Fig. 5.

VgrG3 delivery into target bacteria. Shown are all possible outcomes subsequent to V. cholerae T6SS attack. (A) If the VgrG/PAAR spike complex on the tip of the Hcp tube is delivered into periplasm, then VgrG3 can have an effect there. (B) If the spike complex penetrates all the way into the cytosol then the VgrG effector will initially have no function. (C) If the target cell then traffics the VgrG3 effector to the periplasm, then the effector will be able to attack its peptidoglycan substrate there. (D) Both cytosolic and periplasmic delivery of effectors can occur if bacterial target cells remain in close proximity long enough as might be the case in a stable structure such as a biofilm.