title: Complex cell signaling molecules from ancient molecular glue.
abstract: In this issue of Structure, Springer and colleagues argue that ancient extracellular domains of archaea involved in primitive cell adhesion have evolved into the extracellular domains of cell signaling molecules essential for the survival of animals and humans.
authors.affiliation: Biological Sciences, Queen Mary, University of London, United Kingdom.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Pickersgill
mesh_terms: D000818:Animals; D001105:Archaea / Q000378:metabolism*; D006801:Humans; D015398:Signal Transduction