Semaphorin 4F (Sema4F; also Sema W) is a 90-100 kDa, class IV member of the semaphorin family of proteins. It is expressed by select cell types, including Schwann cells and neurons, and likely acts as an inhibitor of cell proliferation by Schwann cells, and a regulator of postsynaptic glutamatergic synapses on neuron dendrites. Mature mouse Sema4F is a type I transmembrane protein that is 737 amino acids (aa) in length. It contains a 627 aa extracellular region (aa 41-667) that is characterized by the presence of one Sema domain (aa 71-493), a PSI region (aa 518-569), and a C2-type Ig-like domain (aa 586-641). Over aa 41-667, mouse Sema4F shares 92% and 98% aa identity with human and rat Sema4F, respectively.
