The myelin-associated glycoprotein is phosphorylated in the peripheral nervous system.
Phosphorylation of the myelin-associated glycoprotein (MAG) in the peripheral nervous system is demonstrated by immunoprecipitation from myelin proteins radiolabeled in vivo, in nerve slices and in a cell-free system. Phosphoamino acid analysis of immunoprecipitated MAG revealed the presence of radioactivity in phosphoserine, but not in phosphothreonine or phosphotyrosine. Only the shorter isoform of MAG (S-MAG) was detected by immunostaining of nitrocellulose sheets with anti-MAG anti-serum after enzymatic deglycosylation of immunoprecipitated MAG labeled in nerve slices. Autoradiography of the same Western blots revealed that most of the radioactive phosphate was in S-MAG, demonstrating that the polypeptide backbone of S-MAG is phosphorylated in the PNS.
Department of Pediatrics, Washington University School of Medicine, St. Louis, MO.
H C
HC
Agrawal
A B
AB
Noronha
D
D
Agrawal
R H
RH
Quarles
D000818:Animals; D002474:Cell-Free System; D002490:Central Nervous System / Q000378:metabolism; D066298:In Vitro Techniques; D009185:Myelin Proteins / Q000378:metabolism*; D018992:Myelin-Associated Glycoprotein; D009836:Oligodendroglia / Q000378:metabolism; D010525:Peripheral Nerves / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D051381:Rats; D011919:Rats, Inbred Strains; D012583:Schwann Cells / Q000378:metabolism
D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein; D010750:Phosphoproteins