Proteolipid protein 1 is a protein associated with Pelizaeus-Merzbacher disease. It is a 4 transmembrane domain protein which binds strongly to other copies of itself on the extracellular side of the membrane. In a myelin sheath, as the layers of myelin wraps come together, PLP will bind itself and tightly hold the cellular membranes together.This gene encodes a transmembrane proteolipid protein that is the predominant myelin protein present in the central nervous system. The encoded protein functions in myelination. This protein may play a role in the compaction, stabilization, and maintenance of myelin sheaths, as well as in oligodendrocyte development and axonal survival. Mutations associated with this gene cause X-linked Pelizaeus-Merzbacher disease and spastic paraplegia type 2.