title: A Brucella abortus cstA mutant is defective for association with endoplasmic reticulum exit sites and displays altered trafficking in HeLa cells.
abstract: Members of the genus Brucella are facultative intracellular pathogenic bacteria able to control maturation of their vacuoles. In several cell types, Brucella is able to reach a proliferation compartment derived from the endoplasmic reticulum (ER). Since ER exit site (ERES) functions are required for Brucella proliferation, we performed a yeast two-hybrid screen between human ERES-associated proteins and the predicted brucella proteome. This screening led to the identification of CstA, a conserved protein that specifically interacts with Sec24A, a component of the ERES. We found that a tagged CstA is secreted in Brucella abortus culture medium. This secretion is independent of the type IV secretion system VirB and the flagellum, suggesting that CstA is secreted through another system. We also discovered that a B. abortus cstA mutant is impaired for its association with the Sec23 ERES marker. The B. abortus cstA mutant displayed peculiar trafficking, with reduced association with LAMP1 and Calnexin 12 h post-infection in HeLa cells. However, its intracellular proliferation kinetics was not affected. The data reported here suggest that CstA could be directly or indirectly involved in the control of B. abortus intracellular trafficking in HeLa cells.
authors: Research Unit in Microorganisms Biology (URBM), University of Namur (FUNDP), Namur, Belgium.
authors: Marie
authors: M
authors: de Barsy
authors: Research Unit in Microorganisms Biology (URBM), University of Namur (FUNDP), Namur, Belgium.
authors: Aurélie
authors: A
authors: Mirabella
authors: Research Unit in Microorganisms Biology (URBM), University of Namur (FUNDP), Namur, Belgium.
authors: Jean-Jacques
authors: JJ
authors: Letesson
authors: Research Unit in Microorganisms Biology (URBM), University of Namur (FUNDP), Namur, Belgium.
authors: Xavier
authors: X
authors: De Bolle
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002003:Brucella abortus / Q000378:metabolism / Q000472:pathogenicity*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D004847:Epithelial Cells / Q000382:microbiology*; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D009154:Mutation; D021381:Protein Transport; D020543:Proteome; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D020543:Proteome; C530638:SEC24A protein, human; D033921:Vesicular Transport Proteins