Semaphorins are a large and diverse family of proteins, widely expressed across divergent animal phyla. They are secreted and membrane-associated proteins, conserved both structurally and functionally, and they are divided in eight classes (1-7 and V). They are involved in axon guidance and influence the migration of neurons and glial cells. This entry represents the C-terminal domain of Semaphorin 4F (also known as Semaphorin-W) which plays a role in visual system development and in oligodendrocyte precursor migration and differentiation. Like other Semaphorin 4 members, it includes a Ig-like domain, adjacent the PSI domain (plexin-semaphorin-integrin domain, conserved across all semaphorins) [2], a transmembrane region and a short intracellular tail. The latter is rich in proline residues similar to other transmembrane semaphorins suggesting that it may interact with cytoskeletal or signalling proteins. It also contains a cyclic nucleotide-dependent protein kinase phosphorylation site, involved in signal transduction into the cell [1-3]. Sema4F is found in glutamatergic synapses, preferentially in postsynaptic dendrites, attached to SAP90/PSD-95-scaffolding protein. Sema4F interacts with SAP90/PSD-95 PDZ domains through the critical last last three C-terminal amino acids [3,4].

1: Cloning, expression, and genetic mapping of Sema W, a member of the semaphorin family. Encinas JA, Kikuchi K, Chedotal A, de Castro F, Goodman CS, Kimura T; Proc Natl Acad Sci U S A. 1999;96:2491-2496. PMID:10051670

2: The semaphorins. Yazdani U, Terman JR; Genome Biol. 2006;7:211. PMID:16584533

3: Expression of Semaphorin 4F in neurons and brain oligodendrocytes and the regulation of oligodendrocyte precursor migration in the optic nerve. Armendariz BG, Bribian A, Perez-Martinez E, Martinez A, de Castro F, Soriano E, Burgaya F; Mol Cell Neurosci. 2012;49:54-67. PMID:21945643

4: Semaphorin4F interacts with the synapse-associated protein SAP90/PSD-95. Schultze W, Eulenburg V, Lessmann V, Herrmann L, Dittmar T, Gundelfinger ED, Heumann R, Erdmann KS; J Neurochem. 2001;78:482-489. PMID:11483650