PUBLICATION
Molecular dissection of Wnt3a-Frizzled8 interaction reveals essential and modulatory determinants of Wnt signaling activity
- Authors
- Kumar, S., Zigman, M., Patel, T.R., Trageser, B., Gross, J.C., Rahm, K., Boutros, M., Gradl, D., Steinbeisser, H., Holstein, T., Stetefeld, J., and Özbek, S.
- ID
- ZDB-PUB-140714-1
- Date
- 2014
- Source
- BMC Biology 12: 44 (Journal)
- Registered Authors
- Zigman, Mihaela
- Keywords
- Wnt signaling, Wnt, Frizzled, Wnt3a mutation analysis
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Embryo, Nonmammalian/metabolism
- HEK293 Cells
- Humans
- Mice
- Models, Biological
- Models, Molecular
- Molecular Sequence Data
- Mutant Proteins/metabolism
- Point Mutation/genetics
- Protein Binding
- Protein Structure, Tertiary
- Receptors, G-Protein-Coupled/chemistry*
- Receptors, G-Protein-Coupled/metabolism*
- Solubility
- Structure-Activity Relationship
- Wnt Signaling Pathway*
- Wnt3A Protein/chemistry*
- Wnt3A Protein/metabolism*
- Zebrafish/embryology
- PubMed
- 24885675 Full text @ BMC Biol.
Citation
Kumar, S., Zigman, M., Patel, T.R., Trageser, B., Gross, J.C., Rahm, K., Boutros, M., Gradl, D., Steinbeisser, H., Holstein, T., Stetefeld, J., and Özbek, S. (2014) Molecular dissection of Wnt3a-Frizzled8 interaction reveals essential and modulatory determinants of Wnt signaling activity. BMC Biology. 12:44.
Abstract
Background Wnt proteins are a family of secreted signaling molecules that regulate key developmental processes in metazoans. The molecular basis of Wnt binding to Frizzled and LRP5/6 co-receptors has long been unknown due to the lack of structural data on Wnt ligands. Only recently, the crystal structure of the Wnt8-Frizzled8-cysteine-rich-domain (CRD) complex was solved, but the significance of interaction sites that influence Wnt signaling has not been assessed.
Results Here, we present an extensive structure-function analysis of mouse Wnt3a in vitro and in vivo. We provide evidence for the essential role of serine 209, glycine 210 (site 1) and tryptophan 333 (site 2) in Fz binding. Importantly, we discovered that valine 337 in the site 2 binding loop is critical for signaling without contributing to binding. Mutations in the presumptive second CRD binding site (site 3) partly abolished Wnt binding. Intriguingly, most site 3 mutations increased Wnt signaling, probably by inhibiting Wnt-CRD oligomerization. In accordance, increasing amounts of soluble Frizzled8-CRD protein modulated Wnt3a signaling in a biphasic manner.
Conclusions We propose a concentration-dependent switch in Wnt-CRD complex formation from an inactive aggregation state to an activated high mobility state as a possible modulatory mechanism in Wnt signaling gradients.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping