Calcium Ion Stimulated Endogenous Protein Kinase Catalyzed Phosphorylation of Peripheral and Central Nerve Myelin Proteins: Comparison between Normal and Genetically Dystrophic Mouse

Abstract

Myelin isolated from the peripheral (PNS) and central nervous system (CNS) of mouse contained a protein kinase which catalyzed phosphorylation of myelin proteins. In the case of CNS myelin, small and large basic proteins were phosphorylated whereas in the case of PNS myelin, a glycoprotein (P(0)) as well as other basic proteins (P(1) and P(2)) were phosphorylated. Ca^2+, but not adenosine 3',5'-monophosphate (cyclic AMP), markedly (5- to 10-fold) stimulated phosphorylation of PNS and CNS myelin proteins. There was no difference between the normal and dystrophic mouse CNS myelin phosphorylation. However, a marked decrease in the cauda equina PNS myelin phosphorylation of the dystrophic mouse was observed. Interestingly, the dystrophic sciatic nerve myelin phosphorylation, compared to normal, was higher.