title: ZNRF3 promotes Wnt receptor turnover in an R-spondin-sensitive manner.
abstract: R-spondin proteins strongly potentiate Wnt signalling and function as stem-cell growth factors. Despite the biological and therapeutic significance, the molecular mechanism of R-spondin action remains unclear. Here we show that the cell-surface transmembrane E3 ubiquitin ligase zinc and ring finger 3 (ZNRF3) and its homologue ring finger 43 (RNF43) are negative feedback regulators of Wnt signalling. ZNRF3 is associated with the Wnt receptor complex, and inhibits Wnt signalling by promoting the turnover of frizzled and LRP6. Inhibition of ZNRF3 enhances Wnt/β-catenin signalling and disrupts Wnt/planar cell polarity signalling in vivo. Notably, R-spondin mimics ZNRF3 inhibition by increasing the membrane level of Wnt receptors. Mechanistically, R-spondin interacts with the extracellular domain of ZNRF3 and induces the association between ZNRF3 and LGR4, which results in membrane clearance of ZNRF3. These data suggest that R-spondin enhances Wnt signalling by inhibiting ZNRF3. Our study provides new mechanistic insights into the regulation of Wnt receptor turnover, and reveals ZNRF3 as a tractable target for therapeutic exploration.
authors.affiliation: Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
authors.forename: Huai-Xiang
authors.initials: HX
authors.lastname: Hao
authors.forename: Yang
authors.initials: Y
authors.lastname: Xie
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Olga
authors.initials: O
authors.lastname: Charlat
authors.forename: Emma
authors.initials: E
authors.lastname: Oster
authors.forename: Monika
authors.initials: M
authors.lastname: Avello
authors.forename: Hong
authors.initials: H
authors.lastname: Lei
authors.forename: Craig
authors.initials: C
authors.lastname: Mickanin
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.forename: Heinz
authors.initials: H
authors.lastname: Ruffner
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Mao
authors.forename: Qicheng
authors.initials: Q
authors.lastname: Ma
authors.forename: Raffaella
authors.initials: R
authors.lastname: Zamponi
authors.forename: Tewis
authors.initials: T
authors.lastname: Bouwmeester
authors.forename: Peter M
authors.initials: PM
authors.lastname: Finan
authors.forename: Marc W
authors.initials: MW
authors.lastname: Kirschner
authors.forename: Jeffery A
authors.initials: JA
authors.lastname: Porter
authors.forename: Fabrizio C
authors.initials: FC
authors.lastname: Serluca
authors.forename: Feng
authors.initials: F
authors.lastname: Cong
mesh_terms: D000818:Animals; D016764:Cell Polarity / Q000502:physiology; D015179:Colorectal Neoplasms / Q000235:genetics; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D025461:Feedback, Physiological; D005260:Female; D051157:Frizzled Receptors / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D060488:Low Density Lipoprotein Receptor-Related Protein-6 / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D015513:Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D043562:Receptors, G-Protein-Coupled / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D060490:Receptors, Wnt / Q000378:metabolism*; D019699:Thrombospondins / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination; D060449:Wnt Signaling Pathway; D014981:Xenopus; D015027:Zebrafish; D051176:beta Catenin / Q000378:metabolism; D000098907:R-Spondins
chemical_list: D004268:DNA-Binding Proteins; D051157:Frizzled Receptors; D060488:Low Density Lipoprotein Receptor-Related Protein-6; D015513:Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D060490:Receptors, Wnt; D019699:Thrombospondins; D044767:Ubiquitin-Protein Ligases; D051176:beta Catenin; C411562:LGR4 protein, human; C555475:LRP6 protein, human; C503243:RSPO1 protein, human; D000098907:R-Spondins; C496945:RNF43 protein, human; C572950:ZNRF3 protein, human; C572951:Znrf3 protein, mouse