Enables glycosaminoglycan binding activity; laminin-1 binding activity; and patched binding activity. Involved in several processes, including hematopoietic or lymphoid organ development; positive regulation of T cell activation; and regulation of smooth muscle cell differentiation. Acts upstream of or within several processes, including animal organ development; limb morphogenesis; and neurogenesis. Located in several cellular components, including cell surface; extracellular space; and membrane raft. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; limb bud; and sensory organ. Used to study brachydactyly type A1 and holoprosencephaly 3. Human ortholog(s) of this gene implicated in several diseases, including Hirschsprung’s disease; holoprosencephaly (multiple); hypoplastic or aplastic tibia with polydactyly; middle cerebral artery infarction; and polydactyly. Orthologous to human SHH (sonic hedgehog signaling molecule).