Reactome: A Curated Pathway Database

Sema4D in semaphorin signaling (R-HSA-400685)

Species Homo sapiens

Summation

Semaphorin 4D (Sema 4D/CD100) is an axon guidance molecule with two disulfide-linked 150-kDa subunits. SEMA4D is structurally defined by a conserved 500-amino acid extracellular domain with 16 cysteines (sema domain) and also an Ig-like domain C-terminal to the sema domain. Sema4D is expressed on the cell surface as a homodimer; cysteine 679 within the sema domain is required for this dimerization.
The main receptors for Sema4D are plexin-B1 and CD72. The activation of plexins by semaphorins initiates a variety of signaling processes that involve several small GTPases of the Ras and Rho families. Sema4D-Plexin-B1 interaction appears to mediate different and sometimes opposite effects depending on the cellular context. Plexin-B1 activation inhibits integrin-mediated cell attachment and cell migration through the activation of the R-RasGAP activity inherent to plexin-B1 or through the inhibition of RhoA. However, activation of plexin-B1 by Sema4D stimulates the migration of endothelial cells by mediating the activation of RhoA.

Locations in the PathwayBrowser
Literature References
pubMedId Title Journal Year
14770294 Biological functions and signaling of a transmembrane semaphorin, CD100/Sema4D Cell Mol Life Sci 2004
16314868 Semaphorins command cells to move Nat Rev Mol Cell Biol 2005
15818466 Plexins: axon guidance and signal transduction Cell Mol Life Sci 2005
14770294 Biological functions and signaling of a transmembrane semaphorin, CD100/Sema4D Cell Mol Life Sci 2004