title: Galectin-3 binds to MUC1-N-terminal domain and triggers recruitment of β-catenin in MUC1-expressing mouse 3T3 cells.
abstract: BACKGROUND
  Galectin-3 is expressed in a variety of tumors and its expression level is related with tumor progression. Aberrant expression of MUC1 in various tumors is also associated with a poor prognosis. It has been reported that MUC1 is a natural ligand of galectin-3.
  
  
  METHODS
  A stable MUC1 transfectant was produced by introducing MUC1 cDNA into mouse 3T3 fibroblasts (MUC1/3T3 cells). MUC1 was prepared from MUC1/3T3 cells; MUC1-N-terminal domain (MUC1-ND) and -C-terminal domain (MUC1-CD) were separated by CsCl ultracentrifugation, and then the galectin-3-binding domain was determined by co-immuniprecipitation assay. After ligation of galectin-3 to 3T3/MUC1 cells, MUC1-CD was immunoprecipitated from the cell lysate. The immunoprecipitate was subjected to SDS-PAGE and Western blotting, followed by detection of co-immunoprecipitated β-catenin.
  
  
  RESULTS
  Galectin-3 binds to the N-terminal domain of MUC1 but not to the C-terminal one. Galectin-3 present on the cell surface increased with the expression of MUC1 and is colocalized with MUC1. It should be noted that β-catenin was detected in the immunoprecipitate with anti-MUC1-CD Ab from a lysate of galectin-3-treated 3T3/MUC1 cells.
  
  
  CONCLUSIONS
  Galectin-3 binds to MUC1-ND and triggers MUC1-mediated signaling in 3T3/MUC1 cells, leading to recruitment of β-catenin to MUC1-CD.
  
  
  CONCLUSIONS
  This signaling may be another MUC1-mediated pathway and function in parallel with a growth factor-dependent MUC1-mediated pathway.
authors.affiliation: Department of Molecular Bioscience, Faculty of Life Science, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Tanida
authors.affiliation: Department of Molecular Bioscience, Faculty of Life Science, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan.
authors.forename: Yugo
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Department of Molecular Bioscience, Faculty of Life Science, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Ishida
authors.affiliation: Department of Molecular Bioscience, Faculty of Life Science, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Akita
authors.affiliation: Department of Molecular Bioscience, Faculty of Life Science, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan. Electronic address: hnakada@cc.kyoto-su.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakada
mesh_terms: D000818:Animals; D037502:Galectin 3 / Q000502:physiology*; D051379:Mice; D018396:Mucin-1 / Q000737:chemistry / Q000502:physiology*; D041681:NIH 3T3 Cells; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000502:physiology; D051176:beta Catenin / Q000378:metabolism*
chemical_list: C495267:CTNNB1 protein, mouse; D037502:Galectin 3; D018396:Mucin-1; D051176:beta Catenin; C577056:muc1 protein, mouse
keywords: Galectin-3; MUC1; β-Catenin