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Structure and functional properties of Norrin mimic Wnt for signalling with Frizzled4, Lrp5/6, and proteoglycan.

Chang TH, Hsieh FL, Zebisch M, Harlos K, Elegheert J, Jones EY - Elife (2015)

Bottom Line: These results explain numerous disease-associated mutations.Comparison with the Xenopus Wnt8-mouse Fz8CRD complex reveals Norrin mimics Wnt for Frizzled recognition.The production and characterization of wild-type and mutant Norrins reported here open new avenues for the development of therapeutics to combat abnormal Norrin/Wnt signalling.

View Article: PubMed Central - PubMed

Affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.

ABSTRACT
Wnt signalling regulates multiple processes including angiogenesis, inflammation, and tumorigenesis. Norrin (Norrie Disease Protein) is a cystine-knot like growth factor. Although unrelated to Wnt, Norrin activates the Wnt/β-catenin pathway. Signal complex formation involves Frizzled4 (Fz4), low-density lipoprotein receptor related protein 5/6 (Lrp5/6), Tetraspanin-12 and glycosaminoglycans (GAGs). Here, we report crystallographic and small-angle X-ray scattering analyses of Norrin in complex with Fz4 cysteine-rich domain (Fz4CRD), of this complex bound with GAG analogues, and of unliganded Norrin and Fz4CRD. Our structural, biophysical and cellular data, map Fz4 and putative Lrp5/6 binding sites to distinct patches on Norrin, and reveal a GAG binding site spanning Norrin and Fz4CRD. These results explain numerous disease-associated mutations. Comparison with the Xenopus Wnt8-mouse Fz8CRD complex reveals Norrin mimics Wnt for Frizzled recognition. The production and characterization of wild-type and mutant Norrins reported here open new avenues for the development of therapeutics to combat abnormal Norrin/Wnt signalling.

No MeSH data available.


Related in: MedlinePlus

Structural comparison of Norrin–Fz4CRD complex with MBP-Norrin.(A) Superposition of MBP-Norrin (green; PDB ID: 4MY2) onto Norrin in the Norrin (magenta)–Fz4CRD (blue)–SOS (wheat) and methylated Norrin (yellow)–Fz4CRD (cyan) complex structures. (B) Close-up view of steric clashes (indicated by a red arrow) between Fz4CRD and MBP.DOI:http://dx.doi.org/10.7554/eLife.06554.018
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fig4s4: Structural comparison of Norrin–Fz4CRD complex with MBP-Norrin.(A) Superposition of MBP-Norrin (green; PDB ID: 4MY2) onto Norrin in the Norrin (magenta)–Fz4CRD (blue)–SOS (wheat) and methylated Norrin (yellow)–Fz4CRD (cyan) complex structures. (B) Close-up view of steric clashes (indicated by a red arrow) between Fz4CRD and MBP.DOI:http://dx.doi.org/10.7554/eLife.06554.018

Mentions: Neither Norrin nor Fz4CRD undergoes large conformational changes upon complex formation, although the flexibility of residues involved in the binding interface is reduced (Figure 4—figure supplement 3). Interestingly, superposition of the Norrin–Fz4CRD complex and the previously reported MBP-Norrin structure resulted in steric clashes between the Fz4CRD and the MBP (Figure 4—figure supplement 4). This suggests that MBP hinders Norrin interaction with Fz4CRD consistent with MBP-Norrin only having half of the signalling activity of untagged Norrin (Ke et al., 2013).


Structure and functional properties of Norrin mimic Wnt for signalling with Frizzled4, Lrp5/6, and proteoglycan.

Chang TH, Hsieh FL, Zebisch M, Harlos K, Elegheert J, Jones EY - Elife (2015)

Structural comparison of Norrin–Fz4CRD complex with MBP-Norrin.(A) Superposition of MBP-Norrin (green; PDB ID: 4MY2) onto Norrin in the Norrin (magenta)–Fz4CRD (blue)–SOS (wheat) and methylated Norrin (yellow)–Fz4CRD (cyan) complex structures. (B) Close-up view of steric clashes (indicated by a red arrow) between Fz4CRD and MBP.DOI:http://dx.doi.org/10.7554/eLife.06554.018
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4497409&req=5

fig4s4: Structural comparison of Norrin–Fz4CRD complex with MBP-Norrin.(A) Superposition of MBP-Norrin (green; PDB ID: 4MY2) onto Norrin in the Norrin (magenta)–Fz4CRD (blue)–SOS (wheat) and methylated Norrin (yellow)–Fz4CRD (cyan) complex structures. (B) Close-up view of steric clashes (indicated by a red arrow) between Fz4CRD and MBP.DOI:http://dx.doi.org/10.7554/eLife.06554.018
Mentions: Neither Norrin nor Fz4CRD undergoes large conformational changes upon complex formation, although the flexibility of residues involved in the binding interface is reduced (Figure 4—figure supplement 3). Interestingly, superposition of the Norrin–Fz4CRD complex and the previously reported MBP-Norrin structure resulted in steric clashes between the Fz4CRD and the MBP (Figure 4—figure supplement 4). This suggests that MBP hinders Norrin interaction with Fz4CRD consistent with MBP-Norrin only having half of the signalling activity of untagged Norrin (Ke et al., 2013).

Bottom Line: These results explain numerous disease-associated mutations.Comparison with the Xenopus Wnt8-mouse Fz8CRD complex reveals Norrin mimics Wnt for Frizzled recognition.The production and characterization of wild-type and mutant Norrins reported here open new avenues for the development of therapeutics to combat abnormal Norrin/Wnt signalling.

View Article: PubMed Central - PubMed

Affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.

ABSTRACT
Wnt signalling regulates multiple processes including angiogenesis, inflammation, and tumorigenesis. Norrin (Norrie Disease Protein) is a cystine-knot like growth factor. Although unrelated to Wnt, Norrin activates the Wnt/β-catenin pathway. Signal complex formation involves Frizzled4 (Fz4), low-density lipoprotein receptor related protein 5/6 (Lrp5/6), Tetraspanin-12 and glycosaminoglycans (GAGs). Here, we report crystallographic and small-angle X-ray scattering analyses of Norrin in complex with Fz4 cysteine-rich domain (Fz4CRD), of this complex bound with GAG analogues, and of unliganded Norrin and Fz4CRD. Our structural, biophysical and cellular data, map Fz4 and putative Lrp5/6 binding sites to distinct patches on Norrin, and reveal a GAG binding site spanning Norrin and Fz4CRD. These results explain numerous disease-associated mutations. Comparison with the Xenopus Wnt8-mouse Fz8CRD complex reveals Norrin mimics Wnt for Frizzled recognition. The production and characterization of wild-type and mutant Norrins reported here open new avenues for the development of therapeutics to combat abnormal Norrin/Wnt signalling.

No MeSH data available.


Related in: MedlinePlus