When bacteria such as Salmonella or Yersinia cause fever, diarrhea or abdominal pain, tiny “injection needles” are at work: their type 3 secretion system, or T3SS for short, shoots bacterial virulence proteins directly into the eukaryotic host cells. Researchers have thought of using bacterial injection devices to introduce proteins into eukaryotic cells. A Max Planck research team has now succeeded in controlling the injection system optogenetically, i.e. with light. In the future this will enable to use the system in biotechnological or medical applications. Learn More