title: Hedgehog: functions and mechanisms.
abstract: The Hedgehog (Hh) family of proteins control cell growth, survival, and fate, and pattern almost every aspect of the vertebrate body plan. The use of a single morphogen for such a wide variety of functions is possible because cellular responses to Hh depend on the type of responding cell, the dose of Hh received, and the time cells are exposed to Hh. The Hh gradient is shaped by several proteins that are specifically required for Hh processing, secretion, and transport through tissues. The mechanism of cellular response, in turn, incorporates multiple feedback loops that fine-tune the level of signal sensed by the responding cells. Germline mutations that subtly affect Hh pathway activity are associated with developmental disorders, whereas somatic mutations activating the pathway have been linked to multiple forms of human cancer. This review focuses broadly on our current understanding of Hh signaling, from mechanisms of action to cellular and developmental functions. In addition, we review the role of Hh in the pathogenesis of human disease and the possibilities for therapeutic intervention.
authors.affiliation: Department of Molecular Medicine, National Public Health Institute (KTL), and Genome-Scale Biology Program, Biomedicum Helsinki, Institute of Biomedicine and High Throughput Center, Faculty of Medicine, University of Helsinki, Helsinki FI-00014, Finland.
authors.forename: Markku
authors.initials: M
authors.lastname: Varjosalo
authors.forename: Jussi
authors.initials: J
authors.lastname: Taipale
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D019070:Cell Lineage / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D053823:Hedgehog Proteins / Q000502:physiology*; D006801:Humans
chemical_list: D053823:Hedgehog Proteins