of these hormones is identical, while the beta subunit is unique to each hormone. The alpha subunit is necessary for the biological activity of the hormones and confers the specificity of these hormones. The hormones are secreted by the pituitary gland and have various functions in the body, including regulating metabolism, growth and development, and reproductive processes.

Clinical significance

Mutations in the CGA gene can lead to hypogonadotropic hypogonadism, a condition characterized by low levels of gonadotropins and consequent failure of sexual maturation. Additionally, elevated levels of the alpha subunit can be indicative of tumors in the pituitary gland.

See also

• Glycoprotein hormones, beta polypeptide
• Gonadotropin