Plexin A2 serves as a receptor for class 6 semaphorins. Interactions between Plexin A2, A4 and semaphorins 6A and 6B control the lamina-restricted projection of hippocampal mossy fibres. Sema6B also repels the growth of mossy fibres in a Plexin A4 dependent manner [, ]. Plexin A2 does not suppress Sema6B function. In addition, studies have shown that Plexin A2 may be related to anxiety and other psychiatric disorders []. Semaphorins are regulatory molecules in the development of the nervous system and in axonal guidance. They also play important roles in other biological processes, such as angiogenesis, immune regulation, respiration systems and cancer. The Sema domain is located at the N terminus and contains four disulfide bonds formed by eight conserved cysteine residues. It serves as a receptor-recognition and -binding module [].
