Wnt5a: its signalling, functions and implication in diseases

Wnt5a is a representative ligand that activates the beta-catenin-independent pathways. Because the beta-catenin-independent pathway includes multiple signalling cascades in addition to the planar cell polarity and Ca2+ pathway, Wnt5a regulates a variety of cellular functions, such as proliferation, differentiation, migration, adhesion and polarity. Consistent with the multiple functions of Wnt5a signalling, Wnt5a knockout mice show various phenotypes, including an inability to extend the embryonic anteriorposterior and proximaldistal axes in outgrowth tissues. Thus, many important roles of Wnt5a in developmental processes have been demonstrated. Moreover, recent reports suggest that the postnatal abnormalities in the Wnt5a signalling are involved in various diseases, such as cancer, inflammatory diseases and metabolic disorders. Therefore, Wnt5a and its signalling pathways could be important targets for the diagnosis and therapy for human diseases.