Hedgehog Signalling

AbstractHedgehog (Hh) proteins are a family of secreted factors with morphogen activities that have essential role during embryonic development and in adulthood. Mechanisms underlying the production and reception, as well as the signal transduction pathway of Hh proteins, are highly conserved between invertebrates and vertebrates. However, despite this evolutionary conservation, a major divergence is the pathway's association with primary cilia in vertebrates. Hh proteins act both as short‐range and long‐range factors in the control of cell fate specification and cell differentiation, cell proliferation, tissue patterning and morphogenesis during embryonic development. Hh proteins are also involved in tumour formation. Knowledge of this pathway has been instrumental in recent therapeutic approaches aiming at downregulating Hh signalling in cancers.Key Concepts:Hedgehog signalling is conserved during evolution.Hedgehog is a morphogen, specifying distinct cell types at different concentrations.Hedgehog acts as a short‐ and long‐range signalling molecule.Hedgehog has essential role in cell fate specification and differentiation and in cell proliferation and survival.Hedgehog signalling is implicated in cancer.