P0, the major protein of PNS myelin, is considered to play a critical role in the compaction and stabilization of myelin lamellae. The protein undergoes extensive posttranslational modifications, including phosphorylation at multiple serine moieties in the cytoplasmic region. Recently, we demonstrated that P0 is phosphorylated on one or more tyrosine residues in rat nerve homogenates after incubation. In this study, we show that P0 phosphorylated on tyrosine is also present in the intact animal. The proportion of P0 molecules phosphorylated on tyrosine is highest during the first postnatal week, a period that coincides with the most rapid period of myelin deposition in the PNS. A peptide that constitutes the cytoplasmic domain was isolated from purified P0 and shown by immunochemical and chemical means to be phosphorylated on the tyrosine corresponding to Y191 in the intact protein. No evidence was obtained supporting the possibility that P0 is phosphorylated on other tyrosine residues. The sequence of amino acids surrounding Y191 resemble known substrate phosphorylation sites for some nonreceptor cytoplasmic tyrosine kinases, as well as tyrosine-based recognition signals associated with clathrin vesicle-mediated endocytosis.
|Number of pages||8|
|Journal||Journal of Neurochemistry|
|Publication status||Published - 2000|
- Sciatic nerve
- Tyrosine phosphorylation
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience