This research paper identifies GPR55 as a novel cannabinoid receptor. The study demonstrates that GPR55 binds and is activated by various cannabinoid ligands, including CP55940, anandamide, and virodhamine. GPR55 couples to Gα13 and can mediate activation of small G proteins such as rhoA, cdc42, and rac1. The findings suggest that GPR55 is a novel cannabinoid receptor, distinct from the well-characterized CB1 and CB2 receptors. The study also shows that ligands such as cannabidiol and abnormal cannabidiol, which do not activate CB1 or CB2 receptors, exhibit activity at GPR55. These results indicate that GPR55 may play a role in various physiological processes, including those involving the endocannabinoid system. The study provides evidence that GPR55 is a potential candidate for a non-CB1/CB2 cannabinoid receptor, highlighting its importance in understanding the broader cannabinoid receptor family.This research paper identifies GPR55 as a novel cannabinoid receptor. The study demonstrates that GPR55 binds and is activated by various cannabinoid ligands, including CP55940, anandamide, and virodhamine. GPR55 couples to Gα13 and can mediate activation of small G proteins such as rhoA, cdc42, and rac1. The findings suggest that GPR55 is a novel cannabinoid receptor, distinct from the well-characterized CB1 and CB2 receptors. The study also shows that ligands such as cannabidiol and abnormal cannabidiol, which do not activate CB1 or CB2 receptors, exhibit activity at GPR55. These results indicate that GPR55 may play a role in various physiological processes, including those involving the endocannabinoid system. The study provides evidence that GPR55 is a potential candidate for a non-CB1/CB2 cannabinoid receptor, highlighting its importance in understanding the broader cannabinoid receptor family.