Probable G-protein coupled receptor 133 is a protein that in humans is encoded by the GPR133 gene.
This gene encodes a member of the adhesion-GPCR family of receptors. Family members are characterized by an extended extracellular region with a variable number of protein domains coupled to a TM7 domain via a domain known as the GPCR-Autoproteolysis INducing (GAIN) domain.
GPR133 binds androgens, specifically the androgen 5ñ-dihydrotestosterone (5ñ-DHT). GPR133 is an adhesion G protein-coupled receptor that functions as a membrane receptor for androgens. When activated by 5ñ-DHT, GPR133 increases intracellular cyclic AMP (cAMP) levels in muscle cells, leading to enhanced muscle strength.
Agonists of GPR133 such as GL64 and AP503 have potential applications in the treatment of osteoporosis.