title: Host endoplasmic reticulum COPII proteins control cell-to-cell spread of the bacterial pathogen Listeria monocytogenes.
abstract: Listeria monocytogenes is a food-borne pathogen that uses actin-dependent motility to spread between human cells. Cell-to-cell spread involves the formation by motile bacteria of plasma membrane-derived structures termed 'protrusions'. In cultured enterocytes, the secreted Listeria protein InlC promotes protrusion formation by binding and inhibiting the human scaffolding protein Tuba. Here we demonstrate that protrusions are controlled by human COPII components that direct trafficking from the endoplasmic reticulum. Co-precipitation experiments indicated that the COPII proteins Sec31A and Sec13 interact directly with a Src homology 3 domain in Tuba. This interaction was antagonized by InlC. Depletion of Sec31A or Sec13 restored normal protrusion formation to a Listeria mutant lacking inlC, without affecting spread of wild-type bacteria. Genetic impairment of the COPII component Sar1 or treatment of cells with brefeldin A affected protrusions similarly to Sec31A or Sec13 depletion. These findings indicated that InlC relieves a host-mediated restriction of Listeria spread otherwise imposed by COPII. Inhibition of Sec31A, Sec13 or Sar1 or brefeldin A treatment also perturbed the structure of cell-cell junctions. Collectively, these findings demonstrate an important role for COPII in controlling Listeria spread. We propose that COPII may act by delivering host proteins that generate tension at cell junctions.
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors.forename: Antonella
authors.initials: A
authors.lastname: Gianfelice
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors.forename: Phuong H B
authors.initials: PH
authors.lastname: Le
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors.forename: Luciano A
authors.initials: LA
authors.lastname: Rigano
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors.forename: Susan
authors.initials: S
authors.lastname: Saila
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors.forename: Georgina C
authors.initials: GC
authors.lastname: Dowd
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
authors.forename: Tina
authors.initials: T
authors.lastname: McDivitt
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA.
authors.forename: Nilakshee
authors.initials: N
authors.lastname: Bhattacharya
authors.affiliation: Institute of Molecular and Cell Biology, Singapore.
authors.forename: Wanjin
authors.initials: W
authors.lastname: Hong
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Stagg
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors.forename: Keith
authors.initials: K
authors.lastname: Ireton
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D018938:Caco-2 Cells; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D020895:Enterocytes / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D008089:Listeria monocytogenes / Q000502:physiology*; D008124:Locomotion; D025941:Protein Interaction Mapping; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D033921:Vesicular Transport Proteins; C103178:inlC protein, Listeria monocytogenes