Myelin protein zero

Myelin protein zero (P0, MPZ) is a is_associated_with::glycoprotein which in humans is encoded by the MPZ gene. P0 is a major structural component of the is_associated_with::myelin sheath, and its deficiency due to various is_associated_with::mutations in the MPZ gene is associated with is_associated_with::Charcot–Marie–Tooth disease and is_associated_with::Dejerine–Sottas disease.

Function
The is_associated_with::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, is a major component of the is_associated_with::myelin sheath in peripheral is_associated_with::nerves. It comprises a large is_associated_with::extracellular N-terminal domain, a single transmembrane (TM) region, and a smaller positively charged is_associated_with::intracellular domain. It is postulated that P0 is a structural element in the formation and stabilisation of peripheral nerve myelin, holding its characteristic coil structure together by the interaction of its positively charged domain with is_associated_with::acidic is_associated_with::lipids in the is_associated_with::cytoplasmic face of the opposed bilayer, and by interaction between is_associated_with::hydrophobic globular `heads' of adjacent extracellular domains.

Interactions
Myelin protein zero has been shown to interact with is_associated_with::peripheral myelin protein 22.