Calcium ion stimulated endogenous protein kinase catalyzed phosphorylation of peripheral and central nerve myelin proteins: comparison between normal and genetically dystrophic mouse.

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 (Po) as well as other basic proteins (P1 and P2) were phosphorylated. Ca2+, 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 ofthe dystrophic mouse was observed. Interestingly, the dystrophic sciatic nerve myelin phosphorylation, compared to normal, was higher.