Participates in the Wnt signaling pathway. Activates transcription of target genes in the presence of CTNNB1 and EP300. May play a role in hair cell differentiation and follicle morphogenesis. TLE1, TLE2, TLE3 and TLE4 repress transactivation mediated by LEF1 and CTNNB1 (By similarity). Regulates T-cell receptor alpha enhancer function. Binds DNA in a sequence-specific manner. PIASG antagonizes both Wnt-dependent and Wnt-independent activation by LEF1.