– emaphorin-3A is a secreted protein which belongs to the semaphorin family. Semaphorins are a family of secreted and cell-bound signaling molecules defined by the presence of a common 500 aa Sema domain.This protein 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 this protein is associated with schizophrenia and is seen in a variety of human tumor cell lines.