In order to control cellular processes and thwart the immune system, the bacterium Legionella pneumophilia, the cause of the notorious Legionnaires’ disease, releases hundreds of enzymes. Biochemists at Goethe University have now elucidated important details in the interaction of bacterial effectors. They discovered how the regulatory enzyme SidJ keeps other dangerous virulence factors in check.
The incidence of Legionnaires’ disease has increased in the past two decades. The natural habitat of Legionella is freshwater biotopes, where they mainly reproduce in amoebae. In addition, Legionella can also colonize water tanks or pipes and spread, for example, via poorly maintained air-conditioning systems. Contaminated aerosols are released into the air and trigger the infection. The pathogens cause, among others, pneumonia, which is often fatal in elderly patients or individuals with a weak immune system.