KISS1R (Kisspeptin Receptor): KISS1R, also known as GPR54, is a receptor essential for activating the hypothalamic-pituitary-gonadal axis, which is key to the onset of puberty and fertility. It binds to kisspeptin, a neuropeptide that triggers the release of gonadotropin-releasing hormone and regulates reproductive hormone levels. Mutations in KISS1R can cause hypogonadotropic hypogonadism, a condition marked by delayed or absent puberty and impaired reproductive function. The receptor is also involved in metabolic regulation and has been investigated for its potential role in tumor suppression.