Protein-kinase-C-mediated β-catenin phosphorylation negatively regulates the Wnt/β-catenin pathway

Normally, the Wnt/β-catenin pathway controls developmental processes and homeostasis, but abnormal activation of this pathway is a frequent event during the development of cancer. The key mechanism in regulation of the Wnt/β-catenin pathway is the amino-terminal phosphorylation of β-catenin, marking it for proteasomal degradation. Here we present small-molecule-based identification of protein kinase C (PKC)-mediated β-catenin phosphorylation as a novel mechanism regulating the Wnt/β-catenin pathway. We used a cell-based chemical screen to identify A23187, which inhibits the Wnt/β-catenin pathway. PKC was activated by A23187 treatment and subsequently phosphorylated N-terminal serine (Ser) residues of β-catenin, which promoted β-catenin degradation. Moreover, the depletion of PKCα inhibited the phosphorylation and degradation of β-catenin. Therefore, our findings suggest that the PKC pathway negatively regulates the β-catenin level outside of the Wnt/β-catenin pathway.

[1]  Jaejoon Won,et al.  Hexachlorophene Inhibits Wnt/β-Catenin Pathway by Promoting Siah-Mediated β-Catenin Degradation , 2006, Molecular Pharmacology.

[2]  Y. Jeon,et al.  Polysiphonia japonica extract suppresses the Wnt/β-catenin pathway in colon cancer cells by activation of NF-κB , 2006 .

[3]  Jaejoon Won,et al.  Diclofenac attenuates Wnt/β‐catenin signaling in colon cancer cells by activation of NF‐κB , 2005 .

[4]  G. Brabant,et al.  Wnt-5a has tumor suppressor activity in thyroid carcinoma , 2005, Oncogene.

[5]  W. Wade,et al.  Protein Kinase C‐α and ‐δ Are Required for FcαR (CD89) Trafficking to MHC Class II Compartments and FcαR‐Mediated Antigen Presentation , 2004, Traffic.

[6]  S. Chakraborti,et al.  Role of an aprotinin-sensitive protease in protein kinase Calpha-mediated activation of cytosolic phospholipase A2 by calcium ionophore (A23187) in pulmonary endothelium. , 2004, Cellular signalling.

[7]  W. Song,et al.  Modulation of β-Catenin Phosphorylation/Degradation by Cyclin-dependent Kinase 2* , 2004, Journal of Biological Chemistry.

[8]  Reinhart Heinrich,et al.  The Roles of APC and Axin Derived from Experimental and Theoretical Analysis of the Wnt Pathway , 2003, PLoS biology.

[9]  Hosoon Choi,et al.  Wnt-5a inhibits the canonical Wnt pathway by promoting GSK-3–independent β-catenin degradation , 2003, The Journal of cell biology.

[10]  R. Chandraratna,et al.  Adenomatous Polyposis Coli (APC)-independent Regulation of β-Catenin Degradation via a Retinoid X Receptor-mediated Pathway* , 2003, Journal of Biological Chemistry.

[11]  Hans Clevers,et al.  Caught up in a Wnt storm: Wnt signaling in cancer. , 2003, Biochimica et biophysica acta.

[12]  R. Moon,et al.  Dishevelled activates Ca2+ flux, PKC, and CamKII in vertebrate embryos , 2003, The Journal of cell biology.

[13]  Naoto Ueno,et al.  The TAK1-NLK Mitogen-Activated Protein Kinase Cascade Functions in the Wnt-5a/Ca2+ Pathway To Antagonize Wnt/β-Catenin Signaling , 2003, Molecular and Cellular Biology.

[14]  Edward H. Koo,et al.  Presenilin Couples the Paired Phosphorylation of β-Catenin Independent of Axin Implications for β-Catenin Activation in Tumorigenesis , 2002, Cell.

[15]  Katsuhiko Mikoshiba,et al.  The Wnt/calcium pathway activates NF-AT and promotes ventral cell fate in Xenopus embryos , 2002, Nature.

[16]  Matthias Mann,et al.  Axin-mediated CKI phosphorylation of beta-catenin at Ser 45: a molecular switch for the Wnt pathway. , 2002, Genes & development.

[17]  Xi He,et al.  Control of β-Catenin Phosphorylation/Degradation by a Dual-Kinase Mechanism , 2002, Cell.

[18]  Raymond L. White,et al.  Siah-1 mediates a novel beta-catenin degradation pathway linking p53 to the adenomatous polyposis coli protein. , 2001, Molecular cell.

