Dataset Information

CXCR7: a ?-arrestin-biased receptor that potentiates cell migration and recruits ?-arrestin2 exclusively through G?? subunits and GRK2.

ABSTRACT: Background: Some chemokine receptors referred to as atypical chemokine receptors (ACKRs) are thought to non-signaling decoys because of their inability to activate typical G-protein signaling pathways. CXCR7, also known as ACKR3, binds to only two chemokines, SDF-1? and I-TAC, and recruits ?-arrestins. SDF-1? also binds to its own conventional receptor, CXCR4, involving in homeostatic modulation such as development and immune surveillance as well as pathological conditions such as inflammation, ischemia, and cancers. Recently, CXCR7 is suggested as a key therapeutic target together with CXCR4 in such conditions. However, the molecular mechanisms underlying cellular responses and functional relation with CXCR7 and CXCR4 have not been elucidated, despite massive studies. Therefore, we aimed to reveal the molecular networks of CXCR7 and CXCR4 and compare their effects on cell migration.

Methods: Base on structural complementation assay using NanoBiT technology, we characterized the distinct mechanisms underlying ?-arrestin2 recruitment by both CXCR4 and CXCR7. Crosslinking and immunoprecipitation were conducted to analyze complex formation of the receptors. Gene deletion using CRISPR and reconstitution of the receptors were applied to analysis of ligand-dependent ERK phosphorylation and cell migration. All experiments were performed in triplicate and repeated more than three times. Unpaired Student's t-tests or ANOVA using PRISM5 software were employed for statistical analyses.

Results: Ligand binding to CXCR7 does not result in activation of typical signaling pathways via G? subunits but activation of GRK2 via ?? subunits and receptor phosphorylation with subsequent ?-arrestin2 recruitment. In contrast, CXCR4 induced G?_i activation and recruited ?-arrestin2 through C-terminal phosphorylation by both GRK2 and GRK5. SDF-1?-stimulated ERK phosphorylation was facilitated by CXCR4, but not CXCR7. Heterodimerization of CXCR4 and CXCR7 was not confirmed in this study, while homodimerization of them was verified by crosslinking experiment and NanoBiT assay. Regarding chemotaxis, SDF-1?-stimulated cell migration was mediated by both CXCR4 and CXCR7.

Conclusion: This study demonstrates that SDF-1?-stimulated CXCR7 mediates ?-arrestin2 recruitment via different molecular networking from that of CXCR4. CXCR7 may be neither a simple scavenger nor auxiliary receptor but plays an essential role in cell migration through cooperation with CXCR4.

SUBMITTER: Nguyen HT

PROVIDER: S-EPMC7686738 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

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CXCR7: a β-arrestin-biased receptor that potentiates cell migration and recruits β-arrestin2 exclusively through Gβγ subunits and GRK2.

Nguyen Huong Thi HT Reyes-Alcaraz Arfaxad A Yong Hyo Jeong HJ Nguyen Lan Phuong LP Park Hee-Kyung HK Inoue Asuka A Lee Cheol Soon CS Seong Jae Young JY Hwang Jong-Ik JI

Cell & bioscience 20201123 1

<h4>Background</h4>Some chemokine receptors referred to as atypical chemokine receptors (ACKRs) are thought to non-signaling decoys because of their inability to activate typical G-protein signaling pathways. CXCR7, also known as ACKR3, binds to only two chemokines, SDF-1α and I-TAC, and recruits β-arrestins. SDF-1α also binds to its own conventional receptor, CXCR4, involving in homeostatic modulation such as development and immune surveillance as well as pathological conditions such as inflamm ...[more]

PMID: 33292475

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Project description:Chemokine CXCL12 promotes growth and metastasis of more than 20 different human cancers, as well as pathogenesis of other common diseases. CXCL12 binds two different receptors, CXCR4 and CXCR7, both of which recruit and signal through the cytosolic adapter protein ?-arrestin 2. Differences in CXCL12-dependent recruitment of ?-arrestin 2 in cells expressing one or both receptors remain poorly defined. To quantitatively investigate parameters controlling association of ?-arrestin 2 with CXCR4 or CXCR7 in cells co-expressing both receptors, we used a systems biology approach combining real-time, multi-spectral luciferase complementation imaging with computational modeling. Cells expressing only CXCR4 maintain low basal association with ?-arrestin 2, and CXCL12 induces a rapid, transient increase in this interaction. In contrast, cells expressing only CXCR7 have higher basal association with ?-arrestin 2 and exhibit more gradual, prolonged recruitment of ?-arrestin 2 in response to CXCL12. We developed and fit a data-driven computational model for association of either CXCR4 or CXCR7 with ?-arrestin 2 in cells expressing only one type of receptor. We then experimentally validated model predictions that co-expression of CXCR4 and CXCR7 on the same cell substantially decreases both the magnitude and duration of CXCL12-regulated recruitment of ?-arrestin 2 to CXCR4. Co-expression of both receptors on the same cell only minimally alters recruitment of ?-arrestin 2 to CXCR7. In silico experiments also identified ?-arrestin 2 as a limiting factor in cells expressing both receptors, establishing that CXCR7 wins the "competition" with CXCR4 for CXCL12 and recruitment of ?-arrestin 2. These results reveal how competition for ?-arrestin 2 controls integrated responses to CXCL12 in cells expressing both CXCR4 and CXCR7. These results advance understanding of normal and pathologic functions of CXCL12, which is critical for developing effective strategies to target these pathways therapeutically.

Dataset Information

CXCR7: a ?-arrestin-biased receptor that potentiates cell migration and recruits ?-arrestin2 exclusively through G?? subunits and GRK2.

Publications

CXCR7: a β-arrestin-biased receptor that potentiates cell migration and recruits β-arrestin2 exclusively through Gβγ subunits and GRK2.

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