Immunoglobulin (Ig)-like domain of class III semaphorin
Ig_Semaphorin_class III; Immunoglobulin (Ig)-like domain of class III semaphorins. Semaphorins are classified into various classes on the basis of structural features additional to the Sema domain. Class III semaphorins are a vertebrate class having a Sema domain, an Ig domain, a short basic domain, and are secreted. They have been shown to be axonal guidance cues and have a part in the regulation of the cardiovascular, immune and respiratory systems. Sema3A, the prototype member of this class III subfamily, induces growth cone collapse and is an inhibitor of axonal sprouting. In perinatal rat cortex, it acts as a chemoattractant and functions to direct the orientated extension of apical dendrites. It may play a role, prior to the development of apical dendrites, in signaling the radial migration of newborn cortical neurons towards the upper layers. Sema3A selectively inhibits vascular endothelial growth factor receptor (VEGF)-induced angiogenesis and induces microvascular permeability. This group also includes Sema3B, -C, -D, -E, -G.