Calcium-Sensing Receptor (CaSR) is a member of the G protein-coupled receptor family. CaSR is an integral membrane protein that senses changes in the extracellular concentration of calcium ions and controls the release of parathyroid hormone. The activity of the calcium-sensing receptor is mediated by a G-protein that activates a phosphatidylinositol-calcium second messenger system.
Mutations that inactivate CaSR lead to familial hypocalciuric hypercalcemia, whereas mutations that activate CaSR cause autosomal dominant hypocalcemia. Calcium-Sensing Receptor antibodies are useful tools for parathyroid studies and research on cellular calcium homeostasis regulation.