Cyclic di-GMP Acts as a Cyclin-like Molecule to Control Cell Cycle Progression in Bacteria

Cell division is a complicated process that requires not only cell growth and division but also faithful replication of the mother cell genome. These processes need to be timed appropriately to end up with two viable daughter cells. In eukaryotic cells cell cycle progression is controlled by oscillating proteins called cyclins that bind and activate cyclin-dependent kinases (Cdks).

Bacteria, like eukaryotic cells, have to tightly control cell division but how this is accomplished was poorly understood. Scientists at the Biozentrum of the University of Basel now show that oscillation of the small molecule second messenger cyclic di-GMP (c-di-GMP) drives the cell cycle in Caulobacter crescentus. c-di-GMP binds the essential cell kinase CckA, inhibits its kinase activity, stimulates its phosphatase activity, and thus initiates DNA replication and cell cycle progression. Furthermore, the uneven distribution of c-di-GMP across the mother cell helps establish two distinct daughter cells — a stalked cell that is replication competent but sessile and swarmer cell that is replication inert and motile. These findings suggest that c-di-GMP acts as a cyclin-like molecule to control cell cycle progression in bacteria.

Source: Biozentrum at the University of Basel