<p>The myelin sheath is a multi-layered membrane, unique to the nervous system, that functions as an insulator to greatly increase the velocity of axonal impulse conduction. The P0 glycoprotein, absent in the central nervous system [<cite idref="PUB00002447"/>], is a major component of the myelin sheath in peripheral nerves. It comprises a large extracellular N-terminal domain, a single transmembrane (TM) region, and a smaller positivelycharged intracellular domain. It is postulated that P0 is a structural element in the formation and stabilisation of peripheral nerve myelin [<cite idref="PUB00000799"/>], holding its characteristic coil structure together by the interaction of its positively-charged domain with acidic lipids in the cytoplasmic face of the opposed bilayer, and by interaction between hydrophobic globular `heads' of adjacent extracellular domains [<cite idref="PUB00002447"/>].</p> Myelin P0 protein