δ and μ opioid receptors are homologous G protein-coupled receptors that are differentially
sorted between divergent degradative and recycling membrane pathways following agonist-
induced endocytosis. Whereas δ opioid receptors are selectively sorted to lysosomes, μ
opioid receptors recycle rapidly to the plasma membrane by a process that has been
proposed to occur via bulk membrane flow. We have observed that μ opioid receptors do not
recycle by default and have defined a specific sequence present in the cytoplasmic tail of the …