“…Thus, CB 1 R physically interacts with CB 2 R (25), serotonin (26), adenosine (22,27), opioid (28), orexin (29), and angiotensin (30) receptors, and with the cannabinoid-related orphan receptor GPR55 (31). CB 2 R, on the other hand, has been shown to form heteromers with GPR55 (32, 33) and CXCR4 (34,35). Although several RTK-RTK heteromers and GPCR-GPCR heteromers have been previously described, there are very few examples of physical interaction between RTKs and GPCRs yet.…”