title: The apical and basolateral secretion of Wnt11 and Wnt3a in polarized epithelial cells is regulated by different mechanisms.
abstract: Wnts are glycan- and lipid-modified morphogens that are important for cellular responses, but how Wnts are secreted in polarized epithelial cells remains unclear. Although Wntless (Wls) has been shown to interact with Wnts and support their secretion, the role of Wls in the sorting of Wnts to the final destination in polarized epithelial cells have not been clarified. Glycosylation was shown to be important for the sorting of some transmembrane and secreted proteins, but glycan profiles and their roles in the polarized secretion of Wnts has not yet been demonstrated. Here we show the apical and basolateral secretion of Wnts is regulated by different mechanisms. Wnt11 and Wnt3a were secreted apically and basolaterally, respectively, in polarized epithelial cells. Wls was localized to the basolateral membrane. Mass-spectrometric analyses revealed that Wnt11 is modified with complex/hybrid(Asn40)-, high-mannose(Asn90)- and high-mannose/hybrid(Asn300)-type glycans and that Wnt3a is modified with two high-mannose-type glycans (Asn87 and Asn298). Glycosylation processing at Asn40 and galectin-3 were required for the apical secretion of Wnt11, whereas clathrin and adaptor protein-1 were required for the basolateral secretion of Wnt3a. By the fusion of the Asn40 glycosylation site of Wnt11, Wnt3a was secreted apically. The recycling of Wls by AP-2 was necessary for the basolateral secretion of Wnt3a but not for the apical secretion of Wnt11. These results suggest that Wls has different roles in the polarized secretion of Wnt11 and Wnt3a and that glycosylation processing of Wnts decides their secretory routes.
authors.affiliation: Department of Molecular Biology and Biochemistry, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Chihiro
authors.initials: C
authors.lastname: Awada
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hanaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakane
authors.forename: Ikuko
authors.initials: I
authors.lastname: Tsujimoto
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Takao
authors.forename: Akira
authors.initials: A
authors.lastname: Kikuchi
mesh_terms: D033962:Adaptor Protein Complex 2 / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D016764:Cell Polarity / Q000235:genetics*; D004285:Dogs; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D006020:Glycopeptides / Q000737:chemistry* / Q000378:metabolism; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D060509:Wnt3A Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D033962:Adaptor Protein Complex 2; D006020:Glycopeptides; C545200:Gpr177 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D011134:Polysaccharides; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled; D051153:Wnt Proteins; C508957:Wnt11 protein, mouse; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse
keywords: Glycosylation; Polarity; Secretion; Wnt; Wntless