sentences:  It is a 4 transmembrane domain protein which is proposed to bind 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 (CNS).