Cell invasion involves membrane-active and calmodulin-binding properties of the CyaA toxin translocation domain

The molecular mechanisms and forces involved in the translocation of bacterial toxins into host cells are still a matter of intense research. Bordetella pertussis, the causative agent of whooping cough, produces an adenylate cyclase (CyaA) toxin that plays an essential role in the early stages of respiratory tract colonization. CyaA displays a unique intoxication pathway of human cells via a direct translocation of its catalytic domain (AC) across the plasma membrane. Once in the cytosol, AC impairs the physiology of immune cells, leading to cell death.