Molecular mechanism of Cannabinoid receptor 1 regulation by SGIP1

Molecular mechanism of Cannabinoid receptor 1 regulation by SGIP1 Abstract Src homology 3-domain growth factor receptor-bound 2-like endophilin interacting protein 1 (SGIP1) has been identified as an interacting partner of cannabinoid receptor 1 (CB1R). Their protein-protein interaction was confirmed by co-immunoprecipitation. SGIP1 hinders the internalization of activated CB1R and modulates its signaling in HEK293 cells. Employing whole-cell patch-clamp electrophysiology, we have shown that SGIP1 affects CB1R signaling in autaptic hippocampal neurons. Using a battery of behavioral tests in SGIP1 constitutive knock-out (SGIP1-/- ) and WT mice, we investigated the consequences of SGIP1 deletion on behavior regulated by the endocannabinoid system. In SGIP1-/- mice, exploratory levels, working memory and sensorimotor gating were unaltered. SGIP1-/- mice showed decreased anxiety-like and depressive-like behaviors. Fear extinction to tone was enhanced in SGIP1-/- females. Several cannabinoid tetrad behaviors were altered in the absence of SGIP1. SGIP1-/- males exhibited abnormal THC withdrawal behaviors. SGIP1 deletion also reduced acute nociception, and SGIP1-/- mice were more sensitive to antinociceptive effects of CB1R agonists and morphine. CB1R-SGIP1 interaction results in profound modification of CB1R..