THE PKR PROTEIN-KINASE - AN INTERFERON-INDUCIBLE REGULATOR OF CELL-GROWTH AND DIFFERENTIATION

Post-translational modifications such as protein phosphorylation provi de an important mechanism by which the functional activity of proteins can be controlled and, hence, biological processes regulated. Interfe rons (IFN) are a multigene family of cytokines that can profoundly aff ect a wide variety of functions in animal cells including virus replic ation, cell growth and differentiation, and the immune response. Chang es in protein phosphorylation mediated by the IFN-inducible, RNA-depen dent protein kinase (PKR) are implicated in the control of cell prolif eration mediated by IFNs. Our knowledge of the structure, regulation a nd function of PKR will be summarized in this brief review, with focus on those aspects of protein phosphorylation and interferon action inv olving PKR that are central to the roles of the enzyme in the control of cell growth and proliferation. (C) 1997 Elsevier Science Ireland Lt d.