Post-translational palmitoylation and glycosylation of Wnt-5a are necessary for its signalling

• Published in: Biochemical journal Vol. 402; no. 3; pp. 515 - 523
• Main Authors: Kurayoshi, Manabu, Yamamoto, Hideki, Izumi, Shunsuke, Kikuchi, Akira
• Format: Journal Article
• Language: English
• Published: England Portland Press Ltd 15.03.2007
• Subjects: Amino Acid Sequence; Animals; Cell Line; Cell Movement; Fatty Acids, Monounsaturated - metabolism; Glycosylation; Humans; Mice; Molecular Sequence Data; Protein Binding; Protein Processing, Post-Translational; Proto-Oncogene Proteins - chemistry; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins - isolation & purification; Proto-Oncogene Proteins - metabolism; Sequence Alignment; Signal Transduction; TCF Transcription Factors - metabolism; Transcription Factor 7-Like 2 Protein; Wnt Proteins - chemistry; Wnt Proteins - genetics; Wnt Proteins - isolation & purification; Wnt Proteins - metabolism; Wnt-5a Protein
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/BJ20061476

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.