Peripheral myelin protein 22

Growth arrest-specific protein 3 (GAS-3), also called peripheral myelin protein 22 (PMP22), is a protein which in humans is encoded by the PMP22 gene.

PMP22 is a 22 kDa transmembrane glycoprotein made up of 160 amino acids, and is mainly expressed in the Schwann cells of the peripheral nervous system. Schwann cells show high expression of PMP22, where it can constitute 2-5% of total protein content in compact myelin. Compact myelin is the bulk of the peripheral neuron's myelin sheath, a protective fatty layer that provides electrical insulation for the neuronal axon. The level of PMP22 expression is relatively low in the central nervous system of adults.