A complex signaling pathway whose name is derived from the drosophila Wg gene, which when mutated results in the wingless phenotype, and the vertebrate INT gene, which is located near integration sites of MOUSE MAMMARY TUMOR VIRUS. The signaling pathway is initiated by the binding of wnt proteins to cells surface WNT RECEPTORS which interact with the axin signaling complex and an array of second messengers that influence the actions of beta catenin.