RT Journal Article SR Electronic T1 Subtype-Specific Intracellular Trafficking of α2-Adrenergic Receptors JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 711 OP 720 DO 10.1124/mol.51.5.711 VO 51 IS 5 A1 David A. Daunt A1 Carl Hurt A1 Lutz Hein A1 Jaana Kallio A1 Felix Feng A1 Brian K. Kobilka YR 1997 UL http://molpharm.aspetjournals.org/content/51/5/711.abstract AB The three α2-adrenergic receptor subtypes (α2a, α2b, and α2c) are highly homologous G protein-coupled receptors. These receptors all couple to pertussis toxin-sensitive G proteins and have relatively similar pharmacological properties. To further explore functional differences between these receptors, we used immunocytochemical techniques to compare the ability of the three α2-receptor subtypes to undergo agonist-mediated internalization. The α2a-receptor does not internalize after agonist treatment. In contrast, we observed that the α2b-receptor is able to undergo agonist-induced internalization and seems to follow the same endosomal pathway used by the β2-adrenergic receptor. Attempts to examine internalization of the α2c-receptor were complicated by the fact that the majority of the α2c-receptor resides in the endoplasmic reticulum and cis/medial Golgi and there is relatively little cell surface localization. Nevertheless, we were able to detect some internalization of the α2c-receptor after prolonged agonist treatment. However, we observed no significant movement of α2c-receptor from the intracellular pool to the plasma membrane during a 4-hr treatment of cells with cycloheximide, suggesting that these cells are unable to process α2c-receptors in the same way they process the α2a or α2b subtypes.