Phosphoinositide 3-kinase regulates β2-adrenergic receptor endocytosis by AP-2 recruitment to the receptor/β-arrestin complex

SV Naga Prasad, SA Laporte, D Chamberlain… - The Journal of cell …, 2002 - rupress.org
SV Naga Prasad, SA Laporte, D Chamberlain, MG Caron, L Barak, HA Rockman
The Journal of cell biology, 2002rupress.org
Internalization of β-adrenergic receptors (βARs) occurs by the sequential binding of β-
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 βARKinase1
directly interacts with the PIK domain of PI3K to form a cytosolic complex. Overexpression of
the PIK domain displaces endogenous PI3K from βARK1 and prevents βARK1-mediated …
Internalization of β-adrenergic receptors (βARs) occurs by the sequential binding of β-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 βARKinase1 directly interacts with the PIK domain of PI3K to form a cytosolic complex. Overexpression of the PIK domain displaces endogenous PI3K from βARK1 and prevents βARK1-mediated translocation of PI3K to activated β2ARs. Furthermore, disruption of the βARK1/PI3K interaction inhibits agonist-stimulated AP-2 adaptor protein recruitment to the β2AR 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 βARs, and support a role for the localized generation of D-3 phosphoinositides in regulating the recruitment of the receptor/cargo to clathrin-coated pits.
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