Protein Composition of Myelin of the Peripheral Nervous System

Abstract

Abstract— Myelin was purified from the peripheral nervous system (PNS) of several species. The protein composition of these preparations was examined by discontinuous polyacrylamide gel electrophoresis in buffers containing sodium lauryl sulphate. Proteins characteristic of all samples include, in order of increasing mobility: a series of high molecular weight proteins, the major peripheral nerve protein (P0), two uncharacterized proteins, and two basic proteins (P1 and P2). Quantitative results, obtained by densitometry of gels stained with Fast Green showed differences in protein distribution, both between species, and from different types of nerves obtained from the same animal. The relative amounts of P1 and P2 proteins were the most variable; e.g. myelin from guinea‐pig sciatic nerve had little or no P2 protein, whereas 15 per cent of the myelin protein of beef posterior intradural root was Pz protein. P0, P1 and P2 proteins from rabbit sciatic nerve and P0 and P2 proteins from beef dorsal and ventral intradural roots were purified and their amino acid compositions were determined. Our results indicated that the P1 protein is very similar in size and amino acid composition to the basic protein of central nervous system myelin, whereas the P0 and P2 proteins are unique to the PNS.

Myelin protein zero mutations and the unfolded protein response in Charcot Marie Tooth disease type 1B

“…Myelinating Schwann cells increase their plasma membranes several thousand fold to generate a myelin sheath which requires a marked upregulation of protein and lipid levels 14. MPZ itself comprises up to 50% of all myelin proteins15 and approximately 2% of all Schwann Cell transcripts during the peak of myelination 16. Normally, newly synthesized MPZ is folded and post‐translationally modified into its native conformation by ER‐protein quality control pathways (ERQC) that consist of various chaperones and other molecules 17, 18.…”

Interactions of Sox10 and Egr2 in myelin gene regulation

“…Myelin Protein Zero (Mpz) is the most abundant protein component of peripheral myelin (Greenfield et al, 1973) and is necessary for the formation of compact myelin (Giese et al, 1992). Since the identification of the gene encoding Mpz (Lemke and Axel, 1985), several studies have probed its transcriptional regulation.…”

P‐0 Glycoprotein Overexpression Causes Congenital Hypomyelination Of Peripheral Nerves

“…P 0 mRNA ( ‫ف‬ 8% of total mRNA) and protein ( Ͼ 50% of peripheral myelin protein; Greenfield et al, 1973) are by far the most abundant in nerve. P 0 is a single-pass transmembrane protein with an extracellular immunoglobulin-like domain, and a cytoplasmic tail enriched in basic residues (Lemke and Axel, 1985;Shapiro et al, 1996).…”