Agonist-dependent recruitment of phosphoinositide 3-kinase to the membrane by beta-adrenergic receptor kinase 1. A role in receptor sequestration.
Agonist-dependent desensitization of the beta-adrenergic receptor requires translocation and activation of the beta-adrenergic receptor kinase1 by liberated Gbetagamma subunits. Subsequent internalization of agonist-occupied receptors occurs as a result of the binding of beta-arrestin to the phosphorylated receptor followed by interaction with the AP2 adaptor and clathrin proteins. Receptor internalization is known to require D-3 phosphoinositides that are generated by the action of phosphoinositide 3-kinase. Phosphoinositide 3-kinases form a family of lipid kinases that couple signals via receptor tyrosine kinases and G-protein-coupled receptors. The molecular mechanism by which phosphoinositide 3-kinase acts to promote beta-adrenergic receptor internalization is not well understood. In the present investigation we demonstrate a novel finding that beta-adrenergic receptor kinase 1 and phosphoinositide 3-kinase form a cytosolic complex, which leads to beta-adrenergic receptor kinase 1-mediated translocation of phosphoinositide 3-kinase to the membrane in an agonist-dependent manner. Furthermore, agonist-induced translocation of phosphoinositide 3-kinase results in rapid interaction with the receptor, which is of functional importance, since inhibition of phosphoinositide 3-kinase activity attenuates beta-adrenergic receptor sequestration. Therefore, agonist-dependent recruitment of phosphoinositide 3-kinase to the membrane is an important step in the process of receptor sequestration and links phosphoinositide 3-kinase to G-protein-coupled receptor activation and sequestration.
Naga Prasad
S V
SV
Departments of Medicine and Cell Biology and Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
Barak
L S
LS
Rapacciuolo
A
A
Caron
M G
MG
Rockman
H A
HA
D016475:3T3 Cells; D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002966:Clathrin / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004705:Endocytosis; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009206:Myocardium / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D013997:Time Factors; D051552:beta-Adrenergic Receptor Kinases
D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; D018076:DNA, Complementary; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D051552:beta-Adrenergic Receptor Kinases