Abstract
Covalent addition of a phosphate to enzymes and other cellular proteins often turns its activity on or off, or otherwise regulates its function. Now in his research commentary, Hafen summarizes two reports in this week9s issue (Westphal and Camps) that show the intimate association and mutual regulation of the two key enzymes for controlling phosphate addition in cells--kinases and phosphatases. Hafen postulates that this interdependence will prove to be a universal property of pairs of kinases and phosphatases.