The Sema domain, a protein interacting module, of semaphorin 2A (Sema2A)
Sema2A, a secreted semaphorin, signals through its receptor plexin B (PlexB) to regulate central and peripheral axon pathfinding. In the Drosophila embryo, Sema2A secreted by oenocytes interacts with PlexB to guide sensory axons. Sema2A is a member of the semaphorin family of proteins. 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.