Dual role of the beta2-adrenergic receptor C terminus for the binding of beta-arrestin and receptor internalization.
Homologous desensitization of beta2-adrenergic and other G-protein-coupled receptors is a two-step process. After phosphorylation of agonist-occupied receptors by G-protein-coupled receptor kinases, they bind beta-arrestins, which triggers desensitization and internalization of the receptors. Because it is not known which regions of the receptor are recognized by beta-arrestins, we have investigated beta-arrestin interaction and internalization of a set of mutants of the human beta2-adrenergic receptor. Mutation of the four serine/threonine residues between residues 355 and 364 led to the loss of agonist-induced receptor-beta-arrestin2 interaction as revealed by fluorescence resonance energy transfer (FRET), translocation of beta-arrestin2 to the plasma membrane, and receptor internalization. Mutation of all seven serine/threonine residues distal to residue 381 did not affect agonist-induced receptor internalization and beta-arrestin2 translocation. A beta2-adrenergic receptor truncated distal to residue 381 interacted normally with beta-arrestin2, whereas its ability to internalize in an agonist-dependent manner was compromised. A similar impairment of internalization was observed when only the last eight residues of the C terminus were deleted. Our experiments show that the C terminus distal to residue 381 does not affect the initial interaction between receptor and beta-arrestin, but its last eight amino acids facilitate receptor internalization in concert with beta-arrestin2.
Krasel
Cornelius
C
Institute of Pharmacology and Toxicology, Versbacher Strasse 9, D-97078 Wuerzburg, Germany. c.krasel@reading.ac.uk
Zabel
Ulrike
U
Lorenz
Kristina
K
Reiner
Susanne
S
Al-Sabah
Suleiman
S
Lohse
Martin J
MJ
D000595:Amino Acid Sequence; D019390:Arrestins / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation; D011485:Protein Binding; D021381:Protein Transport; D018343:Receptors, Adrenergic, beta-2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D000071557:beta-Arrestins
D019390:Arrestins; D008024:Ligands; D018343:Receptors, Adrenergic, beta-2; D000071557:beta-Arrestins