Title : Post-translational palmitoylation and glycosylation of
Wnt-5a are necessary for its signalling
Abstract :
- Wnt-5a is a representative ligand that activates a beta-catenin-independent pathway in Wnt signalling
- In the present paper, the roles of the post-translational modifications in the actions of Wnt-5a were investigated
- We found that Wnt-5a is modified with palmitate at Cys104 and glycans at Asn114, Asn120, Asn311 and Asn325
- The palmitoylation was not essential for the secretion of Wnt-5a , but was necessary for its ability to suppress Wnt-3a-dependent T-cell factor transcriptional activity and to stimulate cell migration
- Wnt-5a activated focal adhesion kinase and this activation also required palmitoylation
- Wild-type Wnt-5a induced the internalization of Fz (Frizzled) 5 , but a Wnt-5a mutant that lacks the palmitoylation site did not
- Furthermore, the binding of Wnt-5a to the extracellular domain of Fz5 required palmitoylation of Wnt-5a
- These results indicate that palmitoylation of Wnt-5a is important for the triggering of signalling at the cell surface level and, therefore, that the lipid-unmodified form of Wnt-5a cannot activate intracellular signal cascades
- In contrast, glycosylation was necessary for the secretion of Wnt-5a , but not essential for the actions of Wnt-5a
- Thus the post-translational palmitoylation and glycosylation of Wnt-5a are important for the actions and secretion of Wnt-5a