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The S almonella SpiC protein targets the mammalian Hook3 protein function to alter cellular trafficking
Author(s) -
Shotland Yoram,
Krämer Helmut,
Groisman Eduardo A.
Publication year - 2003
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2003.03668.x
Subject(s) - biology , endosome , lysosome , microbiology and biotechnology , phagolysosome , secretion , golgi apparatus , fusion protein , lipid bilayer fusion , cytosol , phagosome , biochemistry , phagocytosis , gene , endoplasmic reticulum , recombinant dna , membrane , intracellular , enzyme
Summary The Salmonella SpiC protein is secreted into the cytosol of macrophages via a unique type III secretion system that functions intracellularly to translocate proteins across the phagosomal membrane. The SpiC protein is required for survival within macrophages and inhibition of phagosome‐lysosome fusion in vivo , and it is sufficient to inhibit endosome‐endosome fusion in vitro . Here, we establish that SpiC targets the function of Hook3, a mammalian protein implicated in cellular trafficking. Purified GST‐SpiC pulled down Hook3 from murine macrophages, and anti‐Hook3 antibodies precipitated SpiC from the cytosol of Salmonella ‐infected macrophages. Expression of the spiC gene disrupted Golgi morphology in Vero cells and altered the distribution of lysosomes in macrophages, mimicking the phenotype of cells expressing a hook3 dominant‐negative mutant. By inactivating Hook3 function, the SpiC protein may alter the lysosome network and prevent phagosome‐lysosome fusion.