Protein kinase CK2: a catalyst for biology, medicine and structural biochemistry

Abstract

Protein kinase signaling in the cell is well recognized as a key mechanism through which a whole variety of cellular functions are mediated. Considering that the phosphoproteome constitutes a significant part of the expressed genome, it is not surprising that this mode of signaling is involved in virtually all aspects of normal and abnormal cell activities. In particular, dysregulation of these signals in the cell appears to play a key role in diverse types of disease processes, and to that end, protein kinases have emerged as attractive targets in the generation of therapeutic approaches. In this context, protein kinase CK2 (adopted acronym for the former inappropriate name casein kinase II) has continued to attract the increasing attention for its involvement in diverse cellular activities in both the normal and the disease states. CK2 is one among the most highly conserved molecules and is present in every cell at an apparently strictly regulated level depending on the cell type. A great deal of current information suggests that the moderate upregulation of the enzyme level provokes enhanced oncogenic potential in cells, whereas its downregulation promotes cell death. Increased levels of CK2 have been observed in various cancers that have been examined and appear to be related to prognosis; thus, it would seem that elevated CK2 plays a dual role in cancer cell phenotype—promotion of cell growth and proliferation as well as potent suppression of apoptosis. The demonstration of the druggability of CK2 has stimulated efforts directed towards generating strategies to target CK2 for cancer therapy. Likewise, new roles for CK2 in diverse biologic processes continue to be recognized. Indeed, based on the current observations in the literature, it is fair to state that CK2 has emerged as a ‘‘master regulator’’ of cell functions. These various developments are highlighted in the contributions to the present Focused Issue of Molecular and Cellular Biochemistry. The articles published in this Focused Issue are selected from the presentations at the Sixth International Conference on CK2. The Sixth International Conference on Protein kinase CK2 was held 7–10 September 2010, at Wahn Castle in the historic city of Cologne, Germany, as ‘‘A symposium of the International Union of Biochemistry and Molecular Biology’’ organized by the Institute of Biochemistry, Department of Chemistry of the University of Cologne. The theme of the Sixth International Conference on CK2 was ‘‘Protein kinase CK2—a catalyst for biology, medicine and structural biochemistry’’. The meeting was attended by investigators who discussed recent developments in the field of CK2, and had a truly international representation of scientists from 20 different countries and several continents. The meeting was opened with welcome addresses by Professor Dr. Christiane Bongartz (Dean of Faculty of Arts and Humanities of the University of Cologne), by Professor Dr. Gunter Schwarz (Director in Chief of the Institute of Biochemistry, Department of Chemistry, Faculty of Mathematics and Natural Sciences of the University of Cologne), and by Dr. Karsten Niefind (Institute of Biochemistry, local organizer of the CK2 conference). Prior to the start of the regular meeting program, the participants K. Ahmed (&) Minneapolis VA Health Care System and University of Minnesota, Minneapolis, USA e-mail: ahmedk@umn.edu