Maintenance of the Salmonella-containing vacuole in the juxtanuclear area: a role for intermediate filaments.

Until recently, intermediate filaments (IF) were thought to be only involved in resistance to physical stress and mechanical integrity of cells and tissues. Recent data indicate that IF play a much more important role in cellular physiology including organelle structure and positioning within the cell. Here, we show that Salmonella enterica serovar Typhimurium (S. typhimurium) induces in epithelial cells and macrophages the formation of an aggresome-like structure with a dramatic remodelling of cytoplasmic IF (vimentin and cytokeratin) networks and the adaptor proteins 14-3-3 which are recruited around intracellular S. typhimurium microcolonies. These rearrangements are not necessary for bacterial replication. Depletion of vimentin and cytokeratin by siRNA indicates that IF remodelling is required to maintain Salmonella microcolonies in the juxtanuclear area.