CaMKII structure--an elegant design

Crystal structures of protein kinases continue to reveal new mechanisms for the regulation of catalytic activity of these enzymes. In this issue of Cell, Rosenberg et al. (2005) report the structure of the catalytic and regulatory domains of CaMKII, a protein kinase important in the cellular response to changes in intracellular calcium ion concentration. This study provides new mechanistic insights into the workings of this finely tuned molecular machine.