Post-translational palmitoylation and glycosylation of Wnt-5a are necessary for its signalling.
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.
Kurayoshi
Manabu
M
Department of Biochemistry, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551, Japan.
Yamamoto
Hideki
H
Izumi
Shunsuke
S
Kikuchi
Akira
A
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002465:Cell Movement; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D051820:TCF Transcription Factors / Q000378:metabolism; D058118:Transcription Factor 7-Like 2 Protein; D051153:Wnt Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000071818:Wnt-5a Protein
D005229:Fatty Acids, Monounsaturated; D011518:Proto-Oncogene Proteins; D051820:TCF Transcription Factors; C544894:TCF7L2 protein, human; C544895:Tcf7l2 protein, mouse; D058118:Transcription Factor 7-Like 2 Protein; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; C438615:Wnt5a protein, mouse; C008757:palmitoleic acid