LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands

Abstract LGR4 and LGR5 are two homologous receptors that potentiate Wnt/β-catenin signaling in response to R-spondin (RSPO) ligands. The RSPO and LGR4 complex binds to and inhibits activities of two related E3 ubiquitin ligases, RNF43 and ZNRF3, and thus protects Wnt receptors from the E3 ligase-med...

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Main Authors: Yukimatsu Toh, Ling Wu, Soohyun Park, Allison Wang, Jianghua Tu, Wangsheng Yu, Mingxin Zuo, Kendra S. Carmon, Qingyun J. Liu
Format: Article
Language:English
Published: Nature Portfolio 2023-07-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-023-37856-w
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author Yukimatsu Toh
Ling Wu
Soohyun Park
Allison Wang
Jianghua Tu
Wangsheng Yu
Mingxin Zuo
Kendra S. Carmon
Qingyun J. Liu
author_facet Yukimatsu Toh
Ling Wu
Soohyun Park
Allison Wang
Jianghua Tu
Wangsheng Yu
Mingxin Zuo
Kendra S. Carmon
Qingyun J. Liu
author_sort Yukimatsu Toh
collection DOAJ
description Abstract LGR4 and LGR5 are two homologous receptors that potentiate Wnt/β-catenin signaling in response to R-spondin (RSPO) ligands. The RSPO and LGR4 complex binds to and inhibits activities of two related E3 ubiquitin ligases, RNF43 and ZNRF3, and thus protects Wnt receptors from the E3 ligase-mediated degradation. The RSPO and LGR5 complex, however, does not interact with the E3 ligases, and the structural basis of this difference remained unknown. Here we examined the affinities of monovalent and bivalent RSPO ligands in binding to LGR4, RNF43/ZNRF3, and LGR5 in whole cells and found unique features among the receptors and E3 ligases. Monovalent RSPO2 furin domain had much lower affinity in binding to LGR4 or RNF43/ZNRF3 than the bivalent form. In contrast, monovalent and bivalent forms had nearly identical affinity in binding to LGR5. Co-expression of ZNRF3 with LGR4 led to much higher binding affinity of the monovalent form whereas co-expression of ZNRF3 with LGR5 had no effect on the affinity. These results suggest that LGR4 and RNF43/ZNRF3 form a 2:2 dimer that accommodates bivalent binding of RSPO whereas LGR5 forms a homodimer that does not. Structural models are proposed to illustrate how RSPOs bind to LGR4, RNF43/ZNRF3, and LGR5 in whole cells.
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spelling doaj.art-bac99d20d61a474cb90d937a87d04cd92023-07-09T11:14:33ZengNature PortfolioScientific Reports2045-23222023-07-0113111010.1038/s41598-023-37856-wLGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligandsYukimatsu Toh0Ling Wu1Soohyun Park2Allison Wang3Jianghua Tu4Wangsheng Yu5Mingxin Zuo6Kendra S. Carmon7Qingyun J. Liu8Center for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonCenter for Translational Cancer Research, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at HoustonAbstract LGR4 and LGR5 are two homologous receptors that potentiate Wnt/β-catenin signaling in response to R-spondin (RSPO) ligands. The RSPO and LGR4 complex binds to and inhibits activities of two related E3 ubiquitin ligases, RNF43 and ZNRF3, and thus protects Wnt receptors from the E3 ligase-mediated degradation. The RSPO and LGR5 complex, however, does not interact with the E3 ligases, and the structural basis of this difference remained unknown. Here we examined the affinities of monovalent and bivalent RSPO ligands in binding to LGR4, RNF43/ZNRF3, and LGR5 in whole cells and found unique features among the receptors and E3 ligases. Monovalent RSPO2 furin domain had much lower affinity in binding to LGR4 or RNF43/ZNRF3 than the bivalent form. In contrast, monovalent and bivalent forms had nearly identical affinity in binding to LGR5. Co-expression of ZNRF3 with LGR4 led to much higher binding affinity of the monovalent form whereas co-expression of ZNRF3 with LGR5 had no effect on the affinity. These results suggest that LGR4 and RNF43/ZNRF3 form a 2:2 dimer that accommodates bivalent binding of RSPO whereas LGR5 forms a homodimer that does not. Structural models are proposed to illustrate how RSPOs bind to LGR4, RNF43/ZNRF3, and LGR5 in whole cells.https://doi.org/10.1038/s41598-023-37856-w
spellingShingle Yukimatsu Toh
Ling Wu
Soohyun Park
Allison Wang
Jianghua Tu
Wangsheng Yu
Mingxin Zuo
Kendra S. Carmon
Qingyun J. Liu
LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands
Scientific Reports
title LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands
title_full LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands
title_fullStr LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands
title_full_unstemmed LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands
title_short LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands
title_sort lgr4 and lgr5 form distinct homodimers that only lgr4 complexes with rnf43 znrf3 to provide high affinity binding of r spondin ligands
url https://doi.org/10.1038/s41598-023-37856-w
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