The β-encapsulation cage of rearrangement hotspot (Rhs) effectors is required for type VI secretion
Sonya Donato, Christina M. Beck, Fernando Garza‐Sánchez, Steven J. Jensen, Zachary C. Ruhe, David A. Cunningham, Ian M. Singleton, David A. Low, Christopher S. Hayes
Abstract
Significance Many bacteria use the type VI secretion system (T6SS) to compete with other microorganisms in the environment. These systems eject spear-like projectiles that impale neighboring cells to deliver lethal toxins. Here, we report that antibacterial toxins encoded by rearrangement hotspot ( rhs ) genes are critical for assembly of the T6SS apparatus in Enterobacter cloacae . Rhs proteins fortify the trimeric cell-penetrating spike at the tip of the projectile, and their toxin-encapsulating cage structures are required for full secretion activity. These findings suggest that Rhs proteins mediate a quality control checkpoint to ensure that the spike is loaded with toxic cargo before the cell assembles the T6SS apparatus.