Human Parathyroid Hormone Receptor 1 (PTH1R) Protein

Background

PTH1R is a G protein-coupled receptor activated by parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrP). It is primarily expressed in bone, kidney, and cartilage, where it regulates calcium and phosphate homeostasis, bone remodeling, and cartilage development. PTH1R couples to both Gs and Gq proteins, leading to activation of adenylate cyclase (increasing cAMP) and phospholipase C (PLC) pathways. In bone, PTH1R mediates osteoblast activation, enhancing bone formation and resorption in response to PTH. In the kidney, PTH1R regulates calcium reabsorption and phosphate excretion to maintain calcium balance. Dysregulation of PTH1R signaling is associated with hyperparathyroidism, hypoparathyroidism, and bone diseases like osteoporosis. PTH analogs that target PTH1R are used therapeutically to treat osteoporosis and hypoparathyroidism by promoting bone growth and mineral homeostasis. PTH1R’s essential role in calcium regulation and skeletal health makes it a key target for metabolic bone diseases.