title: Dishevelled stability is positively regulated by PKCζ-mediated phosphorylation induced by Wnt agonists.
abstract: Dishevelled (Dvl) proteins are central mediators of both canonical and non-canonical Wnt signaling. It is well known that, upon Wnt stimulation, Dvl becomes phosphorylated. However, how Wnt-induced phosphorylation of Dvl is regulated and its consequences are poorly understood. Here we found that Dvl proteins are overexpressed in colon cancer cells. In addition, we found that Wnt3a treatment rapidly induces hyperphosphorylation and stabilization of Dvl2 and Dvl3. The latter can be blocked by inhibition of Protein Kinase C (PKC)α, PKCδ, and PKCζ isoforms. We also found that Wnt3a-induced phosphorylation of Dvl3 by PKCζ is required to avoid Dvl3 degradation via proteasome. This demonstrated, to our knowledge for the first time, that hyperphosphorylation of Dvl by PKCζ results in Dvl stabilization. This is clear contrast with the consequences reported to date of CK1δ/ε-mediated Dvl phosphorylation upon Wnt treatment. Mapping the interaction domain between PKCζ and Dvl3 indicated that, although the Dvl-DIX domain is required to stabilize PKCζ-phosphorylated Dvl, it is not the region phosphorylated by this kinase. Our data show that the Dvl-DEP domain, required for specific interaction with PKCζ, is the site phosphorylated by this kinase, and also probably the Dvl-C terminus. Our findings suggest a model of positive regulation of PKCζ-mediated Dvl signaling activity, to produce a strong and sustained response to Wnt3a treatment by stabilizing Dvl protein levels.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.
authors.forename: Dora M
authors.initials: DM
authors.lastname: Velázquez
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Castañeda-Patlán
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico. Electronic address: rmartha@unam.mx.
authors.forename: Martha
authors.initials: M
authors.lastname: Robles-Flores
mesh_terms: D003110:Colonic Neoplasms / Q000235:genetics* / Q000473:pathology; D000072261:Dishevelled Proteins / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D025941:Protein Interaction Mapping; D011493:Protein Kinase C / Q000235:genetics* / Q000378:metabolism; D051571:Protein Kinase C-alpha / Q000235:genetics; D051745:Protein Kinase C-delta / Q000235:genetics; D059748:Proteolysis / Q000187:drug effects; D060449:Wnt Signaling Pathway / Q000187:drug effects; D060509:Wnt3A Protein / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism; D000099221:Protein Kinase C zeta
chemical_list: D000072261:Dishevelled Proteins; D046988:Proteasome Endopeptidase Complex; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D060509:Wnt3A Protein; D000099221:Protein Kinase C zeta; C000606581:DVL2 protein, human; C000606584:DVL3 protein, human; C555510:WNT3A protein, human; C496628:PRKCA protein, human
keywords: Atypical protein kinase C ζ; Dishevelled; Dvl phosphorylation; Dvl stability; Wnt signaling