This is the major myelin protein from the central nervous system. It plays an important role in the formation or maintenance of the multilamellar structure of myelin. Colocalizes with SIRT2 in internodal regions, at paranodal axoglial junction and Schmidt-Lanterman incisures of myelin sheat. Defects in Plp1 are the cause of the dysmyelinating diseases Jimpy and Rumpshaker (rsh). Belongs to the myelin proteolipid protein family.