Mutual stimulation by phosphatidylinositol-4-phosphate and myelin basic protein of their phosphorylation by the kinases solubilized from rat brain myelin.

Myelin basic protein and phosphatidylinositol-4-phosphate are phosphorylated in vitro by ATP and solubilized rat brain myelin. When both substrates are present together, the rate of phosphorylation of each is increased about eight-fold. It appears likely that the phosphate turnover of myelin basic protein and of phosphatidylinositol-4-phosphate are coupled in vivo.