SCAMP3 is a component of the Salmonella-induced tubular network and reveals an interaction between bacterial effectors and post-Golgi trafficking.
Salmonella enterica are facultative intracellular bacterial pathogens that proliferate within host cells in a membrane-bounded compartment, the Salmonella-containing vacuole (SCV). Intracellular replication of Salmonella is mediated by bacterial effectors translocated on to the cytoplasmic face of the SCV membrane by a type III secretion system. Some of these effectors manipulate the host endocytic pathway, resulting in the formation in epithelial cells of tubules enriched in late endosomal markers, known as Salmonella-induced filaments (SIFs). However, much less is known about possible interference of Salmonella with the secretory pathway. Here, a small-interference RNA screen revealed that secretory carrier membrane proteins (SCAMPs) 2 and 3 contribute to the maintenance of SCVs in the Golgi region of HeLa cells. This is likely to reflect a function of SCAMPs in vacuolar membrane dynamics. Moreover, SCAMP3, which accumulates on the trans-Golgi network in uninfected cells, marked tubules induced by Salmonella effectors that overlapped with SIFs but which also comprised distinct tubules lacking late endosomal proteins. We propose that SCAMP3 tubules reflect a manipulation of specific post-Golgi trafficking that might allow Salmonella to acquire nutrients and membrane, or to control host immune responses.
Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK.
Luís Jaime
LJ
Mota
Amy E
AE
Ramsden
Mei
M
Liu
J David
JD
Castle
David W
DW
Holden
D001426:Bacterial Proteins / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism*; D034741:RNA, Small Interfering; D012480:Salmonella Infections / Q000378:metabolism* / Q000821:virology; D019779:Salmonella enterica / Q000166:cytology / Q000472:pathogenicity / Q000502:physiology*; D055571:Secretory Pathway; D014774:Virulence; D021601:trans-Golgi Network / Q000378:metabolism*
D001426:Bacterial Proteins; D015415:Biomarkers; D002352:Carrier Proteins; D008565:Membrane Proteins; D034741:RNA, Small Interfering; C466776:SCAMP2 protein, human; C109303:SCAMP3 protein, human; C440638:SPI-2 protein, Salmonella