VP16 needs either Met30 ubiquitin ligase (left) or fused ubiquitin (right) for activity.
Tansey/AAA
Ubiquitination of some transcriptional activators may be necessary both to make them functional activators and to signal their destruction, according to a recent study from William Tansey (Cold Spring Harbor Laboratory, Cold Spring Harbor, NY) and colleagues. Tansey suggests that ubiquitination is a temporary licence for transcription that preprograms destruction into the very activation process, thus keeping activators under tight control.
Tansey has been trying to unite the proteolysis and transcription fields ever since he noticed that the determinants of ubiquitination and transcription activation were often overlapping or even inseparable. Selling this idea took some time. “It's counterintuitive,” he says. “You have proteins that are destroyed not when they are no longer needed but when they are at their most active. People have some trouble with this idea.”
In the new...
