Type III secretion system (T3SS) effectors containing transmembrane domains are able to avoid insertion in bacterial membranes and being correctly targeted to the T3SS. Bacteria achieve this either by passive discrimination, where transmembrane effectors have a lower hydrophobicity than transmembrane proteins, or by active discrimination, where the presence of a T3SS chaperone is required. I am trying to understand the molecular processes at both gene and protein occurring in the bacteria that make possible an efficient T3S of these effectors into host cells.