150: Phosphorylation of myelin basic protein by vaccinia virus cores

Abstract

In the postinfectious encephalomyelitis associated with vaccinia virus, both direct viral effects and immunological factors have been invoked as causes of this disorder. In the present study we explored the possibility that the protein kinase associated with vaccinia virus could directly modify host proteins. Purified basic myelin protein or human myelin membranes were incubated in the presence of [γ−32P−] ATP with vaccinia virus cores. The phosphorylated products were analysed on SDS polyacrylamide gels. Our experiments demonstrate that purified basic myelin protein is both a substrate and an activator for the viral protein kinase. Unlike most mammalian protein kinases, cyclic AMP does not stimulate the viral enzyme. Of the myelin polypeptides only the basic protein is phosphorylated. These results indicate that the virus core associated protein kinase phosphorylates myelin basic protein in vitro and suggest that vaccinia virus has the potential of directly modifying a cellular membrane.