title: Phosphoinositide 3-kinase regulates beta2-adrenergic receptor endocytosis by AP-2 recruitment to the receptor/beta-arrestin complex.
abstract: Internalization of beta-adrenergic receptors (betaARs) occurs by the sequential binding of beta-arrestin, the clathrin adaptor AP-2, and clathrin. D-3 phosphoinositides, generated by the action of phosphoinositide 3-kinase (PI3K) may regulate the endocytic process; however, the precise molecular mechanism is unknown. Here we demonstrate that betaARKinase1 directly interacts with the PIK domain of PI3K to form a cytosolic complex. Overexpression of the PIK domain displaces endogenous PI3K from betaARK1 and prevents betaARK1-mediated translocation of PI3K to activated beta2ARs. Furthermore, disruption of the betaARK1/PI3K interaction inhibits agonist-stimulated AP-2 adaptor protein recruitment to the beta2AR and receptor endocytosis without affecting the internalization of other clathrin dependent processes such as internalization of the transferrin receptor. In contrast, AP-2 recruitment is enhanced in the presence of D-3 phospholipids, and receptor internalization is blocked in presence of the specific phosphatidylinositol-3,4,5-trisphosphate lipid phosphatase PTEN. These findings provide a molecular mechanism for the agonist-dependent recruitment of PI3K to betaARs, and support a role for the localized generation of D-3 phosphoinositides in regulating the recruitment of the receptor/cargo to clathrin-coated pits.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Sathyamangla V
authors.initials: SV
authors.lastname: Naga Prasad
authors.forename: Stéphane A
authors.initials: SA
authors.lastname: Laporte
authors.forename: Dean
authors.initials: D
authors.lastname: Chamberlain
authors.forename: Marc G
authors.initials: MG
authors.lastname: Caron
authors.forename: Larry
authors.initials: L
authors.lastname: Barak
authors.forename: Howard A
authors.initials: HA
authors.lastname: Rockman
mesh_terms: D033981:Adaptor Protein Complex delta Subunits; D033942:Adaptor Proteins, Vesicular Transport; D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D019390:Arrestins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology* / Q000648:ultrastructure; D002478:Cells, Cultured; D002966:Clathrin / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis / Q000502:physiology*; D005057:Eukaryotic Cells / Q000201:enzymology* / Q000648:ultrastructure; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D051059:PTEN Phosphohydrolase; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport / Q000502:physiology; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D014168:Transferrin / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D051552:beta-Adrenergic Receptor Kinases; D000071557:beta-Arrestins
chemical_list: D033981:Adaptor Protein Complex delta Subunits; D033942:Adaptor Proteins, Vesicular Transport; D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists; D019390:Arrestins; D002352:Carrier Proteins; D002966:Clathrin; D008565:Membrane Proteins; D018129:Phosphatidylinositol Phosphates; D018343:Receptors, Adrenergic, beta-2; D014168:Transferrin; D025521:Tumor Suppressor Proteins; D000071557:beta-Arrestins; C060974:phosphatidylinositol 3,4,5-triphosphate; D019869:Phosphatidylinositol 3-Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D051552:beta-Adrenergic Receptor Kinases; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D007545:Isoproterenol