Abstract
Endogenous protein phosphorylation was studied in extracts of hamster fibroblasts infected with pseudorabies virus. The major phosphorylation was detected quite late in infection and involved an acidic protein of Mr 62,000. It was catalysed by an enzyme activity with the properties of cellular casein kinase II. Two-dimensional gel analysis was used to demonstrate that this same protein was also phosphorylated in vivo. The phosphoprotein was detected in mature virions and is most likely viral in origin.