Cell cycle control in archaea

To propagate, cells must first duplicate all of their constituent parts and then partition everything precisely at division to give rise to two new viable daughter cells. In complex cells like ours, these events in the "cell division cycle" are ordered by the rise and fall of CDK-Cyclins - a kind of molecular clock. Intriguingly, Sulfolobus cells (with which we share a common ancestor >1 billion years ago) possess an ordered cycle similar to ours whilst lacking a CDK-Cyclin clock. How then do these archaea regulate their cell cycle? Remarkably, we recently discovered that these archaea use selective protein degradation to reset their cell cycle at division - just as our cells do. Our goal now is to determine the role and regulation of this wave of protein degradation. We expect this work to reveal common principles of cell cycle regulation and the origins of eukaryotic cell cycle control.