Neuregulins in schwann cell development

In the PNS, Schwann cells are important both as support cells for small, unmyelinated axons, and for support and the production of myelin sheaths around larger axons, thereby permitting rapid axonal conduction. During development, successful myelination requires that Schwann cell precursors develop from multipotential cells within the neural crest, avoid apoptotic cell death, migrate with developing nerves, proliferate, and, finally, mature into myelinating Schwann cells. Recently, the important role of a large family of growth factors, termed the neuregulins (NRGs), in this developmental progression has begun to be elucidated. NRGs are produced by several cell types, including developing sensory and motor neurons, whose axons will project to the peripheral nerves. In NRG knockout animals, there is a severe reduction in the number of Schwann cell precursors in neural crest-derived peripheral ganglia, which indicates that NRGs are important beginning early in Schwann cell development. Presented here is a brief update of recent progress in our understanding of the actions of NRGs in Schwann cell development, and of the interactions between NRGs and their receptors.