A novel stabilization mechanism for the type VI secretion system sheath
Patricia Bernal, R. Christopher D. Furniss, Selina Fecht, R Leung, Livia Spiga, Despoina A. I. Mavridou, Alain Filloux
Abstract
-containing T6SSs remains unknown. Here we discover a class of structural components that interact with short TssA proteins and contribute to T6SS assembly by stabilizing the polymerizing sheath from the baseplate. We demonstrate that the presence of these components is important for full sheath extension and optimal firing. Moreover, we show that the pairing of each form of TssA with a different class of sheath stabilization proteins results in T6SS apparatuses that either reside in the cell for some time or fire immediately after sheath extension. We propose that this diversity in firing dynamics could contribute to the specialization of the T6SS to suit bacterial lifestyles in diverse environmental niches.