Regulation of immune responses by "Immune Semaphorins"
The semaphorin family contains soluble and membrane-bound proteins that were first identified as axonal guidance cues that function during neuronal development. However, cumulative findings suggest that semaphorins also play diverse roles in processes that are unrelated to axon guidance, including organogenesis, vascularization, angiogenesis, apoptosis and neoplastic transformation. After we discovered that CD100/Sema4D participates in the immune system, we have found that a subset of semaphorins called the 'Immune Semaphorins' also function in the immune system. These include Sema4A, CD100/Sema4D, Sema6D, and Sema7A. In addition, we found recently that Sema3A plays an essential role in the migration of dendritic cells (Fig. 2). We are currently studying the molecular mechanisms by which semaphorins and their receptors regulate immune responses.
Figure 1. Representative immune semaphorins. The involvement of these semaphorins in immune responses has been demonstrated by using gene-targeted mice.
Figure 2. Sema3A is important in the migration of DCs.