G protein-coupled receptor 55 (GPR55)

GPR55 is an atypical cannabinoid-responsive GPCR widely expressed in neural tissue but also present peripherally. Its unique ligand profile—responding both to lipids like LPI and some cannabinoids—alongside distinct signaling mechanisms involving calcium mobilization sets it apart from classical cannabinoid receptors CB1/CB2. Ongoing research continues to clarify its physiological functions and therapeutic potential across neurological disorders, oncology, metabolism/bone health.

Agonist binding leads to activation of G proteins (primarily G13/G12), activation of Rho family GTPases (RhoA, cdc42, rac1), intracellular calcium release, and cytoskeletal rearrangement.