title: MARCH2 promotes endocytosis and lysosomal sorting of carvedilol-bound β(2)-adrenergic receptors.
abstract: Lysosomal degradation of ubiquitinated β(2)-adrenergic receptors (β(2)ARs) serves as a major mechanism of long-term desensitization in response to prolonged agonist stimulation. Surprisingly, the βAR antagonist carvedilol also induced ubiquitination and lysosomal trafficking of both endogenously expressed β(2)ARs in vascular smooth muscle cells (VSMCs) and overexpressed Flag-β(2)ARs in HEK-293 cells. Carvedilol prevented β(2)AR recycling, blocked recruitment of Nedd4 E3 ligase, and promoted the dissociation of the deubiquitinases USP20 and USP33. Using proteomics approaches (liquid chromatography-tandem mass spectrometry), we identified that the E3 ligase MARCH2 interacted with carvedilol-bound β(2)AR. The association of MARCH2 with internalized β(2)ARs was stabilized by carvedilol and did not involve β-arrestin. Small interfering RNA-mediated down-regulation of MARCH2 ablated carvedilol-induced ubiquitination, endocytosis, and degradation of endogenous β(2)ARs in VSMCs. These findings strongly suggest that specific ligands recruit distinct E3 ligase machineries to activated cell surface receptors and direct their intracellular itinerary. In response to β blocker therapy with carvedilol, MARCH2 E3 ligase activity regulates cell surface β(2)AR expression and, consequently, its signaling.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Sang-oh
authors.initials: SO
authors.lastname: Han
authors.forename: Kunhong
authors.initials: K
authors.lastname: Xiao
authors.forename: Jihee
authors.initials: J
authors.lastname: Kim
authors.forename: Jiao-Hui
authors.initials: JH
authors.lastname: Wu
authors.forename: James W
authors.initials: JW
authors.lastname: Wisler
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nakamura
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Freedman
authors.forename: Sudha K
authors.initials: SK
authors.lastname: Shenoy
mesh_terms: D000818:Animals; D002227:Carbazoles / Q000494:pharmacology*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D000077261:Carvedilol; D004705:Endocytosis; D057809:HEK293 Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D011412:Propanolamines / Q000494:pharmacology*; D051381:Rats; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases
chemical_list: D002227:Carbazoles; D002352:Carrier Proteins; D008565:Membrane Proteins; D011412:Propanolamines; D018343:Receptors, Adrenergic, beta-2; D000077261:Carvedilol; C502926:MARCHF2 protein, human; D044767:Ubiquitin-Protein Ligases