Rab1 interacts directly with the β2-adrenergic receptor to regulate receptor anterograde trafficking

Very little is understood about the trafficking of G protein-coupled receptors (GPCRs) from the endoplasmic reticulum (ER) to the plasma membrane. Rab guanosine triphosphatases (GTPases) are known to participate in the trafficking of various GPCRs via a direct interaction during the endocytic pathway, but whether this occurs in the anterograde pathway is unknown. We evaluated the potential interaction of Rab1, a GTPase known to regulate β2-adrenergic receptor (β2AR) trafficking, and its effect on export from the ER. Our results show that GTP-bound Rab1 interacts with the F(x) ₆LL motif of β2AR. Receptors lacking the interaction motif fail to traffic properly, suggesting that a direct interaction with Rab1 is required for β2AR anterograde trafficking.