| 1. |
- Neuschäfer-Rube, Frank, et al.
(författare)
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Identification of a Ser/Thr cluster in the C-terminal domain of the human prostaglandin EP4-R essential for agonist-induced beta-arrestin1 recruitment that differs from the apparent principal phosphorylation site.
- 2004
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Ingår i: Biochemical Journal. - 0264-6021. ; 379:3, s. 573-585
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Tidskriftsartikel (refereegranskat)abstract
- hEP4-R (human prostaglandin E2 receptor, subtype EP4) is a Gs-linked heterotrimeric GPCR (G-protein-coupled receptor). It undergoes agonist-induced desensitization and internalization that depend on the presence of its C-terminal domain. Desensitization and internalization of GPCRs are often linked to agonist-induced b-arrestin complex formation, which is stabilized by phosphorylation. Subsequently b-arrestin uncouples the receptor from its G-protein and links it to the endocytotic machinery. The C-terminal domain of hEP4-R contains 38 Ser/Thr residues that represent potential phosphorylation sites. The present study aimed to analyse the relevance of these Ser/Thr residues for agonist-induced phosphorylation, interaction with b-arrestin and internalization. In response to agonist treatment, hEP4-R was phosphorylated. By analysis of proteolytic phosphopeptides of the wild-type receptor and mutants in which groups of Ser/Thr residues had been replaced by Ala, the principal phosphorylation site was mapped to a Ser/Thr-containing region comprising residues 370–382, the presence of which was necessary and sufficient to obtain full agonist-induced phosphorylation. A cluster of Ser/Thr residues (Ser-389–Ser-390–Thr-391–Ser-392) distal to this site, but not the principal phosphorylation site, was essential to allow agonist-induced recruitment of b-arrestin1. However, phosphorylation greatly enhanced the stability of the b-arrestin1–receptor complexes. For maximal agonist-induced internalization, phosphorylation of the principal phosphorylation site was not required, but both b-arrestin1 recruitment and the presence of Ser/Thr residues in the distal half of the C-terminal domain were necessary.
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| 2. |
- Neuschäfer-Rube, Frank, et al.
(författare)
-
Identification of a Ser/Thr cluster in the C-terminal domain of the human prostaglandin receptor EP4 that is essential for agonist-induced beta-arrestin1 recruitment but differs from the apparent principal phosphorylation site
- 2004
-
Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 379:Pt 3, s. 573-585
-
Tidskriftsartikel (refereegranskat)abstract
- hEP4-R (human prostaglandin E2 receptor, subtype EP4) is a G(s)-linked heterotrimeric GPCR (G-protein-coupled receptor). It undergoes agonist-induced desensitization and internalization that depend on the presence of its C-terminal domain. Desensitization and internalization of GPCRs are often linked to agonist-induced beta-arrestin complex formation, which is stabilized by phosphorylation. Subsequently beta-arrestin uncouples the receptor from its G-protein and links it to the endocytotic machinery. The C-terminal domain of hEP4-R contains 38 Ser/Thr residues that represent potential phosphorylation sites. The present study aimed to analyse the relevance of these Ser/Thr residues for agonist-induced phosphorylation, interaction with beta-arrestin and internalization. In response to agonist treatment, hEP4-R was phosphorylated. By analysis of proteolytic phosphopeptides of the wild-type receptor and mutants in which groups of Ser/Thr residues had been replaced by Ala, the principal phosphorylation site was mapped to a Ser/Thr-containing region comprising residues 370-382, the presence of which was necessary and sufficient to obtain full agonist-induced phosphorylation. A cluster of Ser/Thr residues (Ser-389-Ser-390-Thr-391-Ser-392) distal to this site, but not the principal phosphorylation site, was essential to allow agonist-induced recruitment of beta-arrestin1. However, phosphorylation greatly enhanced the stability of the beta-arrestin1-receptor complexes. For maximal agonist-induced internalization, phosphorylation of the principal phosphorylation site was not required, but both beta-arrestin1 recruitment and the presence of Ser/Thr residues in the distal half of the C-terminal domain were necessary.
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