In the absence of a Wnt signal, β-catenin is phosphorylated and targeted for degradation by the proteasome. When a Wnt ligand binds to the Frizzled receptor and its co-receptor LRP5/6, a signaling complex forms that inhibits the degradation of β-catenin. Accumulated β-catenin translocates to the nucleus, where it interacts with TCF/LEF transcription factors to activate target genes involved in cell proliferation and differentiation.