Live cell imaging reveals novel functions of Salmonella enterica SPI2-T3SS effector proteins in remodeling of the host cell endosomal system.

Intracellular Salmonella enterica induce a massive remodeling of the endosomal system in infected host cells. One dramatic consequence of this interference is the induction of various extensive tubular aggregations of membrane vesicles, and tubules positive for late endosomal/lysosomal markers are referred to as Salmonella-induced filaments or SIF. SIF are highly dynamic in nature with extension and collapse velocities of 0.

Reorganization of the endosomal system in Salmonella-infected cells: the ultrastructure of Salmonella-induced tubular compartments.

During the intracellular life of Salmonella enterica, a unique membrane-bound compartment termed Salmonella-containing vacuole, or SCV, is formed. By means of translocated effector proteins, intracellular Salmonella also induce the formation of extensive, highly dynamic membrane tubules termed Salmonella-induced filaments or SIF. Here we report the first detailed ultrastructural analyses of the SCV and SIF by electron microscopy (EM), EM tomography and live cell correlative light and electron microscopy (CLEM).

Dynamic modification of microtubule-dependent transport by effector proteins of intracellular Salmonella enterica.

Intracellular Salmonella enterica translocate effector proteins that modify microtubule-dependent transport processes of the host cell and modulate the biogenesis of the Salmonella-containing vacuole (SCV). One functional consequence is the induction of tubular aggregates of endosomal membranes, termed Salmonella-induced filaments or SIFs, and further tubular membrane compartments have recently been described. SIFs are unique, highly dynamic compartments that form by modification of vesicular transport on microtubules.

Dynamic remodeling of the endosomal system during formation of Salmonella-induced filaments by intracellular Salmonella enterica.

The infection by Salmonella enterica results in the massive remodeling of the endosomal system of eukaryotic host cells. One unique consequence is the formation of long tubular endosomal compartments, so-called Salmonella-induced filaments (SIF). Formation of SIF requires the function of type III secretion system and is a requirement of efficient intracellular proliferation of Salmonella.