Role of Casein Kinase 2 (CK2) for the Progression of Cell Cycle and Growth Control

Abstract

Casein kinase 2(CK2) is a highly pleiotopic Ser/Thr protein kinase. Genetic, biochemical, and cell biological studies have indicated the involvement of this enzyme in the control of cell proliferation and in signal transduction. CK2 has long been considered a constitutively non-regulated kinase. However, we have shown that CK2 activation occurred during cell cycle progression in response to growth stimuli of G0-arrested human normal fibroblasts. As the downstream target for CK2, we find that eukaryotic translation initiation factor eIF5 is phosphorylated at Ser 389 and Ser390. Results obtained by the expression of eIF5 mutants that lack CK2 phosphorylation sites suggest that CK2 may be involved in the regulation of cell cycle progression through the phosphorylation of a key molecule for translation.