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Dynamin and β-Arrestin Reveal Distinct Mechanisms for G Protein-coupled Receptor Internalization

1996; Elsevier BV; Volume: 271; Issue: 31 Linguagem: Inglês

10.1074/jbc.271.31.18302

1083-351X

Jie Zhang, Stephen S. G. Ferguson, Larry S. Barak, Luc Ménard, Marc G. Caron,

Neuropeptides and Animal Physiology

The process of agonist-promoted internalization (sequestration) of G protein-coupled receptors (GPCRs) is intimately linked to the regulation of GPCR responsiveness. Following agonist-mediated desensitization, sequestration of GPCR is presumably associated with the dephosphorylation and recycling of functional receptors. However, the exact mechanisms responsible for GPCR sequestration, even for the prototypic β2-adrenergic receptor (β2AR), have remained controversial. We demonstrate here that dynamin, a GTPase that regulates the formation and internalization of clathrin-coated vesicles, is essential for the agonist-promoted sequestration of the β2AR, suggesting that the β2AR internalizes via the clathrin-coated vesicle-mediated endocytic pathway. In contrast, internalization of the angiotensin II type 1A receptor (AT1AR), another typical GPCR, does not require dynamin. In addition, the AT1AR internalizes independent of the function of β-arrestin, a critical component for β2AR cellular trafficking, but additional AT1ARs are mobilized to the dynamin-dependent pathway upon overexpression of β-arrestin. These findings demonstrate that GPCRs can utilize distinct endocytic pathways, distinguishable by dynamin and β-arrestin, and that β-arrestins function as adaptor proteins specifically targeting GPCRs for dynamin-dependent endocytosis via clathrin-coated vesicles. The process of agonist-promoted internalization (sequestration) of G protein-coupled receptors (GPCRs) is intimately linked to the regulation of GPCR responsiveness. Following agonist-mediated desensitization, sequestration of GPCR is presumably associated with the dephosphorylation and recycling of functional receptors. However, the exact mechanisms responsible for GPCR sequestration, even for the prototypic β2-adrenergic receptor (β2AR), have remained controversial. We demonstrate here that dynamin, a GTPase that regulates the formation and internalization of clathrin-coated vesicles, is essential for the agonist-promoted sequestration of the β2AR, suggesting that the β2AR internalizes via the clathrin-coated vesicle-mediated endocytic pathway. In contrast, internalization of the angiotensin II type 1A receptor (AT1AR), another typical GPCR, does not require dynamin. In addition, the AT1AR internalizes independent of the function of β-arrestin, a critical component for β2AR cellular trafficking, but additional AT1ARs are mobilized to the dynamin-dependent pathway upon overexpression of β-arrestin. These findings demonstrate that GPCRs can utilize distinct endocytic pathways, distinguishable by dynamin and β-arrestin, and that β-arrestins function as adaptor proteins specifically targeting GPCRs for dynamin-dependent endocytosis via clathrin-coated vesicles.