Binds to plexin family members and plays an important role in the regulation of developmental processes. Required for normal cardiovascular development during embryogenesis. Functions as attractant for growing axons, and thereby plays an important role in axon growth and axon guidance. Interacts with PLXND1. Expressed from day 10 in the embryo. Maximum expression between days 10-12 with moderate levels from day 13 until birth. Perinatal lethality. Mice display severe defects in cardiovascular development, including aortic arch malformations and septation defects in the cardiac outflow tract. Belongs to the semaphorin family.