The spatzles are a family of secreted proteins that share a neutrotrophin-like cystine-knot domain. Proteolytically activated, spz binds Tl and activates canonical Toll signaling in embryonic dorsal-ventral patterning and innate immunity. spz, spz5 and NT1 are more closely related to each other and to the vertebrate neurotrophins than other members of the spatzle family and some family members have neutrophin-like activity. (Adpated from FBrf0206302).