Bacteria have different defense mechanisms to protect themselves from the bacteriophage (Virus) attack. Some of the most prominent defense systems are the Restriction modification system and the CRISPR Cas system.
Cohen et al. have discovered a new Bacterial defense mechanism in some Bacteria like Vibrio Cholerae. These Bacteria use a very conserved mechanism called cGAS-STING which is very prominent in the innate immunity of animals. This pathway operates through the synthesis of cyclic GMP-AMP (cGAMP).
When a virus infects Bacteria, cGAS proteins produce cGAMP which leads to activation of associated phospholipase. The activated Phospholipase then degrades the bacterial cell membrane leading to cell death. As this event occurs before the phage could replicate to high density, it prevents the other bacteria from getting infected.
1. Cyclic GMP-AMP signaling protects Bacteria against viral infection. Nature 574,