Abstract
Salmonella is an intracellular bacterial pathogen that replicates within a membrane-bound vacuole in host cells. The major lysosomal membrane proteins 1 and 2 (LAMP-1 and LAMP-2) are recruited to the Salmonella-containing vacuole as well as Salmonella- associated filaments (Sifs) that emerge from the vacuole. LAMP-1 is a dominant membrane marker for the vacuole and Sifs. Its colocalization with both is dependent on a major secreted bacterial virulence protein, SifA. Here, we show that SifA is required for the recruitment of LAMP-2 and can be used as a second independent marker for both the bacterial vacuolar membrane and Sifs. Further, RNAi studies revealed that in LAMP-1 depleted cells, the bacteria remain membrane bound as measured by their association with LAMP-2 protein. In contrast, LAMP-2 depletion increased the amount of LAMP-1 free bacteria. Together, the data suggests that despite its abundance, LAMP-1 is not essential, but LAMP-2 may be partially important for the Salmonella-containing vacuolar membrane.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Bacterial Proteins / genetics
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Biological Transport / genetics
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Cell Proliferation / drug effects
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Gene Knockdown Techniques
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Glycoproteins / genetics
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HeLa Cells
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Humans
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Intracellular Membranes / metabolism
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Lysosomal Membrane Proteins / genetics*
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Lysosomal Membrane Proteins / metabolism
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Lysosomal Membrane Proteins / physiology
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Lysosomal-Associated Membrane Protein 2
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Protein Transport / drug effects
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Protein Transport / physiology
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RNA, Small Interfering / pharmacology
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Salmonella Infections / genetics*
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Salmonella Infections / metabolism*
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Salmonella Infections / pathology
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Salmonella typhimurium / genetics
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Salmonella typhimurium / metabolism*
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Vacuoles / genetics
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Vacuoles / metabolism
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Vacuoles / microbiology*
Substances
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Bacterial Proteins
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Glycoproteins
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LAMP1 protein, human
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LAMP2 protein, human
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Lysosomal-Associated Membrane Protein 2
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Lysosomal Membrane Proteins
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RNA, Small Interfering
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SifA protein, Salmonella