<p>This domain is found at C terminus of various plexins (e.g. <db_xref db="SWISSPROT" dbkey="P51805"/>). Plexins are receptors for semaphorins, and plexin signalling is important in pathfinding and patterning of both neurons and developing blood vessels [<cite idref="PUB00020942"/>, <cite idref="PUB00020835"/>]. The cytoplasmic region, which has been called a SEX domain [<cite idref="PUB00020921"/>], and is involved in downstream signalling pathways, by interaction with proteins such as Rac1, RhoD, Rnd1 and other plexins [<cite idref="PUB00020833"/>]. </p>