This gene encodes a member of the serine/threonine kinase family of enzymes. This family member is similar to a Drosophila protein that plays a key role in the Hedgehog signaling pathway. This human protein is a positive regulator of the GLI zinc-finger transcription factors. Knockout studies of the homologous mouse gene suggest that defects in this human gene may lead to congenital hydrocephalus, possibly due to a functional defect in motile cilia. Because Hedgehog signaling is frequently activated in certain kinds of gastrointestinal cancers, it has been suggested that this gene is a target for the treatment of these cancers. Alternative splicing of this gene results in multiple transcript variants. [From RefSeq]