Semaphorin-7A (Sema7A) plays regulatory roles in both immune and nervous systems. Unlike other semaphorins, which act as repulsive guidance cues, Sema7A enhances central and peripheral axon growth and is required for proper axon tract formation during embryonic development []. Sema7A also plays a critical role in the negative regulation of T cell activation and function []. Sema7A is a membrane-anchored 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 [].
This entry represents the Sema domain found in Plexin-C1, which belongs to the Plexin family. Plexin family members are semaphorin receptors. Plexin C1 has been identified as the receptor of semaphorin 7A, which plays regulation roles in both the immune and nervous systems []. Unlike other semaphorins which act as repulsive guidance cues, Sema7A enhances central and peripheral axon growth and is required for proper axon tract formation during embryonic development. Plexin C1 is a potential tumor suppressor for melanoma progression. The expression of Plexin C1 is diminished or absent in human melanoma cell lines []. Cofilin, an actin-binding protein involved in cell migration, is a downstream target of Sema7A-Plexin C1 signaling. Cofilin is not phosphorylated when Plexin C1 expression is silenced. Thus, melanoma invasion and metastasis may be promoted through the loss of Plexin C1 inhibitory signaling on cofilin activation []. The Sema domain is located at the N terminus and contains four disulfide bonds formed by eight conserved cysteine residues. It serves as a ligand-recognition and -binding module.