[19]  J C Reed,et al.  Siah-1, SIP, and Ebi collaborate in a novel pathway for beta-catenin degradation linked to p53 responses. , 2001, Molecular cell.

[20]  P. Polakis Wnt signaling and cancer. , 2000, Genes & development.

[21]  R. Moon,et al.  The Wnt/Ca2+ pathway: a new vertebrate Wnt signaling pathway takes shape. , 2000, Trends in genetics : TIG.

[22]  R. Moon,et al.  Ca2+/Calmodulin-dependent Protein Kinase II Is Stimulated by Wnt and Frizzled Homologs and Promotes Ventral Cell Fates in Xenopus* , 2000, The Journal of Biological Chemistry.

[23]  I. Dominguez,et al.  Dorsal downregulation of GSK3beta by a non-Wnt-like mechanism is an early molecular consequence of cortical rotation in early Xenopus embryos. , 2000, Development.

[24]  K. Kinzler,et al.  PPARδ Is an APC-Regulated Target of Nonsteroidal Anti-Inflammatory Drugs , 1999, Cell.

[25]  Bruce A. Yankner,et al.  β-Trcp couples β-catenin phosphorylation-degradation and regulates Xenopus axis formation , 1999 .

[26]  Frank McCormick,et al.  β-Catenin regulates expression of cyclin D1 in colon carcinoma cells , 1999, Nature.

[27]  R. Benarous,et al.  The F-box protein β-TrCP associates with phosphorylated β-catenin and regulates its activity in the cell , 1999, Current Biology.

[28]  Stephen J. Elledge,et al.  The SCFβ-TRCP–ubiquitin ligase complex associates specifically with phosphorylated destruction motifs in IκBα and β-catenin and stimulates IκBα ubiquitination in vitro , 1999 .

[29]  M. Pagano,et al.  The human F box protein β-Trcp associates with the Cul1/Skp1 complex and regulates the stability of β-catenin , 1999, Oncogene.

[30]  Fumiaki Ito,et al.  Cytoskeletal reorganization by soluble Wnt‐3a protein signalling , 1998, Genes to cells : devoted to molecular & cellular mechanisms.

[31]  A. Sparks,et al.  Identification of c-MYC as a target of the APC pathway. , 1998, Science.

[32]  Paul Polakis,et al.  Downregulation of β-catenin by human Axin and its association with the APC tumor suppressor, β-catenin and GSK3β , 1998, Current Biology.

[33]  Akira Kikuchi,et al.  Axin, a negative regulator of the Wnt signaling pathway, forms a complex with GSK‐3β and β‐catenin and promotes GSK‐3β‐dependent phosphorylation of β‐catenin , 1998 .

[34]  Stephen W. Byers,et al.  Serine Phosphorylation-regulated Ubiquitination and Degradation of β-Catenin* , 1997, The Journal of Biological Chemistry.

[35]  Jörg Stappert,et al.  β‐catenin is a target for the ubiquitin–proteasome pathway , 1997 .

[36]  K. Kinzler,et al.  Constitutive Transcriptional Activation by a β-Catenin-Tcf Complex in APC−/− Colon Carcinoma , 1997, Science.

[37]  Hans Clevers,et al.  Activation of β-Catenin-Tcf Signaling in Colon Cancer by Mutations in β-Catenin or APC , 1997, Science.

[38]  J. Woodgett,et al.  Wingless inactivates glycogen synthase kinase‐3 via an intracellular signalling pathway which involves a protein kinase C. , 1996, The EMBO journal.

[39]  D. Melton,et al.  A molecular mechanism for the effect of lithium on development. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[40]  A. Newton,et al.  Protein Kinase C: Structure, Function, and Regulation (*) , 1995, The Journal of Biological Chemistry.

[41]  G. Martiny-Baron,et al.  Selective inhibition of protein kinase C isozymes by the indolocarbazole Gö 6976. , 1993, The Journal of biological chemistry.

[42]  R. Roeder,et al.  Accurate transcription initiation by RNA polymerase II in a soluble extract from isolated mammalian nuclei. , 1983, Nucleic acids research.

[43]  K. Kinzler,et al.  PPAR d Is an APC-Regulated Target of Nonsteroidal Anti-Inflammatory Drugs , 1999 .

[44]  S. Elledge,et al.  The SCF–ubiquitin ligase complex associates specifically with phosphorylated destruction motifs in IkBa and b-catenin and stimulates IkBa ubiquitination in vitro , 1999 .

[45]  R. Nusse,et al.  Mechanisms of Wnt signaling in development. , 1998, Annual review of cell and developmental biology.