The Sema domain, a protein interacting module, of semaphorin 3F (Sema3F)
Sema3F is coexpressed with semaphorin3B. Both Sema3B and Sema3F proteins are candidate tumor suppressors that are down-regulated in highly metastatic tumors. Two receptor families, the neuropilins and plexins, have been implicated in mediating the actions of semaphorins 3B and 3F. Sema3F is a member of the class 3 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.
Comment:Semaphorin/plexin signaling is dependent on the formation of a 2:2 heterotetramer that is composed of two plexin molecules bound to a semaphorin homodimer. Monomeric semaphorin binds plexin but does not trigger signaling.