Semaphorin-4G is the least characterized of the seven known Class 4 transmembrane semaphorin glycoproteins. Class 4 semaphorins play multiple roles in cell attraction or repulsion, such as development of nerve pathways in the brain, promoting or inhibiting proliferation, in some cases organizing immune cell interactions. Semaphorin-4G can be expressed early in development in the central and peripheral nervous systems and in sensory ograns, such as cochlea, olfactory epithelium, vomeronasal organ and retina. In adults, Semaphorin-4G can be found in liver,kidney and brain. The human Semaphorin-4G precursor consists of a 17 amino acids signal sequence, a 658 amino acids extracellular domain, a 21 amino acids transmembrane domain, a 142 amino acids cytoplasmic domain with one Ser/Thr phosphorylation site.