G Protein-Coupled Receptor Family C 6A (GPRC6A): Possible molecular target in Bone

gprc6a is a recently identified member of family c of g protein-coupled receptors (gpcrs) that is closely related to the calcium-sensing receptor casr. it has recently been shown that gprc6a extracellular cations and amino acids and requires both extracellular cations and amino acids for optimal stimulation in vitro. the study of the ligand profile of gprc6a has shown that l-ornithine is the most potent and efficacious l-amino acid agonist, followed by several other aliphatic, neutral, and basic amino acids. some studies show cation-dependent activation of gprc6a, but compared to casr, much higher extracellular calcium concentrations are needed to activate this receptor. furthermore, the divalent cation mg(2+) was found to be a positive modulator of the l-ornithine response. gprc6a may be a candidate for the elusive extracellular calcium-sensing mechanism known to be present in osteoblasts, which respond to high local ca2+ concentrations. gprc6a has also been proposed as a candidate receptor for ostocalcin, regulating energy metabolism and as a molecular target for the action of strontium on bone.