Glycogen is a polysaccharide consisting of glucose that is used by animals and humans as an energy storage compound. Many bacteria also produce this biopolymer and use it either to store energy or to convert it into osmoprotective substances that, for example, protect soil-dwelling bacteria against weather fluctuations. The decision to initiate glycogen breakdown is a highly-regulated process controlled by signals from the cell's environment but is poorly understood in bacteria.
The link between c-di-GMP and glycogen metabolism
Early as 1955, Nobel Prize winners Edmond Fischer and Edwin Krebs showed that a nucleotide-based signaling molecule - cyclic adenosine monophosphate (cAMP) - activates the breakdown of glycogen in humans. The current study from the group of Natalia Tschowri describes the discovery that bacteria have evolved a similar strategy. Like humans, they use a nucleotide-based second messenger - cyclic di-guanosine monophosphate (c-di-GMP) - to activate glycogen breakdown. c-di-GMP binds to the glycogen-degrading enzyme GlgX and stimulates its enzymatic activity by stabilizing the dimeric conformation.
The authors have published the results of the present study in the scientific journal Nature Communications: Allosteric regulation of glycogen breakdown by the second messenger cyclic di-GMP (Schumacher, Wörmann et al., Nat Commun, 2022).
