Immunoglobulin (Ig)-like domain of class III semaphorin Sema3
The members here are composed of the immunoglobulin (Ig)-like domain of Sema3 and similar proteins. Semaphorins are classified based on structural features additional to the Sema domain. Sema3 is a Class III semaphorin that is secreted. It is a vertebrate class having a Sema domain, an Ig domain, a short basic domain. 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.