title: Global impact of Salmonella type III secretion effector SteA on host cells.
abstract: Salmonella enterica is a Gram-negative bacterium that causes gastroenteritis, bacteremia and typhoid fever in several animal species including humans. Its virulence is greatly dependent on two type III secretion systems, encoded in pathogenicity islands 1 and 2. These systems translocate proteins called effectors into eukaryotic host cell. Effectors interfere with host signal transduction pathways to allow the internalization of pathogens and their survival and proliferation inside vacuoles. SteA is one of the few Salmonella effectors that are substrates of both type III secretion systems. Here, we used gene arrays and bioinformatics analysis to study the genetic response of human epithelial cells to SteA. We found that constitutive synthesis of SteA in HeLa cells leads to induction of genes related to extracellular matrix organization and regulation of cell proliferation and serine/threonine kinase signaling pathways. SteA also causes repression of genes related to immune processes and regulation of purine nucleotide synthesis and pathway-restricted SMAD protein phosphorylation. In addition, a cell biology approach revealed that epithelial cells expressing steA show altered cell morphology, and decreased cytotoxicity, cell-cell adhesion and migration.
authors.affiliation: Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain. Electronic address: e_cardenal@us.es.
authors.forename: Elena
authors.initials: E
authors.lastname: Cardenal-Muñoz
authors.affiliation: Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain. Electronic address: ggpozo@us.es.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Gutiérrez
authors.affiliation: Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain. Electronic address: framos@us.es.
authors.forename: Francisco
authors.initials: F
authors.lastname: Ramos-Morales
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D002448:Cell Adhesion / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000382:microbiology*; D005109:Extracellular Matrix / Q000378:metabolism; D044404:Genomic Islands; D006367:HeLa Cells; D006801:Humans; D012486:Salmonella typhimurium / Q000472:pathogenicity*; D059467:Transcriptome; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; C000590973:SteA protein, Salmonella typhimurium; D037521:Virulence Factors
keywords: Cell–cell adhesion; Human epithelial cell; Microarray; Salmonella enterica; SteA; Type III secretion system