Phosphorylation of beta-arrestin2 regulates its function in internalization of beta(2)-adrenergic receptors.
Beta-arrestins mediate agonist-dependent desensitization and internalization of G protein-coupled receptors. Previously, we have shown that phosphorylation of beta-arrestin1 by ERKs at Ser-412 regulates its association with clathrin and its function in promoting clathrin-mediated internalization of the receptor. In this paper we report that beta-arrestin2 is also phosphorylated, predominantly at residues Thr-383 and Ser-361. Isoproterenol stimulation of the beta(2)-adrenergic receptor promotes dephosphorylation of beta-arrestin2. Mutation of beta-arrestin2 phosphorylation sites to aspartic acid decreases the association of beta-arrestin2 with clathrin, thereby reducing its ability to promote internalization of the beta(2)-adrenergic receptor. Its ability to bind and desensitize the beta(2)-adrenergic receptor is, however, unaltered. These results suggest that, analogous to beta-arrestin1, phosphorylation/dephosphorylation of beta-arrestin2 regulates clathrin-mediated internalization of the beta(2)-adrenergic receptor. In contrast to beta-arrestin1, which is phosphorylated by ERK1 and ERK2, phosphorylation of beta-arrestin2 at Thr-383 is shown to be mediated by casein kinase II. Recently, it has been reported that phosphorylation of visual arrestin at Ser-366 prevents its binding to clathrin. Thus it appears that the function of all arrestin family members in mediating internalization of G protein-coupled receptors is regulated by distinct phosphorylation/dephosphorylation mechanisms.
Howard Hughes Medical Institute and Departments of Medicine and Biochemistry, Duke University Medical Center, Box 3821, Durham, NC 27710, USA.
Fang-Tsyr
FT
Lin
Wei
W
Chen
Sudha
S
Shenoy
Mei
M
Cong
Sabrina T
ST
Exum
Robert J
RJ
Lefkowitz
D058666:Adrenergic beta-2 Receptor Agonists; D000818:Animals; D019390:Arrestins / Q000235:genetics / Q000378:metabolism*; D019556:COS Cells; D047390:Casein Kinase II; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism; D015536:Down-Regulation; D004705:Endocytosis; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017354:Point Mutation / Q000235:genetics; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D012694:Serine / Q000235:genetics / Q000378:metabolism; D013912:Threonine / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D000071557:beta-Arrestins
D058666:Adrenergic beta-2 Receptor Agonists; D019390:Arrestins; D002966:Clathrin; D018343:Receptors, Adrenergic, beta-2; D000071557:beta-Arrestins; D013912:Threonine; D012694:Serine; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D007545:Isoproterenol