The Sema domain occurs in semaphorins, which are a large family of secreted and transmembrane proteins, some of which function as repellent signals during axon guidance. Sema domains also occur in Swiss:P08581 the hepatocyte growth factor receptor and Swiss:P51805

1: Plexin A is a neuronal semaphorin receptor that controls axon guidance. Winberg ML, Noordermeer JN, Tamagnone L, Comoglio PM, Spriggs MK, Tessier-Lavigne M, Goodman CS; Cell 1998;95:903-916. PMID:9875845