The Type VI secretion system (T6SS) is a bacterial nanomachine that fires toxic proteins into target cells. Deployment of the T6SS represents an efficient and widespread means by which bacteria attack competitors or interact with host organisms and may be triggered by contact from an attacking neighbor cell as a defensive strategy. In Cell Reports, Dr Sarah Coulthurst and her team observe a multi-stage, dynamic assembly process for the secretion system machinery in the pathogen Serratia marcescens. Serratia belongs to a class of bacteria called "opportunistic Enterobacteria", which frequently cause antibiotic-resistant hospital-acquired infections. Additionally, Dr Coulthurst found that Serratia, in contrast with Pseudomonas aeruginosa, uses its T6SS to act aggressively - choosing to fire without waiting for an attack from a potential victim. Such unprovoked attacks broaden its target range and may enhance its fitness in highly competitive niches. It is likely that the ability of T6SS to be flexibly deployed will play key roles in determining the composition of many polymicrobial populations, with associated implications for both health and disease.
This work was published in Cell Reports.
1. Visualization of the Serratia Type VI Secretion System Reveals Unprovoked Attacks and Dynamic Assembly
Gerc, Amy J., Diepold, Andreas, et al. Cell Reports , Volume 12 , Issue 12 , 2131 - 2142