Phosphorylation of P0 Glycoprotein in Peripheral Nerve Myelin

Masaru Suzuki, Yasushi Sakamoto, Kunio Kitamura, Kohji Fukunaga, Hideyuki Yamamoto, Eishichi Miyamoto, Keiichi Uyemura

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

Abstract: The P0 protein in mammalian PNS myelin is known to undergo several posttranslational modifications, such as glycosylation, acylation, sulfation, and phosphorylation. Phosphorylation of purified P0 protein in vitro was studied comparatively using three enzymes, i.e., calcium/phospholipid‐dependent protein kinase (protein kinase C), calcium/calmodulin‐dependent protein kinase II (CaM kinase II), and the catalytic subunit of cyclic AMP‐dependent protein kinase (A kinase). The phosphorylation of P0 protein by CaM kinase II was the greatest, followed by that by protein kinase C; phosphorylation by A kinase, however, was much lower. In order to identify phosphorylation sites, P0 protein was phosphorylated with [32P]ATP and each kinase and then digested with lysylendopeptidase. The resulting phosphopeptides were isolated by HPLC. Subsequent amino acid sequence analysis and comparison with the known sequence of P0 protein revealed that Ser181 and Ser204 were strongly phosphorylated by both protein kinase C and CaM kinase II. In addition, Ser214 was also phosphorylated by protein kinase C, but not by CaM kinase II. Because all of these sites are located in the cytoplasmic domain of P0 protein, phosphorylation may be important for maintenance of the major dense line of PNS myelin.

Original languageEnglish
Pages (from-to)1966-1971
Number of pages6
JournalJournal of Neurochemistry
Volume55
Issue number6
DOIs
Publication statusPublished - 1990 Dec
Externally publishedYes

Keywords

  • Calmodulin‐dependent protein kinase
  • Glycoprotein
  • Myelin
  • P protein
  • Phosphorylation
  • Protein kinase C

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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