The major ribonucleoprotein-associated protein kinase of vesicular stomatitis virus is a host cell protein.

Ribonucleoprotein particles (RNPs) of vesicular stomatitis virus (VSV) were fractionated by column chromatography through Fractogel TSK HW-55F and by centrifugation through KCl sucrose. Analyses of fractions for protein content and for protein kinase activity indicated that the major peak of kinase activity did not correspond exactly with any of the VSV-specific proteins. Neither anti-NS nor anti-M IgG preparations inhibited protein kinase activity, and IgG did not act as an exogenous phosphate acceptor. Reconstitution of an RNP-enzyme complex did not result in a restoration of protein kinase activity. In vitro translation of VSV-specific poly(A)-containing RNA did not result in any detectable production of kinase activity. Thus, the major RNP-associated kinase is a host cell protein which is tightly bound to the RNP particle.