Semaphorin 4A: Proteins and Enzymes

The Semaphorins make up the largest family of axon guidance cues yet described. Semaphorins are divided into 8 classes (classes 3-7 found in vertebrates). Class 3 Semaphorins are secreted, classes 4 through 6 are transmembrane proteins, and class 7 are membrane associated via glycosylphosphatidylinositol (GPI) linkage. They are characterized structurally by a conserved ~400 amino acid sema domain. They are classically described as collapsing factors and mediators of axon repulsion, although ...