Semaphorin 3A

Semaphorin-3A (SEMA3A) is also known as Semaphorin III, which belongs to the semaphorin family. SEMA3A contains 1 Ig-like C2-type (immunoglobulin-like) domain, one PSI domain amd one sema domain. Semaphorin-3A is a secreted proteins, or chemorepulser, secreted by surrounding tissues to guide migrating cells and axons in the developing nervous system of an organism which is critical for the precise formation of neurons and vasculature. SEMA3A can function as either a chemorepulsive agent, inhibiting axonal outgrowth, or as a chemoattractive agent, stimulating the growth of apical dendrites. In both cases, the protein is vital for normal neuronal pattern development. Increased expression of SEMA3A is associated with schizophrenia and is seen in a variety of human tumor cell lines. Also, aberrant release of this protein is associated with the progression of Alzheimer's disease.