Galectin-3, a novel binding partner of β-catenin

Abstract

Galectin-3 (gal-3), a pleiotrophic protein, is an important regulator of tumor metastasis, which like β-catenin shuttles between the nucleus and the cytosol in a phosphorylation-dependent manner. We report herein that β-catenin stimulation of cyclin D1 and c-myc expression is gal-3 dependent. Gal-3 binds to β-catenin/Tcf complex, colocalizes with β-catenin in the nucleus, and induces the transcriptional activity of Tcf-4 as determined by the TOP/FOPFLASH reporter system. We have identified the β-catenin-gal-3-binding sequences, which are in the NH2 and COOH termini of the proteins encompassing amino acid residues 1 to 131 and 143 to 250, respectively. These data indicate that gal-3 is a novel binding partner for β-catenin involved in the regulation of Wnt/β-catenin signaling pathway.