Discovery of semaphorin receptors, neuropilin and plexin, and their functions in neural development

The semaphorin receptors neuropilin and plexin were initially identified as antigens for monoclonal antibodies MAb-A5 and MAb-B2, which bind to specific neuropiles and plexiform layers within the Xenopus tadpole nervous systems, several years before the discovery of the first semaphorin. This article provides an overview of how neuropilin and plexin were discovered. In addition, it describes the functions of neuropilin in the signaling of chemorepulsive activities of class 3 semaphorins and roles of neuropilin-mediated semaphorin activities in the directional guidance of the peripheral nervous system (PNS) and integration of the peripheral ganglia.